Molded body for thermal history detection

Abstract

This molded body for thermal history detection contains an oxide powder and an organic binder. The oxide powder contains 91 mass% or more of an alumina powder. In the molded body for thermal history detection, the percentage of the number of oxide powder particles having a particle diameter of 1 μm to less than 10 μm is 91% or greater.

Description

Molded body for detecting thermal history

[0001] The present disclosure relates to a molded article for detecting thermal history.

[0002] 2. Description of the Related Art Conventionally, as disclosed in Patent Document 1, a ceramic molded body for detecting thermal history is known, which detects thermal history by measuring the dimensions of a ceramic molded body that has shrunk due to heat treatment.

[0003] Japanese Patent Application Publication No. 4-65369

[0004] A thermal history detection molded body according to one aspect of the present invention contains an oxide powder and an organic binder. The oxide powder contains 91 mass% or more of alumina powder. In the thermal history detection molded body, the number ratio of the oxide powder particles having a particle size of 1 μm or more and less than 10 μm is 91% or more.

[0005] Fig. 1 is a plan view showing an example of a molded body for detecting thermal history according to an embodiment. Fig. 2 is a cross-sectional view taken along line A-A shown in Fig. 1. Fig. 3 is a graph showing the particle size distribution of the oxide powder in sample No. 1.

[0006] The above-mentioned molded body for thermal history detection is handled in an incompletely sintered state after shrinkage due to heat treatment, and therefore is prone to defects such as chipping of the measuring surface, so there is room for improvement in terms of improving strength. Note that, hereinafter, the molded body after shrinkage due to heat treatment will be referred to as the "treated molded body."

[0007] Therefore, it is desired to provide a molded article for detecting thermal history that can provide a molded article having excellent strength after treatment.

[0008] Hereinafter, embodiments of the molded product for detecting thermal history disclosed in the present application will be described in detail. Note that this disclosure is not limited to the embodiments shown below. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of each element may differ from reality. Furthermore, there may be parts in which the dimensional relationships and ratios differ between the drawings.

[0009] Furthermore, in the following embodiments, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "perpendicular," or "parallel" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

[0010] Fig. 1 is a plan view showing an example of a molded article for detecting thermal history according to an embodiment, and Fig. 2 is a cross-sectional view taken along line AA shown in Fig. 1.

[0011] The thermal history detection molded body 10 of the present disclosure has a first surface 12a, a second surface 12b located on the opposite side of the first surface 12a, and a third surface 13 located between the first surface 12a and the second surface 12b.

[0012] 1, the first surface 12a and the second surface 12b are arc-shaped surfaces that include a part of an imaginary circle 11 whose center is a point P. The third surface 13 includes a surface 13a and a surface 13b that are positioned parallel to each other.

[0013] The first surface 12a and the second surface 12b are a pair of detection surfaces 12 for detecting thermal history. For example, by sandwiching the upper surface 14 and the lower surface 15 of the thermal history detection molded body 10 and removing it from the firing furnace without touching the detection surfaces 12, the thermal history of the thermal history detection molded body 10 in the firing environment can be detected.

[0014] The thermal history detection molded body 10 of the present disclosure contains an oxide powder and an organic binder. The thermal history detection molded body 10 may contain impurities other than the oxide and the organic binder.

[0015] The oxide powder contains 91 mass % or more of alumina powder. This makes it easier to obtain a molded product for thermal history detection having mechanical strength suitable for the intended use. The oxide powder may or may not contain oxides other than alumina.

[0016] The organic binder contributes to the shape retention of the thermal history detection molded body 10 according to this embodiment. The organic binder is used, for example, in the granulation process of the oxide powder. The material of the organic binder may be, for example, paraffin, acrylic resin, or the like.

[0017] Furthermore, in the thermal history detection molded body 10 of the present disclosure, the proportion of oxide powder particles having a particle size of 1 μm or more and less than 10 μm is 91% or more, which makes it easier to obtain a processed molded body having strength suitable for the intended use.

[0018] Furthermore, the thermal history detection molded body 10 of the present disclosure may have a number ratio of oxide powder having a particle size of 10 μm or more of less than 4%, or even less than 3%. The thermal history detection molded body 10 according to this embodiment, in which the number ratio of oxide powder having a particle size of 10 μm or more is less than 4%, has fewer starting points that will damage the shape of the treated molded body compared to the thermal history detection molded body 10 in which the number ratio is 4% or more, and therefore can improve the strength of the treated molded body.

