JP3258175B2 - Method for producing non-doped or doped silica glass body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing hollow tubes, porous tubes, rods and other substantially bubble-free silica glass bodies having a circular or polygonal cross section perpendicular to the axial direction, and more particularly to a crystal. The present invention relates to a method for producing a non-doped silica glass body or a doped silica glass body using porous silica powder or amorphous silica powder as a main raw material. However, a non-doped silica glass body refers to a high-purity silica glass body, and a doped silica glass body refers to a silica glass in which metal ions are dissolved in a silica glass matrix, a silica glass in which metal particles are dispersed, and a ceramic particle in which ceramic particles are dispersed. Shall be shown.

[0002]

2. Description of the Related Art Conventionally, a jig made of silica glass having high chemical stability and heat resistance has been used as a semiconductor jig incorporated in a wafer heat treatment apparatus, and this kind of jig is orthogonal to an axial direction. The cross section is formed using a circular or angular silica glass rod. Since all of these jigs are consumables, all of the jig material rods are required to have a high-purity, high dimensional accuracy, a low-cost manufacturing method with no quality variation.

At the time of drawing an optical fiber, a dummy rod is attached to the tip of a preform rod, which is the base material of the fiber, and processing is performed so that the dummy rod is drawn until drawing conditions are stabilized. Such a rod needs to have as few bubbles as possible and low cost so as not to be cut off during drawing.

On the other hand, in recent years, in a sensor for detecting a temperature, a gas amount, and the like in a high-temperature atmosphere, in order to improve insulation and heat resistance, the above-mentioned porous silica glass tube having a large number of axial holes in the axial direction is provided. A sensor device in which a sensor is inserted has been developed. In such a multi-hole silica glass rod for a sensor, a rod having high purity and high dimensional accuracy without impurities is required.

[0005] In addition to the above, there are various processed products such as a quartz glass burner nozzle for the use of the perforated tube, but all of them require a tube and a rod with high purity and high dimensional accuracy. And the silica glass rod used for these processed silica glass products is to reduce bubbles as much as possible, maintain high dimensional accuracy, there is no scratch on the surface, other quality conditions such as high purity, low cost, square shape, It is necessary to easily manufacture any profile rod such as a hollow tube and a multi-hole tube.

A sputtering target material made of metal-doped silica glass doped with Ti, Ge, B, and P, and a phosphor and a laser oscillator made of metal-doped silica glass doped with a rare earth element have also been developed. These require uniform doping of a metal element and the like.

[0007] As a method for producing these non-doped silica glass rods or doped silica glass rods, a method in which quartz powder or quartz powder is filled into a sheathed tube in which one end of a quartz glass tube is sealed and heated and melted (hereinafter referred to as "the melting process"). The method is referred to as a powder-in-tube method). As disclosed in Japanese Patent Publication No. 43-7626 as a prior art of the powder-in-tube method, a number of sheathed tubes filled with quartz powder or quartz powder are inserted into a graphite melting crucible, There is a technique in which a material is inserted into a vacuum furnace, heated and melted at 1920 ° C. in a vacuum atmosphere, and the melt is drawn or drawn.

However, in such a conventional technique, a crucible is basically required, and there is impurity contamination from the crucible at the time of melting. Also, since the entire crucible is heated even under vacuum, even if the vacuum atmosphere is maintained, the entire filling area of quartz powder or quartz powder is evacuated by the weight of the raw material filled in the sheath tube. Therefore, it is unavoidable that a deposition gas or a residual gas from the powder is entrained during melting. In addition, in a manufacturing method in which the quartz powder is completely melted together with the sheath tube in the crucible, and a rod is drawn in a molten state, not only it becomes difficult to obtain a rod with high dimensional accuracy even if a die is used, The formation of rods and multi-hole rods is not possible.

In Japanese Patent Application Laid-Open No. 58-204830,
After filling the sheath-shaped silica glass container with quartz powder of a predetermined particle size, the inside of the container is set to a non-oxidizing atmosphere, and the container is partially heated by a heating means while rotating horizontally, and the heating means is moved to move the quartz powder. A method of melt vitrification as a whole is disclosed. However, in such a technique, since the heating means is moved, a long-sized product or an elongated product cannot be produced. Further, in this conventional technique, a mechanism for rotating a container filled with quartz powder is required, and the entire apparatus becomes large. Further, since the heating means is oxyhydrogen flame burner heating, dimensional control is difficult, and glass with high dimensional accuracy cannot be produced. Further, the present technology is suitable for manufacturing only one tube or rod having a predetermined size. With the configuration in which the container is supported at both ends as described above, it is not possible to produce a large number of small diameter rods and tubes.

A technique similar to the present invention is disclosed in
No. 282134, powdered synthetic quartz glass powder was filled in a silica glass tube having a double tube structure, introduced into a heating furnace using electricity or a flame as a heat source, heated and melted, and then stretched and integrated. A technique has been proposed in which a synthetic quartz glass layer having fine bubbles is formed between quartz glass layers having no bubbles. However, the prior art described above is to provide a foam layer in the middle of a silica glass tube, while the object of the present invention is to produce a silica glass rod and a tube which is substantially transparent and substantially bubble-free as a whole. Technical ideas are completely different.

