JPH0457608B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a bismuth-silicon based amorphous compound and a method for producing the same, and more particularly to a new bismuth-silicon based material that has not been described in any literature and a method for producing the same. Research into oxide-based ceramics and their single crystals, mainly consisting of bismuth oxide (Bi ₂ O ₃ ), has been actively conducted in line with the recent development of the electronics field, with particular focus on opto-electrical and audio-electrical fields. It has been actively researched as a conversion element material for atmospheric gas-electricity, photoacoustic signals, X-ray spectroscopy, etc., and as a catalyst.
As a stable compound of Bi ₂ O ₃ and SiO ₂ , 2,3
Only a few types of crystalline forms are described in the literature, and research into single crystallization of these compounds is actively conducted, but no research has been conducted on them as amorphous compounds. . The present invention is a newly synthesized bismuth-silicon-based amorphous compound that has been completely unknown in the past.In other words, the present invention synthesizes (SiO ₂ ) _X. (Bi ₂ O ₃ ) _1-X (However,
A novel bismuth-silicon amorphous compound having a composition of 1>x>0) and (SiO ₂ ) _X and (Bi ₂ O ₃ ) _1-X
The present invention relates to a method for producing a bismuth-silicon amorphous compound, which is characterized by heating and melting a mixture (1>x>0) and then ultra-quenching the mixture. The manufacturing method of the present invention will be explained below. The raw material used in the present invention is a mixture of bismuth oxide and silicon oxide, and its composition ratio is (SiO ₂ ) _X・(Bi ₂ O ₃ ) _1-X (1>x>0) . A raw material mixture having the above composition ratio is heated and melted, and then cooled extremely rapidly. The heating and melting may be carried out at a temperature higher than the temperature at which these raw material mixtures are sufficiently melted, preferably 50 to 200°C or higher than the melting temperature, particularly preferably 80 to 200°C.
Heat at a temperature higher than 150℃. There are no particular restrictions on the atmosphere during heating, and heating is usually performed in air. Next, the melt of the raw material mixture is ultra-quenched. At this time, it is extremely important to perform ultra-rapid cooling, and only then can a new amorphous compound be obtained. Ultra-rapid cooling is usually performed at a cooling rate of about 10 ⁴ to ^{10 6} °C/sec. A wide variety of methods can be used for this ultra-quenching as long as it can cool at the above-mentioned cooling rate.A typical method is to spray the melt of the raw material mixture onto the surface of a roll rotating at high speed to form a liquid state. A typical example is the method of assimilation based on the atomic arrangement of The means will be explained in more detail below. An example of a typical apparatus used in carrying out the method of the present invention will be described below with reference to the drawings. FIG. 7 is a front view of the quenching device, in which 1 is a rotating roll for quenching, 2 is a tube with a nozzle for heating the raw material,
3 indicates a dielectric heating coil. FIG. 8 is a diagram showing the tube support, 4 is a needle valve, 5
6 indicates a blow air inlet, 6 indicates a cooling water outlet, and 7 indicates a cooling water inlet. The inside of this support can be cooled with cooling water, and is equipped with a post-adjustment mechanism 3 for the gap between the roll surface and the tube nozzle opening, and a rectification eye for uniformly extruding the raw material melt. A plate 9 is attached to the tip. Fig. 9 is a drawing of a stable quenching type air-cooled roll in which a fan is installed inside the roll and an air suction port is provided at the end of the roll surface for the purpose of efficiently quenching and air-cooling the roll itself. Its front view, B is a side sectional view, and C is an explanatory diagram of the shape of the slit hole.
FIG. 10A shows a countercurrent blow-off nozzle for preventing wind vortices generated by rotation on the roll surface, and FIG. Preferably, all of these nozzles are made of quartz tubes. Figure 11 shows the tube and nozzle shapes for heating the raw material.
