JP3344390B2 - Viscosity measurement method for green compacts - 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 measuring the viscosity of a green compact formed by pressing an amorphous glass powder or the like.

[0002]

2. Description of the Related Art In recent years, in the electronics industry, research and development of ceramic multilayer substrates and thick film materials capable of coping with high density of mounted components and circuit conductors, high frequency of signals, and the like have been actively conducted. In particular, a ceramic multilayer substrate formed by firing a mixed material containing an amorphous glass powder or a crystallized glass powder has a small relative dielectric constant and a small specific resistance.
Since simultaneous firing with a conductor material can be performed, it is possible to sufficiently cope with high density and high frequency.

In such a ceramic multilayer substrate, the physical properties of an oxide inorganic powder such as an amorphous glass powder and a crystallized glass powder greatly contribute to substrate characteristics and thick film characteristics.
Above all, the viscosity characteristics of amorphous glass powder greatly affect the sintering process and diffusion behavior of Ag conductor, etc.
This is an extremely important parameter in material design and process design.

[0004]

Generally, the viscosity of an oxide inorganic powder such as an amorphous glass powder has a viscosity of about 10 ¹⁰ Pa
A high viscosity region of S or higher is measured by a fiber drawing viscometer, and a low viscosity region of approximately 10 ⁴ Pa · S or lower is measured by a rotary viscometer (spherical viscometer). Then, particularly important 10 ⁴ to 10 ⁹ P in the sintering process
For the medium viscosity region of a · S, the viscosity is measured by a parallel plate pressure viscometer.

Hereinafter, a method of measuring the viscosity η using a parallel plate pressure viscometer will be described.

First, as shown in FIG. 22, an object (sample) 1 whose height H and volume V are accurately measured is placed on a quartz plate 2a fixed to a support table 3. Then
After being sandwiched by a quartz plate 2b fixed to the quartz rod 4, a constant load M is applied to the quartz rod 4 and the temperature inside the device 6 is increased by the heater 5, and the differential transformer (shown in FIG. (Omitted), the displacement (height H) of the DUT 1 is detected. Then, by extracting this displacement with time, the sample deformation speed dh / d of the DUT 1 is obtained.
Calculate t.

Next, the volume V of the measured object, the sample height H, and the sample deformation speed dh / dt obtained by the above-described method are shown in GENT.
Formula: η = 2πMGH ⁵ / 3V (dh / dt) (2πH ³ + V) (However, M: load, H: sample height, G: gravitational acceleration,
V: sample volume, dh / dt: sample deformation rate) to calculate the viscosity η of the DUT 1 (ANGENT, BR)
ITISH JOURNAL OF APPLIED PHYSICS VOL.11, FEBRUARY
1960). And this is done for each temperature,
A change in viscosity η with temperature, that is, a viscosity-temperature curve is derived.

However, in the above-described viscosity measurement using a parallel plate pressure viscometer, it is necessary to use a bulk sample as the DUT 1. In other words, the GENT formula is a viscosity conversion formula that is established when the DUT 1 can be assumed to be an incompressible fluid. For example, when the viscosity of an amorphous glass powder is to be measured, the amorphous glass powder is melted. It is necessary to use a sample (bulk sample) which is rapidly cooled and formed into a bulk.

As described above, according to the above-described method, the viscosity of a sample formed in a bulk shape can be measured. However, for a sample in a powder state that has a great influence on the material design and process design of a ceramic multilayer substrate or a thick film material. Cannot measure its viscosity.

The present invention has been made in view of the above-mentioned circumstances, and has as its object to measure the viscosity of a compact formed by pressing an inorganic powder with high accuracy. It is to provide a measuring method.

[0011]

That is, according to the present invention, the viscosity η of a green compact formed by press-molding an inorganic powder is defined as G
ENT formula: η = 2πMGH ⁵ / 3V (dh / dt) (2πH ³ + V) (However, M: load, H: sample height, G: gravity acceleration,
(V: sample volume, dh / dt: sample deformation rate) in a method for measuring the viscosity of a green compact, wherein a pre-calcined green compact is used for the measurement. And a method for measuring viscosity.