[Problems to be solved by the invention]

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and is directed to a method for producing a high-purity silica glass rod having few bubbles. Another object of the present invention is to provide a method for producing a transparent silica glass rod having no scratches on the surface while maintaining high dimensional accuracy. It is another object of the present invention to provide a method for producing a transparent silica glass rod in which any profile rod such as a square, hollow or multi-hole tube can be easily produced at low cost without increasing the size of the measure. Another object of the present invention is to provide a method for producing a transparent silica glass rod capable of producing a uniformly mixed dope rod even when producing a silica glass containing a metal element or a metal element compound.

[0012]

SUMMARY OF THE INVENTION The present invention provides a method for producing a silica glass body or a non-doped silica glass body doped with a metal element or a metal element compound as described above, particularly a substantially bubble-free silica glass body. The characteristic feature is that one or a plurality of small-diameter inner pipes are inserted into a hollow silica glass hollow body having a single-pipe structure in which one end is sealed, or a large-diameter outer pipe, and one end of these pipes is closed. A fused silica glass hollow body was formed by fusion sealing, and then the amorphous silica powder was filled into at least the tip of the sealed end side of the silica glass hollow body, and further filled with the main raw material silica powder. A first point is that a heated body is prepared, and the inside of the heated body is heated and melted gradually by zone melting upward from the lower end while the inside of the heated body is set to a reduced pressure atmosphere.

In this case, it is generally preferable to move the silica powder-filled heated body vertically downward in terms of miniaturization of the apparatus. However, the heating means is moved in the axial direction of the heated body and the heated body is moved in the axial direction. It may be moved upward from the lower end side. The reduced pressure atmosphere is preferably a vacuum of 1 KPa or less. Further, substantially bubble-free means that the total cross-sectional area of bubbles existing in 100 cm ³ of the glass body is 1 mm ² or less. However,
The measuring method follows DIN 58927 (1970).

[0014]

According to this invention, the whole body to be heated filled with silica powder is not heated at the same time. Since the heating is performed gradually in a zone, the deposition gas and the residual gas from the powder can be heated and melted substantially without bubbles without being entrained. It is preferable to use a cylindrical electric furnace or another electric melting furnace as the zone melting means, but the invention is not limited to this.

Incidentally, a technique similar to the present invention is disclosed in
In Japanese Patent No. 3-282134, there is a technique of introducing into a circular heating furnace, heating and melting, and then stretching and integrating to form a quartz glass tube. However, such a technique involves forming fine bubbles in the middle of the thick part of the tube. To form a synthetic quartz glass layer. On the other hand, an object of the present invention is to produce a silica glass rod and a tube which is substantially transparent and is substantially bubble-free, and the premise and technical idea thereof are completely different. Although it is used, such amorphous silica powder has no so-called melting point and gradually softens from about 1600 ° C. It becomes glass with many. Therefore, the object of the prior art is achieved.

Therefore, a feature of the present invention is that crystalline silica powder is basically used as a main raw material. That is, since crystalline silica powder such as quartz powder has a melting point at 1730 ° C., it is melted at a stretch by heating it to 1730 ° C. or more, and generation of bubbles in the molten glass can be suppressed as much as possible. However, crystalline silica powder such as quartz powder is 573
℃ has a transition point from α-type to β-type, before the viscosity of the hollow silica glass body decreases at the start of heating, the rapid change due to the transition from α-type to β-type of the quartz powder inside the hollow tube. The expansion causes the hollow body to break.

Therefore, the present invention provides a method of filling the hollow body with a powder containing amorphous silica powder as a main component at the tip of the filling area.
Thereafter, the main raw material silica powder mainly composed of quartz powder or other crystalline silica powder is filled. As a result, the transition from α-type to β-type is present at the lower end of the filling zone to be firstly zone-heated in order to cause a powdery material mainly composed of the amorphous silica powder having no transition point to exist. Pipes can be prevented from breaking.

In the upper region, the viscosity of the hollow body has already been reduced by the preheating of the heat zone, and even if the crystalline silica powder in that portion undergoes a rapid expansion due to the transition from α-type to β-type, the tube is destroyed. Can be effectively blocked. The filling width of the amorphous silica powder is determined by the heat zone (soaking width) of the zone heating means.
It is necessary to be larger, but if it is too large, the existence area of the substantially bubble-free silica glass is reduced and the productivity is reduced. Therefore, it is preferably less than 20% of the total filling amount of the powder. .

The crystalline silica powder is at least one kind of crystalline silica of natural quartz powder, synthetic quartz powder, and synthetic cristobalite powder, and has a particle size of 10 to 1000 μm.
It is preferable that the content ratio of the fine particles within the range of 50 to 200 and less than 10 μm is 0.1 wt% or less. However, if the particle size is less than 10 μm, pressure loss is likely to occur even if the chamber is evacuated, and the inside of the filling region cannot be evacuated. Contains a large amount of air bubbles, and uniform heat transfer becomes difficult due to the heat insulating effect. On the other hand, if the particle size is 1000 μm or more, uniformity cannot be obtained at the time of melting, and even if quartz powder is used, generation of air bubbles cannot be suppressed because of a large void between the powders.