and E are slit nozzles with an inclined angle. First, a raw material mixture having a predetermined composition is stored in a tube having a nozzle for blowing out the melt. The tube is made of a material sufficiently durable under high temperature oxidizing atmosphere conditions, preferably of platinum, platinum-rhodium, iridium, silicon nitride, boron nitride, or the like. The material of the parts not in direct contact with the raw material melt may be high melting point ceramics, glass, or metal. The shape of the nozzle opening is appropriately determined depending on the target product; for example, a round shape is used for thin linear materials, and a slit-shaped mouth is used for wide products. The raw material mixture stored in the tube is then heated to a temperature above its melting point to form a melt, and then the melt is blown out at a constant gas pressure onto the roll surface that is rotating at high speed and is rapidly cooled on the roll surface. . At this time, the blowing angle of the raw material melt between the nozzle opening and the roll surface may be perpendicular to the roll surface if the width of the target compound is approximately 3 mm or less, and if the width is approximately 3 mm or more, it may be perpendicular to the roll surface. The blowout angle is between 0° and 45°. Although it is possible to incorporate a mechanism for setting a predetermined angle into the device itself, it is preferable to use means for machining the nozzle. The method of heating the raw material mixture is not particularly limited, but it is usually carried out in a furnace equipped with a heating element, a dielectric heating furnace, or a condensing heating furnace. The raw material mixture is heated and melted by this heating, and the temperature of the raw material melt at this time is preferably about 50 to 200°C higher than its melting point, preferably about 80 to 150°C. At this time, if the temperature is not much higher than the melting point, there is a risk that the melt will cool and solidify near the nozzle while being blown out onto the roll surface, and conversely, if the temperature is too high, it may interfere with rapid cooling on the roll surface. occurs. The pressurized gas used to blow out the melt onto the roll surface is preferably an inert gas, such as argon, nitrogen, helium, etc.
Dry compressed air is preferred since it may reduce the melt raw material. The gas pressure depends on the size of the nozzle opening, but is usually 0.1 to 2.0 Kg/cm2, preferably 0.5 to 2.0 kg/ ^cm2 .
It is ^about 1.0Kg/cm2. Also, the distance between the nozzle opening and the roll surface when blowing out the raw material melt is 0.01 to 1.0 mm.
The thickness is good, particularly preferably about 0.05 to 0.5 mm. If it is smaller than 0.01 mm, the puddle amount will be very small and a uniform material cannot be obtained. If it is larger than 1.0 mm, the puddle amount will be excessive or the puddle thickness formed by the interfacial tension of the composition melt will be exceeded. In this case, there may be a tendency for a paddle to be difficult to form. The material of the roll is copper and its alloy with good thermal conductivity, the above materials with a hard chrome plating layer, steel, stainless steel, etc., and the speed of the roll is 5 m/sec to 35 m/sec, preferably 10 m/sec to
By rapidly cooling at 20 m/sec, the desired amorphous compound material of high quality can be obtained. In this case, if the peripheral speed of the roll is 5 m/sec or less, it is not very preferable because it tends to be difficult to become amorphous. When the circumferential speed is greater than 35 m/sec, the shape of the target material obtained becomes extremely thin, and all of it becomes scaly or fine powder-like. Although it is possible to produce the compound of the present invention under reduced pressure to high vacuum or in an inert gas atmosphere as the atmosphere in which the liquid raw material is blown onto the rotating roll surface, reduction of the raw material melt at high temperatures occurs and the composition A decrease in oxygen atoms in the atoms occurs,
The resulting material may be colored purple or black. However, it is physically a compound of the present invention and can be used in a reconstituted state. Furthermore, when heating and melting the raw material mixture in the tube, it is necessary to completely melt the mixture. However, before the mixture is completely molten, some of the molten material may flow out from the nozzle tip, so it is necessary to locally cool the nozzle tip to prevent the melt from flowing out. preferable. A typical means for locally cooling the nozzle is to blow a cooling gas onto the tip of the nozzle, and the gas may be an inert gas such as argon, helium, or nitrogen, but dry, cold compressed air is preferred. The novel amorphous compound material according to the present invention is usually
It is a very fragile material with a thickness of about 50 to 10 μm. For this reason, it is preferable to maintain a state in which stress is not applied to the material as much as possible after it is rapidly cooled and solidified on the roll surface. The cause of the stress addition is the large turbulent flow in the air layer on the roll surface caused by the wind phenomenon caused by the roll rotation in the atmosphere. It is necessary to prevent this turbulent flow, and for this purpose and to improve the adhesion between the molten raw material mixture to be rapidly cooled and the roll surface, a countercurrent blowout nozzle is installed to prevent wind blowing. be fixedly installed. In the latter case, the turbulent flow generated inside the roll due to rotation of the roll is absorbed into the roll through a variable-diameter air inlet provided at the end of the roll surface, and is discharged from the front of the roll axis. By moving the melt into the inside, the molten material is pressed against the roll surface, and the roll itself can be cooled by air blowing and movement.