According to the method of measuring the viscosity of a green compact of the present invention, the particles of the inorganic powder are sufficiently necked by calcining the green compact in advance, so that the viscous behavior of the powder is reduced. The viscosity can be measured with high accuracy for a compact formed body that is very close to that of an incompressible fluid and that exhibits a viscous behavior very close to the powder state of various inorganic powders.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The method of measuring the viscosity of a green compact according to the present invention is as follows: The viscosity η of a green compact obtained by press-molding an inorganic powder such as an amorphous glass powder is determined by the GENT formula: η = 2πMGH ⁵ / 3V (dh / dt) (2πH ³ + V) (however, M: load, H: sample height, G: gravitational acceleration,
(V: sample volume, dh / dt: sample deformation rate), in which a green compact molded in advance and calcined under conditions such that the particles of the inorganic powder are sufficiently necked is used for the measurement. . In addition, this calcining
It may be carried out on a green compact or on an inorganic powder.

In the method for measuring the viscosity of a green compact according to the present invention, the inorganic powder may be one kind selected from the group consisting of amorphous glass powder, crystallized glass powder, and glass-ceramic composite powder. It is desirable to use an oxide inorganic powder. Above all, it is desirable to use amorphous glass powder as the inorganic powder. Amorphous glass powder is
Since it shows reversible properties to heating and cooling during calcination,
A relatively wide range of conditions can be applied to the calcination temperature, calcination time, heating rate, and the like.

In the method for measuring the viscosity of a green compact according to the present invention, it is preferable that the calcination is performed at a temperature lower than the softening temperature of the inorganic powder. That is, by calcining an inorganic powder such as an amorphous glass powder, a crystallized glass powder, and a glass ceramic composite powder at a temperature lower than its softening temperature (softening point) for a certain period of time and sufficiently necking the particles, thereby temporarily The viscous behavior of the green compact after firing can be made very close to that of the incompressible fluid.

Therefore, the measured value (or calculated value) of the sample volume and sample height of the calcined green compact and the measured value (or calculated value) of the sample deformation rate measured by a parallel plate pressure viscometer or the like are used as GENT.
By simply applying the formula, the viscosity of the compact can be measured with high accuracy.

The calcination is preferably carried out at a temperature of T-10 ° C. or higher, that is, a softening temperature minus 10 ° C. or higher, where T (° C.) is the softening temperature of the inorganic powder. In other words, when the calcination temperature is t, if calcination is performed in a range that satisfies the relationship of T−10 ≦ t ≦ T, the particles are sufficiently necked and the sample is not deformed due to the softening flow. The viscosity of the compact can be measured with high accuracy.

Next, the method for measuring the viscosity of a green compact according to the present invention will be described with reference to the flowchart of FIG. 1 as an example.

As shown in FIG. 1, first, an amorphous glass powder is prepared by a high-temperature melting method or a sol-gel method.
Next, the amorphous glass powder is mixed and dispersed together with a vehicle component including an organic binder (or an aqueous binder), a solvent, and the like. Then, the obtained mixture is press-molded to produce a green compact formed of amorphous glass.

Next, the green compact is calcined at an appropriate temperature to sufficiently neck the powder particles. here,
An appropriate calcination temperature is a temperature at which the particles of the amorphous glass powder are sufficiently necked, and is desirably lower than the softening temperature, more desirably lower than the softening temperature and higher than the softening temperature minus 10 ° C. .

That is, in the present invention, calcining may be performed under conditions such that powder particles are sufficiently necked.
The calcination time, the heating rate, and the like are not particularly limited. For example, in the case of a green compact formed of an amorphous glass powder, the calcining temperature can be appropriately selected in a range of about 30 to 90 minutes, and the heating rate can be appropriately selected in a range of about 1 to 10 ° C./min.