For filling amorphous silica powder, the lower end of the hollow body is first filled with amorphous silica powder and then with a mixed powder of amorphous silica powder and crystalline silica powder (or the main raw material silica powder). Then, it is preferable that the main raw material silica powder is finally filled. Also, since the present invention can directly melt a single heated zone, it can be manufactured using a large-diameter hollow body having an outer diameter of 60 to 200 mm and a raw material powder filling length of 1 to 10 m. It is easy to manufacture a dummy rod for manufacturing an optical fiber.

When manufacturing a high-purity rod, there are cases where crystal powder cannot be used as described above. In such a case, it suffices that a substantially bubble-free silica glass rod can be produced even by using a high-purity amorphous silica powder such as synthetic silica glass. In such a case, the main raw material silica powder may be filled after performing a heat treatment in a hydrogen-containing atmosphere or a helium-containing atmosphere in advance. As a result, even if residual gases consisting of hydrogen and helium are present during the zone melting, they are occluded / dissolved in the molten glass at the time of melting, and generation of bubbles can be prevented. And it may be used silica powder obtained by mixing a metal element or a metal element compound in the main raw material silica powder in order to suppress the characteristics of the sheet Rikagarasu body, or may be a high-purity silica powder.

Next, the present invention provides a method of controlling the feeding speed (in the direction of gravity) of the object to be heated into the zone heating means and the pulling rate of the silica glass melted by the zone heating means (specific doping element). Is characterized in that a doped or undoped silica glass body is formed as a substantially bubble-free silica glass body. That is, in the present invention, since dimensional control is performed by controlling only the feed rate and the pulling rate, non-contact and pulling in the gravitational direction are performed. In addition, a silica glass rod having no scratches on the surface can be obtained.

In particular, in the present invention, the feed rate and the pull rate are controlled so that the ratio of the diameter of the object to be heated to the diameter of the transparent silica glass body is 以下 or less, so As well as achieving high precision, it is possible to prevent the occurrence of scratches on the surface. In this case, it is preferable that the thickness of the filling area of the object to be heated is set to 0.5 mm to (outer diameter) × 10% or less. If the thickness is less than 0.5 mm, the strength is insufficient. On the other hand, if it is (outer diameter) × 10% or more, the cost of the hollow body becomes large, and it has no industrial significance.

The above-mentioned invention can be applied to either a non-doped or doped silica glass body. And in the case of the doped silica glass member as described above, Shirikaga
Amorphous silica at least at the tip of the sealing end of the glass hollow body
This method is characterized in that a heated body is used which is filled with a main material silica powder mixed with a metal powder, an oxide thereof, a ceramic powder and the like in a silica filled area of a hollow body in an upper portion of the powder. By producing a doped silica glass body by zone melting of such a heated silica body, a doped silica glass body having substantially no bubbles and high dimensional accuracy can be obtained.

In particular, in a method for producing a sputtering target material and a non-linear optical material containing silica glass as a main component , at least a sealing end side of a hollow silica glass body is provided.
Amorphous silica powder is filled at the tip, and atomic numbers 5, 6, 13 to 15, and 22 to 3
A heated body filled with silica powder as a main raw material mixed with at least one or more doping powders of oxides, chlorides, iodides, nitrates, and carbonates of each of the elements 2 is melted in the same manner as described above. Thus, a non-linear optical material such as a sputtering target material or a meta-hala lamp can be manufactured.

In a method for manufacturing a fluorescent luminous body, a laser oscillating body, and a nonlinear optical body containing silica glass as a main component,
Amorphous at least at the tip of the sealed end side of the silica glass hollow body
Porous silica powder, and at least one of oxides, chlorides, iodides, nitrates, and carbonates of the elements having atomic numbers 57 to 71 is filled in the upper portion of the silica glass hollow body filling area.
A fluorescent material, a laser oscillator, or a non-linear optical material can be manufactured by subjecting a heated object filled with a main raw material silica powder mixed with more than one type of doping compound to the same zone melting as described above. In any of the above cases, the concentration of the specific doping element in the manufactured silica glass rod is 0.1 to 5 wt.
%, The mixing ratio of the powder for doping and the silica powder of the main raw material is preferably set.

[0027]

According to the invention, therefore, the following problems can be solved in producing a rod of a non-doped or doped silica glass body from various silica raw material powders.
A silica glass body that is practically bubble-free, has good dimensional accuracy, and has no scratches on its surface can be obtained. For example, when the diameter is 1 to 100 mm and the length is 1 m, the circumferential runout tolerance in the radial direction is (diameter) × 0.5% or less, the total runout tolerance in the radial direction is (diameter) × 1% or less. A transparent silica glass body having a total cross-sectional area of bubbles existing in 100 cm ³ of silica glass of 1 mm ² or less can be obtained. By controlling the feed speed and the pulling speed, not only can a tapered rod having a continuously different diameter be manufactured, for example, but also a rod can be manufactured from a small amount of raw material powder or a large amount of raw material powder. Yes, for example, from 1 kg up to 3
Rods can be made from raw material weights up to 00 kg.