[0019] Furthermore, the thermal history detection molded body 10 of the present disclosure may have a number ratio of oxide powder having a particle size of less than 1 μm of less than 5%. The thermal history detection molded body 10 according to this embodiment, in which the number ratio of oxide powder having a particle size of less than 1 μm is less than 5%, is expected to have more uniform thermal shrinkage than the thermal history detection molded body 10 in which the number ratio of oxide powder is 5% or more. Therefore, the thermal history detection molded body 10 according to this embodiment improves the accuracy of detecting the thermal history of the molded body after treatment.

[0020] The thermal history detection molded body 10 of the present disclosure may have a maximum oxide powder diameter of less than 16 μm. The thermal history detection molded body 10 according to this embodiment, in which the maximum oxide powder diameter is less than 16 μm, has fewer starting points that will damage the shape of the molded body after treatment, compared to the thermal history detection molded body 10 in which the maximum oxide powder diameter is 16 μm or more. Therefore, the thermal history detection molded body 10 according to this embodiment can improve the strength of the molded body after treatment.

[0021] The thermal history detection molded body 10 of the present disclosure has an oxide powder specific surface area of ​​1.7 m2 measured by the BET method. ２ ・g －１As a result, even in the case of an unsintered green compact 10 for thermal history detection, the specific surface area of ​​the oxide powder may be 1.7 m or less. ２ ・g －１ The strength of the molded article after treatment can be made higher than that when the temperature is above 1000 K.

[0022] The oxide powder contained in the thermal history detection molded body 10 of the present disclosure contains 99 mass % or more of Al ２ O ３ With such a composition, for example, problems such as contamination of the object to be fired in a firing furnace together with the molded body for detecting thermal history according to this embodiment are unlikely to occur, and the molded body for detecting thermal history 10 can be made highly versatile.

[0023] The particle size of the oxide powder contained in the thermal history detection molded body 10 of the present disclosure is a circle-equivalent diameter calculated based on the cross-sectional shape of the oxide powder measured using a laser diffraction method. Specifically, the following processes (a) to (d) were performed in this order, and then the measurement was performed.

[0024] (a) Granules composed of oxide powder and an organic binder were heated in air at 460°C for 6 hours to remove the organic binder. (b) Oxide powder (0.4 g) was added to water (350 mL) and a 5% by mass aqueous solution of sodium hexametaphosphate (2 mL) was added to prepare an oxide powder dispersion. (c) The oxide powder dispersion was stirred for 2 minutes using an ultrasonic homogenizer. (d) The particle size distribution of the oxide powder in the oxide powder dispersion was measured using a laser diffraction / scattering particle size distribution analyzer MT3300 manufactured by Microtrac-Bell Corporation. The measurement was performed once, the measurement time was 30 seconds, the particle transmittance was transparent, the particle refractive index was 2.2, the particle shape was aspherical, and the solvent refractive index was 1.333. The target concentration index (DV) value was 0.055.

[0025] In addition, the content of alumina powder in the oxide powder and Al ２ O ３ The content of can be quantified using an X-ray fluorescence analyzer (XRF). Specifically, the following processes (a) to (c) were carried out in this order to quantify the content.

[0026] (a) Granules consisting of oxide powder and organic binder were heated in air at 460°C for 6 hours to remove the organic binder. (b) The oxide powder was packed into an aluminum ring with a diameter of 30 mm and a thickness of 4 mm, and pressure-molded to a thickness of 1 mm to prepare a sample. (c) A semi-quantitative analysis (FP method) was performed using a Rigaku Corporation ZSX100e X-ray fluorescence analyzer to determine the Al content relative to the total mass of the sample prepared in (b) above. ２ O ３ The X-rays used here are Rh-Ka rays generated from an Rh tube.

[0027] Furthermore, the strength of the thermal history detection molded article 10 of the present disclosure after heat treatment at 1667°C for 2 hours can be compared, for example, based on three-point bending strength. Specifically, the three-point bending strength was measured in accordance with JIS R 1601-1995 using a Shimadzu Corporation tensile compression tester (autograph) AG-5kNIS MS. The strength was measured by processing the above-mentioned processed molded article to have a cross section of 3 mm x 4 mm. Note that strength tests were not performed on commercially available products from other companies because their shape could not be processed into test pieces.

[0028] Next, an example of a method for manufacturing the thermal history detection molded article 10 of the present disclosure will be described. The thermal history detection molded article 10 of the present disclosure can be used to detect thermal history at, for example, 1400°C to 1700°C.