Then, the sample height H and the sample volume V of the green compact after calcination were measured, and FIG.
By using a parallel plate pressure viscometer as shown in FIG. 2 and gradually increasing the temperature, the sample height H of the green compact when a load M was applied was measured over time. From this, the sample deformation speed dh / dt is calculated.

Thereafter, the obtained sample height H and sample volume V
By applying the sample deformation rate dh / dt to the above-mentioned GENT equation, the viscosity η (viscosity-temperature curve) of the green compact is derived.

As described above, by calcining the green compact before applying it to the parallel plate pressure viscometer, the viscosity η of the amorphous glass powder used for the ceramic multilayer substrate, the thick film material, etc. Further, the viscosity-temperature curve can be measured with high accuracy. That is, it becomes possible to evaluate the viscosity of the green compact which exhibits a viscous behavior very close to the powder state of the amorphous glass powder.

Although the method for measuring the viscosity of a green compact according to the present invention has been described above for an amorphous glass powder, the present invention is limited to the measurement of the viscosity of a green compact formed from this amorphous glass powder. Not something.

For example, crystallized glass powder, glass ceramic composite powder, and other inorganic powders
By similarly applying, the viscosity η can be derived with high accuracy, and further, the viscosity-temperature curve can be prepared with high accuracy. However, when the present invention is applied to crystallized glass powder or glass-ceramic composite powder, the rate of temperature rise is preferably as low as possible, for example, 1 to 5 ° C./min. This is because nuclei of precipitated crystals can be sufficiently formed.

In the present invention, the green compact after calcination exhibits a viscous behavior very close to that of an incompressible fluid. However, depending on the residual state of the binder in the green compact, the viscous behavior of the green compact may be reduced. May exhibit slightly different behavior. In such a case, the GENT equation may be corrected as described below.

That is, as described above, the GENT equation is a viscosity conversion equation that is satisfied when the object to be measured can be assumed to be an incompressible fluid. On the other hand, in a green compact formed by press-molding an inorganic powder and a vehicle, a volume change accompanying the volatilization of a binder or the like may occur as the firing proceeds.

In order to correct this volume change, first, a volume obtained by multiplying the apparent volume of the green compact by the filling rate of the inorganic powder in the green compact is defined as a sample volume correction value V ′. '
Can be applied to the GENT equation. The filling rate of the inorganic powder can be easily calculated from the true specific gravity of the inorganic powder, the mixing ratio, and the weight of the compact.

For example, as shown in the flowchart of FIG. 2, the weight m _{1 of the} inorganic powder, the true specific gravity n ₁ , the sample weight m of the green compact, the amount w ₁ of the inorganic powder, and the amount w _{2 of the} vehicle component Is measured, and the sample volume correction value V ′ is calculated according to the following equation.
Can be calculated. V ′ = m1 / n1, m1 = m × ｛w1 / (w1 + w
2)｝

In the temperature region where the sintering shrinkage is dominant in the displacement of the green compact, it is desirable to consider the sample deformation speed accompanying the sintering shrinkage. That is, as shown in FIG. 3, the apparent sample deformation rate of the green compact includes the sample deformation rate due to plastic deformation and the sample deformation rate due to sintering shrinkage. , The sample deformation speed that compensated for it, ie, the sample deformation speed correction value (dh
/ Dt) ′ is desirably applied to the GENT equation.

Here, as shown in FIG. 3, in the temperature region X where sintering shrinkage is dominant, the sample deformation rate (d
h / dt) ₀ can be regarded as the sample deformation rate accompanying sintering shrinkage. Therefore, in order to derive the sample deformation speed in the temperature region X, the sample deformation speed (dh / dt) ₀ at zero load may be calculated.

This sample deformation rate at zero load (dh / d
t)₀Are loads A, B,... As shown in FIG.
, The sample deformation speed (dh / d
t) _A, (Dh / dt)_B... and then it
The relationship between the load and the sample deformation rate at each temperature is close to a straight line
The value extrapolated to zero load is assumed to be similar
Sample deformation speed at zero (dh / dt)₀Calculated as
You.