Further, according to the present invention, a silica glass body having the purity of the raw material powder is obtained. Specifically, the impurity metal element (Li, Na, K, Ca, Mg,
Each concentration of Ti, Cr, Fe, Ni, Cu) is 500 wt
When the ppb is not more than ppb, a silica glass body having a metal element concentration difference from the main raw material silica powder of 10 wtppb or less is obtained.

According to the present invention, not only can silica glass doped with a specific element be obtained without contaminating the electric furnace, but also rods having a wide range of small to large diameters or glass having a long dimension can be obtained. In addition, it is possible to produce from small quantities to large quantities. Therefore, it is possible to produce a 10 m rod and a fiber of several tens m in length from a 1 cm cylindrical body.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be illustratively described in detail below. However, the materials, shapes, analytical values, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples, unless otherwise specified. .

First, this embodiment will be briefly described according to the manufacturing procedure shown in FIG. A, Silica glass hollow body 1 consisting of a sheath-shaped hollow single tube
(Hereinafter referred to as “sheath tube”) and heat distortion removal treatment In the present invention, preferably, the diameter is 20 to 200 mm, and the wall thickness is 0.1 mm.
A sheath tube 1 having a length of 5 to 20 mm and a length of 1 to 10 m is prepared, and the sheath tube 1 is removed by heating, washed and dried.

B. Preparation of Silica Powder Raw Material and Heat Treatment As the type of silica powder 2, any one or more of natural quartz, synthetic quartz, synthetic cristobalite, and synthetic silica glass are used, and amorphous silica powder 2 is used. In this case, heat treatment of the silica powder in a hydrogen-containing atmosphere or a helium-containing atmosphere before melting is effective in reducing bubbles during melting.
The doping element is mixed after the above treatment. In this case, the mixing ratio between the doping powder and the main raw material silica powder is adjusted so that the concentration of the specific doping element in the manufactured silica glass rod becomes 0.1 to 5 wt%. It is good to set. The particle size of the silica powder is preferably from 10 to 1000 μm. Below this, a large amount of bubbles are contained in the fused silica glass body 3. Above this, it is not uniform at the time of melting or it is difficult to remove air bubbles.

C. Filling of silica powder 2 into sheath tube 1 When crystalline silica is used as the main raw material silica powder 2, silica glass powder 2a is put in the lower end portion of the hollow body 1 and then gradually crystallized. Add powder with an increased ratio of crystalline powder such as powder. The filling length of the silica glass powder 2a at the lower end must be longer than the soaking length of the cylindrical electric furnace used for melting. Do not put the silica glass powder 2a at the tip,
When the crystal powder 2b is suddenly added and the temperature is raised in the electric furnace, the crystal powder 2b rapidly expands at the α-β transition temperature of the crystal, and the hollow body 1
Destroys. When all of the main raw material powder is made of amorphous silica, the same type of silica glass powder 2 may be sequentially filled from the tip portion.

D, Melting and Transparent Vitrification Using a Cylindrical Electric Furnace 4 The inside of the sheath tube 1 filled with the silica powder 2 is evacuated to 1 KPa or less, and the sheath tube 1 is introduced into the cylindrical electric furnace 4. The zone melting and the rod drawing are performed by controlling the feeding speed of the silica glass 7 melted by the cylindrical electric furnace 4 and the feeding speed.
A transparent rod-shaped silica glass 7 is obtained. It is preferable that the diameter of the transparent rod-shaped silica glass 7 formed in this way is not more than の of the diameter of the hollow sheath tube 1. The electric furnace was a cylindrical electric furnace having a high-purity graphite heater and a stainless steel jacket.
Is used.

Next, an embodiment based on the manufacturing procedure will be described. <Example 1: Manufacturing method of non-doped rod> A, Preparation of sheath tube 1 After preparing a cylindrical sheath tube 1 having a diameter of 130 mm, a wall thickness of 3 mm, and a length of 3 m using high-purity synthetic silica glass, a sheath tube 1 was prepared. Is subjected to a strain removal treatment by heating at 1050 ° C. for 10 hours in an electric furnace, followed by washing with a 10 wt% aqueous solution of hydrogen fluoride and drying treatment.

B, Preparation of Natural Quartz Powder Natural quartz powder was prepared in a particle size range of 50 to 300 μm and 10 μm.
Less than 0.1 wt% powder was adjusted. Next, this was subjected to a high-purity heat treatment at 1000 ° C. for 10 hours in a chlorine gas-containing atmosphere.

C, Preparation of Synthetic Silica Glass Powder The synthetic silica glass powder obtained by the sol-gel method was prepared by adding a particle diameter of 50 to 500 μm
m.

D. Loading and Filling of Silica Powder into Sheath Tube 1 As shown in FIG. 2, about 1 kg of synthetic silica glass powder 2a is charged into the tip, and then natural quartz: synthetic silica glass =
1: 2 mixture powder 2a ₁ was charged with about 1Kg (weight ratio), further, natural crystal: synthetic silica glass = 1: The mixed powder 2a ₂ 1 was charged with about 1Kg, furthermore, the natural lens : synthetic silica glass = 2: the powder mixture 2a ₃ 1 placed about 1Kg, finally, was charged with about 45Kg natural quartz powder 2b. As a result, the synthetic silica glass powder layer 2a was 12 cm,
Each of the layers of the mixed powder 2a ₁ , the mixed powder 2a ₂ , and the mixed powder 2a ₃ has a length of 6 cm, and the total of these layers is larger than the soaking length (10 cm) of the cylindrical electric furnace as shown in FIG. I was able to do it.