Further, in order to maintain the dimensional uniformity of the obtained material, if grooves for cutting the material are provided on the roll surface at right angles to the direction of rotation, the material can be cut to a constant length and a cut material can be obtained. The atomic arrangement structure of the bismuth-silicon compound of the present invention varies greatly depending on the raw material mixing ratio, and can be roughly classified into three types. First, 0.4≦x<
In case of 1, 100% amorphous compound is 0.15
When ≦x<0.4, a compound of a small amount of δ-Bi ₂ O ₃ polycrystalline phase and an amorphous compound, and when 0<x<0.15, α
−Bi ₂ O ₃ and γ−Bi ₂ O ₃ polycrystalline phase and ( _{SiO 2} )
(Bi ₂ O ₃ ) An amorphous compound containing _{a 1-X} solid solution polycrystalline phase is obtained. The production range of the compound of the present invention is shown in FIG. Further, when the rotational speed of the roll changes, that is, the circumferential speed changes in the range of 5 m/sec to 35 m/sec, there is no significant difference in the structural changes of the material obtained with each composition change. This is shown in Figure 2 A to C. In addition, Fig. 2 A _is (Bi ₂ O ₃ ) _1-X・(SiO ₂ )
is 0.25, and the same figure (b) shows the case where x is 14.29 and the circumferential speed is 17.27 m/sec, and the same figure (c) shows the case where x is 0.33 and various circumferential speeds. As a means of identifying the structure of the material obtained in the present invention, the presence or absence of crystallinity and structural analysis were performed using X-ray diffraction and a polarizing microscope, and a scanning electron microscope was used for a very small portion. A photograph of a typical amorphous compound of the present invention in Test No. 30 of the reprinted example is shown in Figure 3, and a scanning electron micrograph (24000x) of Test No. 16 is shown in Figure 4.
As shown in the figure. Similarly, FIG. 5 shows the results of differential thermal analysis. Moreover, the infrared absorption spectrum is shown in FIG.
In Figure 6, A is for Test No. 30 and B is for Test No. 8. EXAMPLES The present invention will be specifically described below with reference to Examples. Examples Bi ₂ O ₃ (purity 99.9%) and SiO ₂ (purity
99.9%) was uniformly mixed at a predetermined blending ratio, calcined at 850°C for 30 minutes, taken out, allowed to cool, and ground and mixed again to obtain a composition raw material. This composition raw material was filled into a platinum tube (ψ10 mm x length 150 mm), which was placed inside a dielectric heating coil. Dielectric heating is oscillation tube fiber voltage 13V, anode voltage 10KV, grid current 120
This was carried out at ~150 mA and an anode current of 1.2 to 1.8 A to melt the raw materials, which were then blown onto the surface of a rotating roll with dry compressed air to rapidly cool them. Tables 1 and 2 show the condition values and the obtained materials. Test Nos. 1 to 20 are conditions that satisfy the requirements of the present invention, and Test Nos. 21 to 29 are unsuitable conditions.

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【table】 [Brief explanation of the drawing]

FIG. 1 is a drawing showing the composition range of the compound of the present invention,
Figure 2 shows its X-ray diffraction diagram, Figure 3 its differential thermal analysis diagram, and Figure 4 its infrared absorption spectrum. 5 and 6 are drawings showing examples of various apparatuses used in carrying out the method of the present invention, with FIG. 5 showing a front view of the quenching device, and FIG. 6 showing a longitudinal sectional view of the tube support.

Claims (1)

[Scope of Claims] A novel bismuth-silicon amorphous compound having a composition of 1(SiO ₂ ) _X ·(Bi ₂ O ₃ ) _1-X (where 1>X>0). 2 (SiO ₂ ) _X and (Bi ₂ O ₃ ) _1-X (However, 1>X>
1. A method for producing a bismuth-silicon amorphous compound, which comprises heating and melting the mixture of item 0) and then ultra-quenching the mixture. 3. The manufacturing method according to claim 2, characterized in that the ultra-rapid cooling is carried out at a rate of 3 10 ⁴ to 10 ⁶ °C/sec. 4. The manufacturing method according to claim 2, characterized in that the ultra-quenching is carried out by a solid contact liquid ultra-quenching method. 5. Pour the raw material mixture into a tube that has a blow-out nozzle with a slit-shaped, round, or oval hole at the bottom, and
The manufacturing method according to claim 2, which comprises heating and melting at a temperature higher than 200°C, and then blowing it onto the surface of a roll rotating at a circumferential speed of 5 to 35 m/sec to rapidly cool it. 6. It is made of a material that is stable in a high-temperature oxidizing atmosphere that is higher than the melting temperature of the raw material mixture, and only the tip of the nozzle is cooled with cooling gas so that the molten liquid of the raw material mixture does not drip from the tip of the nozzle unless necessary. 3. The manufacturing method according to claim 2, characterized in that the ultra-rapid cooling is carried out using a nozzle designed to obtain the desired results.