[0034] Specifically, as shown in the flowchart of FIG. 4, the green compact, the load A when the temperature T ₁ of
Sample deformation rate at (dh / dt) _A, to measure the sample deformation rate (dh / dt) _B at load B. By executing the linear fit according to the least square method using the sample deformation rate (dh / dt) _A at load A, the sample deformation rate (dh / dt) _B at load B, when the temperatures T ₁ Calculate the sample deformation speed (dh / dt) ₀ at zero load.

Similarly, the sample deformation speed (dh / dt) ₀ at zero load at the temperatures T ₂ , T _3, ...
As shown in FIG. 5, a sample deformation speed-temperature curve ((dh / dt) ₀ -T curve) at zero load is prepared. A sample deformation speed-temperature curve under load A and a sample deformation speed-temperature curve under load B were prepared. From these curves, a sample deformation speed-temperature curve at zero load ((dh / dt) ₀ -T Curve) can be calculated at once.

Next, as shown in the flow chart of FIG. 4, a sample deformation speed correction value (dh / dt) ′ to be applied to the temperature region X where sintering shrinkage is dominant is calculated. The sample deformation speed correction value (dh / dt) 'can be calculated by taking the difference between the apparent sample deformation speed and the sample deformation speed accompanying sintering shrinkage.

Specifically, it is the apparent sample deformation speed.
Sample deformation rate under load A (dh / dt)_AOr load
Sample deformation speed at B (dh / dt)_BFrom sintering shrinkage
The sample deformation rate at zero load, which is the sample deformation rate (d
h / dt)₀Is subtracted from the sample deformation speed correction value (d
h / dt) '. This operation is performed at the temperature T
₁, T_Two, T_Three…, Deformation of the sample at each temperature
The speed correction value (dh / dt) 'is calculated.

Further, as shown in the flowchart of FIG. 4, a temperature region X in which sintering shrinkage is dominant and a temperature region Y in which plastic deformation is dominant are separated. This separation is caused by the sample deformation rate-temperature curve ((dh /
dt) ₀ -T curve).

Specifically, as shown in FIG. 5, the minimum value in the sample deformation speed-temperature curve ((dh / dt) ₀ -T curve) at zero load is regarded as its boundary temperature Tb, A temperature region lower than Tb is defined as a temperature region X in which sintering shrinkage is dominant, and a temperature region higher than the boundary temperature Tb is defined as a temperature region Y in which plastic deformation is dominant.

As shown in FIG. 6, with respect to the displacement of the green compact, in the temperature region X where sintering shrinkage is dominant, G
Regarding the ENT equation, sample volume V → sample volume correction value V ′ sample deformation speed dh / dt → sample deformation speed correction value (dh /
dt) ′, while plastic deformation is dominant in the temperature region Y
Then, correction of the sample volume V → the sample volume correction value V ′ is performed for the GENT equation.

According to the present invention, such a series of GENT
By the formula correction, the viscosity of the green compact after calcination can be measured with higher accuracy. The temperature of amorphous glass powder, crystallized glass powder, glass ceramic composite powder, etc. A viscosity curve can be created with higher accuracy.

That is, in the method for measuring the viscosity of a green compact according to the present invention, (A) the sample volume correction value V ′ of the green compact after calcination (provided that the sample volume correction value V ′ (B) a sample deformation speed correction value (dh / dt) 'of the green compact after calcination (where the sample deformation speed correction value (dh /
dt) ′ is the step of obtaining the difference between the apparent sample deformation rate and the sample deformation rate due to sintering shrinkage), and (C) the temperature at which sintering shrinkage is dominant for the displacement of the green compact after calcination. (D) For the temperature region X where the sintering shrinkage is dominant, the sample volume correction value V ′ is defined as the sample volume V of the GENT equation. Applying the sample deformation speed correction value (dh / dt) ′ as the sample deformation speed dh / dt, and (E) the GENT-type sample for the temperature region Y where the plastic deformation is dominant. Applying the sample volume correction value V ′ as the volume V.