E, Melt and Transparent Vitrification Using a Cylindrical Electric Furnace The inside of a sheath tube filled with silica glass powder was
Of vacuum. The above-mentioned sheath tube containing powder was slowly inserted from the upper portion of the cylindrical electric furnace to be melted.

F, Production of Transparent Rod-Shaped Silica Glass 7 By controlling the feeding speed of the sheath tube 1 into the cylindrical electric furnace 4 and the pulling speed of the silica glass melted by the cylindrical electric furnace 4, The following three types of transparent rod-shaped silica glass 7 were manufactured while controlling the ratio of the diameter of the sheath tube 1 to the diameter of the rod-shaped transparent silica glass 7 to be 以下 or less. Diameter φ40mm, length 1m, 10 pieces (total 27.6Kg) Diameter φ20mm, length 1m, 10 pieces (total 6.9Kg) Diameter φ10mm, length 1m, 10 pieces (total 1.7Kg) Total 37Kg MF = ( 45 + 4) /37=1.3 (approximately) However, MF means a material factor.

Evaluation of Physical Properties The bubbles were at the same level as that of Heralux-E (trade name, manufactured by Shin-Etsu Quartz Co., Ltd.), and the total cross section of the bubbles existing at 100 cm ³ was 0.88 mm ² . However, the measurement method is DIN5
8927 (1970). Dimensional accuracy Diameter φ40mm φ20mm φ10mm Radial circumferential runout ± 0.1 ± 0.05 ± 0.02 Tolerance (mm) Radial circumferential runout ± 0.2 ± 0.1 ± 0.05 Tolerance (mm) Surface condition Is very smooth without scratches.

Impurity Analysis Table 1 shows the highly purified natural quartz powder before melting and the impurity concentration after melting and vitrification.

[0043]

[Table 1]

From this table, it can be seen that the high purity of the raw material powder is well preserved even after vitrification. However, Li, M
g and Ti were determined by ICP mass spectrometry, and Na, K, C
a, Cr, Fe, Ni, and Cu were measured by graphite furnace heating atomic absorption spectrometry.

<Comparative Example 1> Toshio Kagami, Akira Hayashi (1991), an electric melting molding furnace similar to the furnace shown in FIGS. The experiment was conducted by the electric heating melting direct drawing method. This electric melting furnace is manufactured by Heraus Co., Ltd. As shown in FIG. 3, a natural crystal powder 11 is put into a furnace 13 around which a heating element 12 is surrounded.
The rod-shaped silica glass 10 is drawn from the nozzle 14 when the quartz powder 11 is melted in the inside. A, Preparation of natural crystal powder 11 The same powder as in Example 1 was used. B, Loading of Natural Crystal Powder 11 into Electric Melting Molding Furnace 13 A total of about 100 kg of natural crystal powder 11 was charged. C, Production of Transparent Rod-Shaped Silica Glass 10 Only a transparent rod-shaped silica glass 10 having the following one dimension was produced. φ40mm, length 1m, 20 pieces (total about 55kg) MF = 100/55 = 1.8 (approximate)

The silica glass 10 thus produced
When the physical properties of the sample were evaluated, the content of bubbles was larger than that of Heralux-E, and was significantly larger than that of Example 1. And the total cross-sectional area of the foam existing in 100 cm ³ is 5 to 10 mm
^{Was 2} . As for the dimensional accuracy, the first embodiment is as follows.
About one digit worse than. Radial circumferential run-out tolerance (mm) ± 0.2 Radial circumferential run-out tolerance (mm) ± 0.4 The surface condition is often scratched by the nozzle.

As shown in Table 1, the results of the impurity analysis show that the amount of the impurity metal elements (Li, Na, K, Ca, and Mg) increased largely, and this is presumed to be due to impurity contamination from the refractory material of the furnace. <Example 2: Manufacturing method of sputtering target material> Next, a manufacturing method of a sputtering target material will be described. A, Production of sheath tube 1 A silica glass sheath tube 1 having a diameter of 150 mm, a wall thickness of 4 mm and a length of 2 m was prepared. (Contents about 35,000cm
³ ) B, Thermal distortion removal treatment of the sheath tube 1100 ° C in the cylindrical electric furnace 4 shown in FIG.
A strain removal treatment is performed by heating for 20 hrs, and a washing treatment and drying are performed with a 5 wt% aqueous hydrogen fluoride solution. C, Adjustment of natural quartz powder Natural quartz powder was adjusted to a particle size of 10 to 100 μm. next,
This powder is heated at 1000 ° C. for 20 hours in an atmosphere containing chlorine gas.
Heat and purify by heating, and remove this powder by 1 wt.
It was washed with a% hydrogen fluoride aqueous solution and dried. D, titanium oxide powder (Tio ₂₎ Adjustment purity 99.99 wt% or more, using the Tio ₂ powders having a particle size of 10~100μm range. E, Mixing of natural quartz powder and titanium oxide Uniform mixed powder 2 by mixing titanium oxide powder (TiO ₂ ) with natural quartz powder at a predetermined ratio in a silica glass V-type mixer.
Create b. Incidentally, Tio ₂ powders mixed compounding ratio of the Sio ₂ powder was set to 2 wt%. F, Preparation of Synthetic Silica Glass Powder 2a Synthetic silica glass powder prepared by sol-gel method
It was adjusted to 1000 μm.

