JP2892229B2 - Molded body for thermal history detection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is for detecting a thermal history in a ceramic firing step and the like, and in particular, a firing step for low-temperature fired ceramics and electronic material ceramics, a glaze baking step, and a thick film metallizing step. The present invention also relates to a heat history detecting molded body in firing or heat treatment in a low temperature range of 550 to 1200 ° C. in an oxidizing atmosphere in a heat treatment step of a metal material or the like.

[0002]

2. Description of the Related Art In a firing process for ceramics and the like,
The heat history received by the object to be fired changes depending on the temperature profile, the type of firing furnace, the settings in the furnace, and the like. That is, even if the firing temperature is the same, if other conditions are different, the thermal history will be different, and it is necessary to correctly detect the thermal history. For example, the thermal history of a body to be fired is detected using a Zegel cone disclosed in Japanese Utility Model Application Laid-Open No. 56-29441. What is Zegelcorn?
A plurality of triangular pyramids with different melting temperatures are provided on a support base, and after firing this Zegel cone together with the object to be fired, the thermal history is detected by the manner in which each triangular pyramid falls. Had become. However, since accurate detection is not possible with this, it is rarely used at present.

Therefore, as shown in, for example, Japanese Patent Application Laid-Open No. 1-184388, this molded body is fired together with a fired body using an unfired ceramic body,
It has been practiced to detect a thermal history by measuring a dimensional change due to shrinkage.

For example, a ring-shaped molding 20 as shown in FIG. 2 or a sheet-shaped molding 3 as shown in FIG.
0 was used.

When such a dimensional change due to firing shrinkage is measured, the dimensional change is conveniently converted to a temperature. However, this temperature is not a measurement of the actual temperature, but a thermal history. Therefore, in the present invention, it is referred to as an indicated temperature.

[0006]

However, the ceramic molded body for detecting thermal history described above is made of Al ₂ O ₃ or Si.
Since it was a crude material containing O ₂ , MgO or the like as a main component and containing a large amount of impurities, the firing shrinkage ratio varied, and the accuracy of the detected indicated temperature was poor.

Further, the ring-shaped one shown in FIG. 2 has a large area, so that a large space is required in the firing furnace.
The sheet-shaped one shown in FIG. 3 has a problem that warpage occurs and dimensions cannot be measured correctly.

[0008] Further, the ring-shaped thing is about 1100
It was measured only at about 1000 ° C. or higher in a sheet-like material at a temperature of 1000 ° C. or higher, and could not be used at 1000 ° C. or lower. Some of the above-mentioned Zegel cones are used even at 1000 ° C. or lower, but the detection accuracy is poor. That is, with the conventional heat history detecting molded body, it was impossible to accurately detect the heat history of 1000 ° C. or less.

[0009]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a ceramic powder of 5 to 90% by weight, such as alumina, which forms an aggregate.
And a green compact of a mixture consisting of 10 to 95% by weight of glass powder as a binder was used as a thermal history detecting compact.

[0010] According to the present invention, by controlling the composition, the crushed particle size, and the density of the molded body, the variation in the accuracy of the indicated temperature can be made ± 2 ° C. In addition,
In the present invention, the reason why the glass powder is set to 10 to 95% by weight or more is that if the content is less than 10% by weight, almost no firing shrinkage occurs at 1200 ° C.
If the content is more than 5% by weight, warpage or deformation is likely to occur.

Further, in the present invention, in order to detect the thermal history at a lower temperature, it is preferable that the range is 5 to 70% by weight of the ceramic powder and 30 to 95% by weight of the glass powder.

Further, the average particle size of the molded article of the present invention is 1
0 μm or less, preferably 5 μm or less is good. By using such a raw material powder having a small particle diameter, variation in firing shrinkage can be reduced.

[0013]

Embodiments of the present invention will be described below.

As shown in FIGS. 1 (a) and 1 (b), a heat history detecting molded body 10 of the present invention has a chord portion 12 parallel to a disc body.
12 are formed, and the remaining arc portions are measurement surfaces 11 and 11 having excellent roundness. In addition, a concave portion 13 for distinguishing front and back is formed on one side, and a chamfer 14 is formed on corners of upper and lower surfaces. The concave portion 13 may have a simple concave shape, but may be engraved with a symbol or the like indicating a use temperature range.

The compact 10 is a green compact formed by press-forming a mixture of 5 to 90% by weight of ceramic powder and 10 to 95% by weight of glass powder.

Here, as the ceramic powder, alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), mullite (3Al ₂ O ₃ .2SiO ₂ ), steatite (M
gO.SiO ₂ ), oxide ceramics such as spodumene, forsterite (2MgO.SiO ₂ ), silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC),
A non-oxide ceramic such as aluminum nitride (AlN) may be used. The non-oxide ceramic itself has poor wettability with glass, but by forming an oxide film on the surface thereof, the wettability can be improved and a mixed molded article with glass can be obtained.

On the other hand, any kind of glass powder can be used. That is, as glass powder,
PbO, Ba, including various silicate glasses
Special glass or crystallized glass including O, ZnO, Li ₂ O, Na ₂ O, K ₂ O and other special powders can be used. Which glass powder is to be used is arbitrarily selected depending on the shrinkage characteristics of the molded article mixed with the oxide ceramic powder.

For example, Table 1 shows an example of the glass powder used in the present invention.

[0019]

[Table 1]

Then, as will be described later, the firing temperature of the molded body 10 is measured by changing the firing temperature under certain conditions, and the relationship between the dimensions and the firing temperature is prepared as a conversion table. Thereafter, when firing is performed under different conditions, the molded body 10 is fired together with the object to be fired, and the dimensions after firing are measured, whereby the indicated temperature can be obtained from the above conversion table.