Further, as the apparent sample deformation speed,
Calculated sample deformation rate of a load _A (dh / dt) A, sample deformation rate of a load B a (dh / dt) _B respectively (where,
Load A ≠ Load B), Sample deformation speed at the load A (dh
/ Dt) _A , the sample deformation rate under the load B (dh / d
t) A linear approximation of _B is performed, and an extrapolated value at zero load is determined as a sample deformation speed at zero load (dh / dt) ₀ , and the sample deformation speed at zero load (dh / dt) ₀ is calculated by the sintering. Considering the sample deformation speed due to shrinkage, from the sample deformation speed (dh / dt) _A at the load _A or the sample deformation speed (dh / dt) _B at the load B, the sample deformation speed at the zero load The value obtained by subtracting (dh / dt) ₀ can be used as the sample deformation speed correction value (dh / dt) ′.

However, from the sample deformation rate at three or more different loads (eg, load A, load B and load C: where load A 荷重 load B ≠ load C), the sample deformation rate at zero load (dh) / Dt) It is desirable to obtain ₀ by linear approximation. The sample deformation rate at zero load (dh / d
This is because t) ₀ can be extracted more accurately.

In this case, in particular, the load A and the load B
Is the load A <load B, and the difference between the sample deformation speed (dh / dt) _B at load _B and the sample deformation speed (dh / dt) ₀ at zero load is the sample deformation speed correction value. (D
h / dt) ′. If the apparent sample deformation speed at the time of calculating the sample deformation speed correction value (dh / dt) ′ is the sample deformation speed when the load is small, the variation in extracting the sample deformation speed correction value tends to increase. There is.

Further, in the present invention, a sample deformation speed at zero load-temperature curve is prepared according to the sample deformation speed at zero load (dh / dt) ₀ , and a minimum value thereof is defined as a boundary temperature Tb. The temperature range X where the sintering shrinkage is dominant on the side lower than the temperature Tb can be set as the temperature range Y where the plastic deformation is dominant on the side higher than the boundary temperature Tb.

However, the method of extracting the boundary temperature is not limited to the above method. For example, a sample deformation speed-temperature curve for a bulk sample is prepared, and the sample deformation speed-temperature curve at zero load is obtained. The temperature region following the sample deformation speed-temperature curve of the bulk sample can be regarded as a temperature region Y in which plastic deformation is dominant.

[0048]

The present invention will be described below with reference to specific examples.

First, amorphous glass powders represented by Sample 1, Sample 2 and Sample 3 were produced by a high-temperature melting method.
Table 1 below shows the composition systems, thermal characteristics, powder characteristics, and the like of the amorphous glass powders of Sample 1, Sample 2, and Sample 3.

[0050]

[Table 1]

Next, an aqueous vehicle (vinyl acetate) was added to each of the amorphous glass powders of Samples 1, 2 and 3.
They were mixed and dispersed using a ball mill. Then, the obtained mixture was press-molded using a metal mold (φ7 mm) to produce a columnar compact having a height of 8 to 8.5 mm and a diameter of 7 to 7.5 mm.

Then, with respect to the green compact formed of each of the amorphous glass powders of Samples 1 to 3, the green compact was calcined in the vicinity of the softening point by using an electric furnace, and the diameter and the high The length was measured with a micrometer. The calcining was performed using a program in which the temperature was raised from room temperature to the calcining temperature at a rate of 3 ° C./min, kept at the calcining temperature for one hour, and allowed to cool to room temperature.

For comparison, a bulk sample was prepared using amorphous glass powder of each composition shown in Table 1.
For these bulk samples, each amorphous glass powder was poured into a platinum crucible, melted and gradually cooled from a slow cooling temperature to room temperature, and then polished with a polishing device to obtain bulk parallelism. The obtained sample was 6 mm high,
It is a cylindrical bulk sample having a diameter of 7 mm.