G, Charge and Filling of Silica Powder into Sheath Tube 1 About 2 kg (filled layer 10 mm) of synthetic silica glass powder is charged into the tip, and then natural quartz powder: synthetic silica glass powder = 1: About 2 kg (filled layer 10 mm) of 1 (weight ratio) mixed powder 2a ₂ is charged, and finally about 40 kg of natural quartz and titanium oxide mixed powder (main raw material silica glass powder 2b) as main raw materials is input. . H, Melting and Transparent Vitrification Using a Cylindrical Electric Furnace 4 After the inside of the sheath tube 1 is evacuated to a degree of vacuum of 100 Pa or less, the feeding speed of the sheath tube 1 into the cylindrical electric furnace 4 and the cylindrical electric furnace 4 to control the pulling speed of the fused silica glass 7 so that the ratio of the diameter of the sheath tube 1 to the diameter of the transparent silica glass body 7 is 以下 or less. The silica glass 7 is manufactured.

The titanium-doped silica glass 7 has the following two dimensions. Diameter φ100mm, length 1m, 1 piece (about 17Kg) Diameter φ50mm, length 1m, 5 pieces (about 21Kg) Total 38Kg MF = (40 + 4) /38=1.2 (approximate)

Evaluation of Physical Properties Table 2 of the impurity analysis shows the impurity concentrations of highly purified natural quartz powder before melting and silica glass after melting and transparency.

[0051]

[Table 2]

From this table, it can be seen that the purity of the raw material powder is well preserved even after vitrification. It should be noted that the transparent silica glass 7 can be formed by a similar production method using a main raw material silica mixed with ceramics such as alumina, mullite, and zirconia instead of the titanium oxide powder (TiO ₂ ).

<Comparative Example 2> Next, the following experiment was conducted using the same electric melting molding furnace as the prior art furnace shown in FIG. A, Preparation of Natural Quartz Powder and Titanium Oxide The same processing as in Example 2 is performed to prepare a mixed powder in which natural crystal powder is mixed with 2 wt% of titanium oxide (TiO ₂ ). B, Next, charging of the mixed raw material powder into the electric melting molding furnace In this comparative example, a total of 44 kg of the mixed raw material powder was charged. C, Manufacture of Titanium-Doped Silica Glass While drawing out from the nozzle 14 of the furnace 13, only one of the following dimensions was prepared. Diameter φ100mm, length 1m, 1 piece (about 17Kg) MF = 44/17 = 2.6 (approximate)

Evaluation of Physical Properties The results of impurity analysis are shown in Table 2 as shown in Table 2.
i, Na, K, Ca, Mg) and Fe were greatly amplified, and it is estimated that impurities were contaminated from the refractory material of the furnace. <Example 3: Production method using amorphous silica powder> When natural quartz powder cannot be used due to high purity restrictions, it can be produced using amorphous synthetic silica powder. A, Preparation of a sheath tube 1 For example, a sheath tube made of high-purity synthetic silica glass having a diameter of 60 mm, a wall thickness of 1.5 mm, and a length of 2 m was prepared (content of about 56
After 00 cm ³ ), the sheath tube was subjected to a heat treatment at 1100 ° C. for 10 hours in an electric furnace to remove the thermal strain. Next, washing and drying with a 5 wt% hydrofluoric acid aqueous solution are performed.

B, Preparation of High-Purity Synthetic Silica Glass Powder High-purity synthetic silica glass powder is prepared from silicon tetrachloride as a raw material by an oxyhydrogen flame hydrolysis method. Table 3 shows the impurity analysis values of the silica powder. The particle size was 10 to 100 μm.

[0056]

[Table 3]

C, Atmosphere Heat Treatment of High Purity Synthetic Silica Glass Powder In the electric heating furnace 4, a heat treatment was performed at 800 ° C. for 3 hours in an H ₂ gas atmosphere. D. Filling and charging of silica powder into sheath tube 1 Only 7 kg of synthetic silica glass powder is charged.

E. Melting and Transparent Vitrification Using a Cylindrical Electric Furnace 4 After the inside of the sheath tube 1 was evacuated to 10 Pa or less, the feeding speed of the sheath tube 1 into the cylindrical electric furnace 4 and the cylindrical electric furnace 4 By controlling the drawing speed of the silica glass melted by the furnace 4, the ratio of the diameter of the sheath tube 1 to the diameter of the transparent silica glass 7 is reduced to 1/2.
A high-purity transparent synthetic silica glass rod having the following dimensions is prepared while controlling as follows. Diameter φ10mm, length 11m, 10 pieces (total 1.8Kg) Diameter 5mm, length 11m, 50 pieces (total 2.2Kg) Diameter 1mm, length 11m, 100 pieces (total 0.2Kg) Diameter φ10 ~ 5mm, length 11m, 2 pieces of Taelot lot (0.2kg in total) 4.4kg MF = 7 / 4.4 = 1.6 (approximate)

Evaluation of Physical Properties The transparent silica glass 7 thus formed preserves the high purity of the raw material powder as apparent from Table 3 of the impurity analysis. The total cross-sectional area of the bubbles existing at 100 cm ³ was 0.2 mm ² .