[0029] The specific surface area of ​​the oxide powder was measured by the BET method.

[0030] [Samples No. 1 to 5] Water and a dispersant were added to the alumina powder, which was the main component, in a predetermined ratio, and mixed. Grinding media were added, and the mixture was ground in a mill until the specified particle size was reached. The particle size distribution was controlled by changing the type and amount of grinding media, the rotation speed of the mill, etc.

[0031] The particle size distribution of the alumina powder used in Samples No. 1 to 5 was measured. Specifically, the proportions of particle sizes less than 1 μm, 1 μm or more and less than 10 μm, 10 μm or more and less than 100 μm, and 100 μm or more in the obtained alumina powder, as well as the maximum particle size, were measured, and the results are shown in Table 1.

[0032] The obtained alumina powder was used to prepare a slurry, and an organic binder was added to the obtained slurry, mixed, and spray-dried to obtain granules whose main component was alumina. The obtained granules were molded into a predetermined shape to prepare molded bodies for thermal history detection, Samples No. 1 to 5.

[0033] [Sample No. 6] As Sample No. 6, which is a comparative example, a competitor's product (Measuring) used as a molded article for detecting thermal history was used.

[0034] Granules composed of the oxide powder and the organic binder were heated at 460°C for 6 hours to remove the organic binder. The specific surface area of ​​the oxide powder was measured by the BET method. Specifically, the specific surface area was measured by the BET single-point method using a flow system in accordance with JIS R 1626-1996 using a Macsorb HM model-1210 manufactured by Mountech Co., Ltd., and the results are shown in Table 2.

[0035] The bulk density and relative density of the treated compacts were measured by the Archimedes method in accordance with JIS R 1634-1998. The results are shown in Table 2.

[0036] Furthermore, the three-point bending strength of the obtained molded article for thermal history detection was measured. Specifically, the three-point bending strength was measured in accordance with JIS R 1601-1995 using a tension and compression testing machine (autograph) AG-5kNIS MS manufactured by Shimadzu Corporation. The results are shown in Table 2.

[0037]

[0038]

[0039] Figure 3 is a graph showing the particle size distribution of the oxide powder in Sample No. 1. As shown in Table 1, Sample No. 1 had a number ratio of oxide powder particles having a particle size of 1 μm or more and less than 10 μm of 92.97%. Sample No. 1 also had a number ratio of oxide powder particles having a particle size of 10 μm or more of 2.15%. Sample No. 1 also had a number ratio of oxide powder particles having a particle size less than 1 μm of 4.88%. Sample No. 1 also had a maximum oxide powder diameter of 15.56 μm.

[0040] Furthermore, as shown in Table 2, the three-point bending strength of Sample No. 1 was greater than the three-point bending strength of Samples Nos. 2 to 5, and a molded article for thermal history detection was obtained that had high strength after treatment.

[0041] The present disclosure has been described in detail above, but the present disclosure is not limited to the above-described embodiments, and various modifications, improvements, etc. are possible within the scope that does not deviate from the gist of the present disclosure.

[0042] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

[0043] 10 Molded body for detecting thermal history 12 Detection surface 12a First surface 12b Second surface 13 Third surface

Claims

1. A molded body for detecting thermal history, comprising an oxide powder and an organic binder, wherein the oxide powder contains 91 mass% or more of alumina powder, and the proportion of the oxide powder particles having a particle size of 1 μm or more but less than 10 μm is 91% or more.

2. The thermal history detection molded body according to claim 1, wherein the proportion of the oxide powder particles having a particle size of 10 μm or more is less than 4%.

3. A molded body for detecting thermal history according to claim 1 or 2, wherein the proportion of the oxide powder particles having a particle size of less than 1 μm is less than 5%.

4. The thermal history detection molded body according to any one of claims 1 to 3, wherein the maximum diameter of the oxide powder is less than 16 μm.

5. The specific surface area of the oxide powder measured by the BET method is 1.7 m ２ ・g －１ The molded article for detecting thermal history according to any one of claims 1 to 4, wherein:

6. The oxide powder contains 99% by mass or more of Al ２ O ３ The thermal history detection molded article according to any one of claims 1 to 5, comprising:

7. A molded body for detecting thermal history according to any one of claims 1 to 6, having a first surface, a second surface located opposite the first surface, and a third surface located between the first surface and the second surface, wherein the first surface and the second surface form a pair of detection surfaces for detecting thermal history.

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