Next, with respect to the green compacts of Sample 1, Sample 2, and Sample 3, the sample displacement was measured using a parallel plate pressure viscometer (manufactured by Opto Corporation) having the structure shown in FIG. According to the procedure described above, a viscosity-temperature curve was determined. In addition,
A load of 138.8 g was applied to each sample, and the rate of temperature rise at the time of sample displacement measurement using a parallel plate pressure viscometer was 5 ° C./min. Similarly, a viscosity-temperature curve of the bulk sample was determined.

The calcination temperature was as follows: (1) softening point plus 50 ° C. (2) softening point plus 30 ° C. (3) softening point Plus 20 ° C (4) softening point plus 10 ° C (5) softening point (6) softening point minus 10 ° C (7) softening point minus 20 ° C (8) softening point minus 30 ° C (9) softening point minus 50 ° C 9 Performed under conditions. In addition, the measurement was also performed when not calcined as a monitor.

As a result, in any of the green compacts of Sample 1, Sample 2, and Sample 3, when the calcination temperature is higher than the softening point (1) to (4), the sample may be deformed. Was. That is, when calcined at a temperature higher than the softening point of the amorphous glass powder, the glass powder in the green compact becomes soft and flows, and the sample form of the green compact cannot be maintained. there were. From this, it is desired that the calcination temperature is lower than the softening point.

When the green compact of Sample 1 was calcined at its softening point, ie, 450 ° C. (5),
As shown in FIG. 7, it can be seen that the viscosity-temperature curve “•” when calcined approaches the viscosity curve “□” by the bulk method. It seems that at the softening point, that is, at 450 ° C., the necking between the powder particles is sufficient in the green compact, so that its viscous behavior is very close to that of the incompressible fluid. When it was calcined at a softening point minus 10 ° C. (440 ° C.) (6), FIG.
As shown in the figure, it can be seen that the viscosity-temperature curve “●” when calcined in the same manner as above approaches the viscosity curve “□” by the bulk method. It seems that even at the softening point minus 10 ° C., that is, 440 ° C., the necking between the powder particles is sufficient in the green compact, so that its viscous behavior is very close to that of the incompressible fluid. The standard of the viscosity in this method is a temperature at the same viscosity, and the difference from the bulk is within 2%.

On the other hand, when the green compact of Sample 1 was calcined at a softening point of minus 20 ° C. (430 ° C.) (7),
When calcined at a softening point of minus 30 ° C. (420 ° C.) (8), and when calcined at a softening point of minus 50 ° C. (400 ° C.) (9), as shown in FIG. 9, FIG. It can be seen that the viscosity-temperature curve “●” when calcined departs from the viscosity curve “□” by the bulk method and approaches the viscosity curve “△” when not calcined. This is presumably because at a temperature lower than the softening point minus 10 ° C., that is, at a temperature lower than 440 ° C., the green compact was not calcined sufficiently and the necking between the powder particles was incomplete.

When the green compact of Sample 2 was calcined at the softening point, ie, 430 ° C. (5),
As shown in FIG. 12, it can be seen that the viscosity-temperature curve “●” when calcined approaches the viscosity curve “□” by the bulk method. This seems to indicate that at the softening point, ie, 430 ° C., in the green compact, the necking between the powder particles is sufficient, so that its viscous behavior is very close to that of the incompressible fluid. When calcined at a softening point minus 10 ° C (420 ° C) (6), FIG.
As shown in FIG. 3, it can be seen that the viscosity-temperature curve “•” when calcined in the same manner as described above approaches the viscosity curve “□” by the bulk method. This is the softening point minus 10 ° C,
That is, even at 420 ° C., the necking between the powder particles is sufficient in the green compact, so that its viscous behavior seems to be very close to that of the incompressible fluid. The standard of the viscosity in this method is a temperature at the same viscosity, and the difference from the bulk is within 2%.

On the other hand, when the green compact of Sample 2 was calcined at a softening point of minus 20 ° C. (410 ° C.) (7),
When calcined at a softening point minus 30 ° C. (400 ° C.) (8) and when calcined at a softening point minus 50 ° C. (380 ° C.) (9), as shown in FIGS. It can be seen that the viscosity-temperature curve “●” when calcined is different from the viscosity curve “□” according to the bulk method and approaches the viscosity curve “△” when not calcined. this is,
As described above, at a temperature lower than the softening point minus 10 ° C., that is, lower than 420 ° C., it is considered that the green compact was not sufficiently calcined, and necking between powder particles was incomplete.