<Comparative Example 3> A transparent vitrification treatment was performed without heating the high-purity synthetic silica glass powder in the H ₂ gas atmosphere in Example 3. And the physical property evaluation of the transparent silica glass 7 thus formed is
First, the total cross-sectional area of the bubbles existing at 100 cm ³ was 5.4 mm ² . From this, the effect of the H ₂ gas atmosphere treatment is understood.

[Brief description of the drawings]

FIG. 1 is an operation diagram showing a manufacturing procedure of the present embodiment.

FIG. 2 is an enlarged view of a lower end of a sheath tube of FIG. 1;

FIG. 3 is an electric melting furnace according to the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow silica glass 2 Raw material silica powder 2a Amorphous silica powder 2b Quartz powder 4 Cylindrical electric furnace

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Masanori Suzuki 88 Kawakubo, Kanaya, Tamura-cho, Koriyama-shi, Fukushima Shin-Etsu Quartz Co., Ltd. Koriyama Plant (56) References JP-A-2-283015 (JP, A) JP JP-A-3-1528 (JP, A) JP-A-62-171935 (JP, A) JP-A-61-286239 (JP, A) JP-A-58-151336 (JP, A) JP-A-3-187934 (JP) JP-A-4-325431 (JP, A) JP-A-3-177568 (JP, A) JP-A-62-29144 (JP, A) JP-A-64-37425 (JP, A) 4-292436 (JP, A)

Claims (14)