As described above, the indicated temperature is not an actual temperature but a heat history for convenience. That is, by using the heat history detecting molded body of the present invention, even when firing conditions are different, it is possible to manage the heat history itself by obtaining the indicated temperature.

Further, the molded body 10 of the present invention comprises a chord portion 12,
Since it has 12, the area is smaller than that of the conventional example shown in FIG. 2, and a large space is not required in the firing furnace. Note that the chords 12 and 12 need not be parallel to each other, and may be formed only at one location. Further, since the molded body 10 of the present invention is a press-molded article having a certain thickness, no warping or the like occurs, and at the time of dimension measurement, an arc is formed as shown in FIG. Measurement surface 1
Measurements 1 and 11 may be measured with a constant pressure micrometer, and the same diameter D can be accurately measured even if the measurement position is shifted.

EXPERIMENTAL EXAMPLE 1 A ceramic powder composed of an alumina raw material having a purity of 99.9% or more and purified as an aggregate was mixed with a glass powder having a composition shown in Table 2 as a binder, and wet-pulverized with an alumina ball. A particle size analysis is performed by a laser light scattering method to obtain an average particle size of 2.0 ± 0.1 μm. An 8% by weight wax binder is added to the raw material powder, mixed, and spray-dried to obtain granules having good fluidity. The granules are placed in an air-conditioned molding chamber as shown in FIG.
Press molding to the shape shown in (b), at this time, the green density of the molded body is set in the range of 1.6 to 2.2 ± 0.005 g / cm ³ , and the molded body for heat history detection of the present invention is formed. Obtained.

Table 3 shows the relationship between the composition of the molded product and the shrinkage characteristics. As a result, the combination of alumina and glass A, and alumina and glass B,
It can be seen that the molded article can be used as a heat history detecting molded article in the low temperature range. In addition, ceramic powder is 10%
And a small No. Deformation was slightly observed during firing in the composition of No. 1, but deformation can be prevented by using crystallized glass as the glass powder. However, if the amount of the ceramic powder was less than 5% by weight, deformation such as warpage was likely to occur. On the other hand, the ceramic powder containing as much as 90% by weight of ceramic powder No. 1 Since the composition of No. 10 did not shrink at 1200 ° C., if the content of the ceramic powder was more than 90% by weight, the thermal history detection in the low temperature range, which is the object of the present invention, cannot be performed. Therefore, the ceramic powder is 5 to 90% by weight, and the glass powder is 10 to 95% by weight.
Those in the range were good.

[0025]

[Table 2]

[0026]

[Table 3]

EXPERIMENTAL EXAMPLE 2 In the case of 70% by weight of alumina and 30% by weight of glass A in Table 3 above, a heat history detecting molded body 10 having a diameter of 22.300 mm was produced in the same manner as in Example 1. Prepared. The molded body 10 was fired in a oxidizing atmosphere at a heating rate of 200 ° C./hour, a maximum firing temperature of 2 hours, and a cooling rate of 300 ° C./hour in a strictly controlled and calibrated firing furnace. For 1 hour. The dimensions of the molded body 10 after firing were measured at 20 ° C. with a constant pressure micrometer.

By varying the firing temperature (indicated temperature) in various ways, firing of 20 molded bodies 10 was repeated three times. The results are as shown in Table 4 and FIG. Also, the dimensional variation (3σ) at each temperature,
From the dimensional change per 1 ° C (tangent slope) at that temperature, the indicated temperature detection accuracy = ± (dimension variation) / (the dimensional change per 1 ° C), the indicated temperature detection accuracy (3σ) Was calculated. As a result, as shown in Table 4, within the range of 650 to 850 ° C., the detection accuracy of the indicated temperature could be kept within ± 2 ° C. Further, Table 4 shows the dimensions of the compact at each indicated temperature of 50 ° C. By measuring the dimensions at each indicated temperature more finely, a conversion table of the dimensions of the compact and the designated temperature is obtained. be able to.

[0029]

[Table 4]

In the above embodiment, only the ceramic powder using alumina is shown. In addition, oxide ceramics such as zirconia and mullite and non-oxide ceramics such as silicon nitride and silicon carbide are used. The results were almost the same.

[0031]

As described above, according to the present invention, a green body for detecting thermal history is constituted by a green body of a mixture of 5 to 90% by weight of ceramic powder and 10 to 95% by weight of glass powder. At a low temperature of about 550 to 1200 ° C., since the detection accuracy of the indicated temperature can be extremely high as ± 2 ° C. or less, the firing process can be strictly controlled even if the firing conditions are changed, and an excellent sintered body can be obtained. It is possible to obtain.

[Brief description of the drawings]

FIG. 1A is a plan view showing a heat history detecting molded body of the present invention, and FIG. 1B is a cross-sectional view taken along line XX in FIG.

FIG. 2 is a perspective view showing a conventional heat history detecting molded body.

FIG. 3 is a perspective view showing a conventional heat history detecting molded body.

FIG. 4 is a graph showing the relationship between the indicated temperature and the firing shrinkage in the molded article for detecting heat history of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Heat history detection molded body 11 ... Measurement surface 12 ... String part 13 ... Depression 14 ... Chamfer

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01K 11/06 G01K 11/00 C04B 35/63

Claims (1)

(57) [Claims] 1. A ceramic powder, such as alumina, zirconia, mullite, silicon carbide, silicon nitride, in an amount of 5 to 90% by weight;
A molded article for thermal history detection, comprising a green compact of a mixture of 10 to 95% by weight of glass powder as a binder.