On the other hand, in the green compact of Sample 3, when it was calcined at the softening point, ie, 560 ° C. (5),
As shown in FIG. 17, it can be seen that the viscosity-temperature curve “●” when calcined approaches the viscosity curve “□” by the bulk method. This seems to indicate that at the softening point, ie, 560 ° C., in the green compact, the necking between the powder particles is sufficient, so that its viscous behavior is very close to that of the incompressible fluid. When calcined at a softening point minus 10 ° C (550 ° C) (6), FIG.
As shown in FIG. 8, it can be seen that the viscosity-temperature curve “●” when calcined in the same manner as described above approaches the viscosity curve “□” by the bulk method. This is the softening point minus 10 ° C,
That is, even at 550 ° C., since the necking between the powder particles is sufficient in the green compact, its viscous behavior seems to be very close to that of the incompressible fluid. Further, even when it is calcined at a softening point of minus 20 ° C. (540 ° C.) (7), and when it is calcined at a softening point of minus 30 ° C. (530 ° C.) (8), FIGS. As shown, it can be seen that the viscosity-temperature curve “温度” when calcined in the same manner as described above approaches the viscosity curve “□” by the bulk method. This is the softening point minus 20 ° C,
That is, 420 ° C or softening point minus 30 ° C, that is, 4
Even at 10 ° C, the viscous behavior seems to be very close to that of the incompressible fluid due to sufficient necking between the powder particles in the green compact. The standard of the viscosity in this method is a temperature at the same viscosity, and a difference from the bulk is within 2%.

However, when the green compact of Sample 3 was calcined at the softening point minus 50 ° C. (510 ° C.) (9), FIG.
As shown in FIG. 1, the viscosity-temperature curve “●” when calcined
Was separated from the viscosity curve “□” obtained by the bulk method, and approached the viscosity curve “△” when not calcined. This is because, as described above, at a temperature lower than the softening point minus 30 ° C., that is, at a temperature lower than 530 ° C., the green compact was not calcined sufficiently, and necking between powder particles was incomplete. Seem.

From the above, the calcination temperature is not higher than the softening point (softening temperature) of the amorphous glass powder. Further, in order to generally apply the calcination conditions, the softening point is minus one.
It is understood that the temperature is preferably from 0 ° C. to the softening point.

That is, the powder compact is calcined at an appropriate temperature in advance, whereby the powder particles are sufficiently necked, and the inorganic powder, particularly the amorphous glass powder, is pressed. Regarding the viscosity, the viscosity behavior of the green compact can be evaluated and measured with high accuracy in a medium viscosity region of 10 ⁴ to 10 ⁹ Pa · S, which is extremely important in the sintering process and the like.

[0065]

According to the method for measuring the viscosity of a green compact of the present invention, a green compact formed by press-molding an inorganic powder such as an amorphous glass powder is calcined in advance, and the particles are sufficiently necked. By doing so, the viscosity of a compact having a viscous behavior very close to the powder state can be measured with extremely high accuracy.

[Brief description of the drawings]

FIG. 1 shows a method for measuring the viscosity of a green compact according to the present invention.
It is a schematic flowchart figure which shows one Embodiment.

FIG. 2 is a flowchart illustrating a step of extracting a sample volume correction value according to the present invention.

FIG. 3 is a sample deformation speed-temperature curve for conceptually explaining the sample deformation speed correction in the present invention.

FIG. 4 is a flowchart illustrating a step of extracting a sample deformation speed correction value and a step of determining a boundary temperature between a temperature region where sintering shrinkage is dominant and a temperature region where plastic deformation is dominant in the present invention. It is.