(57) [Claims] 1. A method for producing a silica glass body or a non-doped silica glass body doped with a metal element or a metal element compound, comprising: a hollow silica glass body having a single-tube structure having one end sealed; One or a plurality of small-diameter inner tubes are inserted into the tube to form an integrated silica glass hollow body in which one end of these tubes is fused and sealed, and then at least a tip of the sealed end side of the hollow silica glass body. A heated body is prepared by filling amorphous silica powder into the raw material and further filling the main raw material silica powder. The inside of the heated body is gradually heated and melted by zone melting upward from the lower end side while reducing the pressure. In addition, in the filling of the powdery material into the filling area, at the lower end portion of the filling area where heating is started by zone melting, a powdery material mainly composed of amorphous silica powder is located. Undoped or production method of doped silica glass body main material silica powder whose main component is quartz powder other crystalline silica powder is characterized by performing the filling so as to be located in portions. 2. A method for producing a silica glass body or a non-doped silica glass body doped with a metal element or a metal element compound, comprising: a hollow silica glass body having a single-tube structure having one end sealed; One or a plurality of small-diameter inner tubes are inserted into the tube to form an integrated silica glass hollow body in which one end of these tubes is fused and sealed, and then at least a tip of the sealed end side of the hollow silica glass body. With amorphous silica powder, and further above
A main raw material silica powder mainly composed of quartz powder or other crystalline silica powder is filled, and then the inside of the hollow silica glass body filled with the raw material powder is depressurized while a vertical portion is formed from the tip of the hollow silica glass body. Characterized in that a silica glass body is obtained by an electric heating and melting method by inserting the silica glass body into an upper portion of a cylindrical electric furnace, or a high purity silica glass body. 3. A quartz powder or other crystalline silica powder as a main component.
The filling length of the powdery material containing the amorphous silica powder as a main component up to the filling position of the main raw material silica powder is larger than the soaking length of the zone heating means. Production method. 4. An amorphous silica powder is first filled from the sealed end of the hollow silica glass body, and then a mixed powder of the amorphous silica powder and the crystalline silica powder is filled, and then the crystalline main raw material silica is filled. The method for producing a silica glass body according to claim 1, wherein the powder is filled. 5. A main component of the main raw material silica powder is at least one kind of crystalline silica of natural crystal powder, synthetic crystal powder, and synthetic cristobalite powder, and has a particle size of 10 to 100.
The method for producing a silica glass body according to claim 1, wherein the content ratio of fine particles having a range of 0 µm and less than 10 µm is 0.1 wt% or less. 6. The method according to claim 1, wherein the reduced pressure atmosphere is a vacuum of 1 KPa or less. 7. A method for producing a silica glass body or a non-doped silica glass body doped with a metal element or a metal element compound, comprising: a hollow silica glass body having a single-tube structure, one end of which is sealed; One or a plurality of small-diameter inner tubes are inserted into the tube to form an integrated silica glass hollow body in which one end of these tubes is fused and sealed, and then at least a tip of the sealed end side of the hollow silica glass body. With amorphous silica powder, and further above
Prepare a body to be heated filled with a main raw material silica powder mainly composed of quartz powder or other crystalline silica powder, and gradually form a zone melt upward from the lower end side while the inside of the body to be heated is in a reduced pressure atmosphere. While heating and melting, the feed rate of the heated body into the zone heating means and the pulling speed of the silica glass melted by the zone heating means are controlled to control the diameter of the heated body and the fused silica glass body. A method of producing a non-doped or doped silica glass body, characterized in that the ratio of the diameters of the particles is 1/2 or less. 8. A method for producing a silica glass body or a non-doped silica glass body doped with a metal element or a metal element compound, comprising: a hollow silica glass body having a single-tube structure, one end of which is sealed; One or a plurality of small-diameter inner tubes are inserted into the tube to form an integrated silica glass hollow body in which one end of these tubes is fused and sealed, and then at least a tip of the sealed end side of the hollow silica glass body. With amorphous silica powder, and further above
The main raw material mainly composed of quartz powder and other crystalline silica powder
A heated body filled with lica powder is prepared, and while the inside of the heated body is reduced in pressure atmosphere, gradually heated and melted by zone melting upward from the lower end side, and the meat in the filled area portion of the heated body is prepared. A method for producing a non-doped or doped silica glass body, characterized in that the heated body has a thickness set within 0.5 mm to (hollow body outer diameter) × 10% or less. 9. A method for producing a silica glass body or a non-doped silica glass body doped with a metal element or a metal element compound, comprising: a hollow silica glass body having a single-tube structure, one end of which is sealed; One or a plurality of small-diameter inner tubes are inserted into the tube to form an integrated silica glass hollow body in which one end of these tubes is fused and sealed, and then at least a tip of the sealed end side of the hollow silica glass body. A heated body is prepared by filling amorphous silica powder into the raw material and further filling the main raw material silica powder. The inside of the heated body is gradually heated and melted by zone melting upward from the lower end side while reducing the pressure. as well as, a non-doped young and performing heat treatment of the main raw material silica powder to be filled into the filling zone in advance hydrogen-containing atmosphere or a helium containing atmosphere Ku the production method of doped silica glass body. 10. One or a plurality of small-diameter inner tubes are inserted into a hollow silica glass body having a single-tube structure having one end sealed, or one or a plurality of small-diameter inner tubes are inserted into a large-diameter outer tube. Then, an amorphous silica powder is filled into at least the tip on the sealing end side of the hollow silica glass body, and further the upper portion thereof is filled.
A heated body filled with a main raw material silica powder made of a silica powder obtained by mixing a doping compound is prepared, and the inside of the heated body is gradually heated in a zone melting upward from a lower end side while a reduced-pressure atmosphere is set. While melting, a substantially bubble-free silica glass body is obtained by controlling the feeding speed of the object to be heated into the zone heating unit and the pulling speed of the silica glass melted by the zone heating unit. Of producing a doped silica glass body. 11. A method for manufacturing a sputtering target material or a nonlinear optical material containing silica glass as a main component, wherein one or a plurality of hollow silica glass bodies having a single-tube structure with one end sealed, or a large-diameter outer tube. To form an integrated silica glass hollow body in which one end of these tubes is fused and sealed, and a non-silica glass hollow body is provided at least at the end on the sealed end side.
A crystalline silica powder is filled, and an oxide of each of the elements of atomic numbers 5, 6, 13 to 15, and 22 to 32 is further added to the upper part thereof,
A body to be heated filled with silica powder, which is a main raw material mixed with at least one doping compound of chloride, iodide, nitrate, and carbonate, is prepared. While gradually heating and melting in the zone melting upward, the specific doping element by controlling the feeding speed of the object to be heated into the zone heating means and the pulling speed of the silica glass melted by the zone heating means A method for producing a sputtering target material or a non-linear optical material, characterized in that a substantially bubble-free silica glass body is obtained by doping the target. 12. The sputtering target according to claim 10, wherein the mixing ratio of the doping compound and the main raw material silica powder is set such that the concentration of the specific doping element in the manufactured silica glass body becomes 0.1 to 5 wt%. Method for manufacturing a material or a nonlinear optical material. 13. A method for producing a fluorescent luminous body, a laser oscillating body, and a nonlinear optical body containing silica glass as a main component, comprising: a hollow silica glass body having a single-tube structure with one end sealed, or a large-diameter outer tube. One or a plurality of small-diameter inner tubes are inserted, and one end of these tubes is fused and sealed to form an integrated silica glass hollow body.
Main raw material which is filled with crystalline silica powder and further mixed with at least one doping compound of oxides, chlorides, iodides, nitrates and carbonates of the elements having atomic numbers 57 to 71 in the upper part thereof A heated body filled with silica powder is prepared, and while the inside of the heated body is gradually heated and melted in a zone melting upward from the lower end while the inside of the heated body is in a reduced-pressure atmosphere, the inside of the zone heating means of the heated body is introduced. A fluorescent emitter, a laser oscillator, or a non-linear optics, wherein a substantially bubble-free doped silica glass body is obtained by controlling the feed rate of the silica glass melted by the zone heating means. How to make the body. 14. The fluorescent luminous body according to claim 13, wherein the mixing ratio of the doping compound and the main raw material silica powder is set such that the concentration of the specific doping element in the manufactured silica glass body becomes 0.1 to 5 wt%. , A laser oscillator, or a method for manufacturing a nonlinear optical body.