FIG. 5 is a sample deformation speed-temperature curve for explaining the determination of a boundary temperature between a temperature region where sintering shrinkage is dominant and a temperature region where plastic deformation is dominant in the present invention.

FIG. 6 is a flowchart for explaining a method of applying a sample volume correction value and a sample deformation speed correction value to the GENT equation in the present invention.

FIG. 7 is a viscosity-temperature curve when the green compact of Sample 1 is calcined at its softening temperature in this example.

FIG. 8 is a viscosity-temperature curve when the green compact of Sample 1 is calcined at a softening temperature minus 10 ° C.

FIG. 9 is a viscosity-temperature curve when the green compact of Sample 1 is calcined at its softening temperature minus 20 ° C.

FIG. 10 is a viscosity-temperature curve when the green compact of Sample 1 is calcined at its softening temperature minus 30 ° C.

FIG. 11 is a viscosity-temperature curve when the green compact of Sample 1 was calcined at a softening temperature minus 50 ° C.

FIG. 12 is a viscosity-temperature curve when the green compact of Sample 2 is calcined at its softening temperature.

FIG. 13 is a viscosity-temperature curve when the green compact of Sample 2 is calcined at a softening temperature minus 10 ° C.

FIG. 14 is a viscosity-temperature curve when the green compact of Sample 2 is calcined at a softening temperature thereof minus 20 ° C.

FIG. 15 shows a viscosity-temperature curve when the green compact of Sample 2 was calcined at a softening temperature thereof minus 30 ° C.

FIG. 16 is a viscosity-temperature curve when the green compact of Sample 2 was calcined at a softening temperature minus 50 ° C.

FIG. 17 shows a viscosity-temperature curve when the green compact of Sample 3 was calcined at the softening temperature.

FIG. 18 shows a viscosity-temperature curve when the green compact of Sample 3 was calcined at a softening temperature of −10 ° C.

FIG. 19 is a viscosity-temperature curve when the green compact of Sample 3 is calcined at a softening temperature of −20 ° C.

FIG. 20 is a viscosity-temperature curve when the green compact of Sample 3 was calcined at a softening temperature thereof minus 30 ° C.

FIG. 21 is a viscosity-temperature curve when the green compact of Sample 3 was calcined at a softening temperature minus 50 ° C.

FIG. 22 is a schematic sectional view of a parallel plate pressure viscometer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Measurement object 2a, 2b ... Quartz plate 3 ... Support base 4 ... Quartz rod 5 ... Heater 6 ... Device

──────────────────────────────────────────────────続 き Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 11/00-11/16 G01N 3/00 JICST file (JOIS)

Claims (5)

(57) [Claims] 1. The viscosity η of a green compact obtained by press-molding an inorganic powder is determined by the GENT formula: η = 2πMGH ⁵ / 3V (dh / dt) (2πH ³ + V) (where M: load, H: Sample height, G: gravitational acceleration,
(V: sample volume, dh / dt: sample deformation rate) in a method for measuring the viscosity of a green compact, wherein a pre-calcined green compact is used for the measurement. Viscosity measurement method. 2. The method according to claim 1, wherein the inorganic powder is one kind of oxide inorganic powder selected from the group consisting of amorphous glass powder, crystallized glass powder, and glass-ceramic composite powder. 2. The method for measuring the viscosity of a green compact according to 1. 3. The method for measuring the viscosity of a green compact according to claim 1, wherein the calcining is performed at a temperature lower than a softening temperature of the inorganic powder. 4. A softening temperature T (° C.) of the inorganic powder,
The method for measuring the viscosity of a green compact according to claim 3, wherein the calcination is performed at a temperature of T-10 ° C or higher. 5. A sample height H of the calcined green compact,
Measuring the sample volume V, measuring the sample deformation speed dh / dt of the green compact when a load M is applied by a parallel plate pressure viscometer, and measuring the sample calculated in each of the steps. Applying the height H, the sample volume V, and the sample deformation rate dh / dt to the GENT equation to calculate the viscosity η of the green compact. The method for measuring the viscosity of a green compact according to any one of the above.