JPH02228543A - Reference sample for verifying test and manufacture thereof - Google Patents

Abstract

PURPOSE:To enable application of a non-destructive inspection and a verifying test of a ceramic product ideally by providing a hole or a foreign matter which simulates a defect to control a size and a position thereof inside. CONSTITUTION:When a position of a defect is fixed, a primary molded product 1 with a shape desired to introduce the defect is divided in two or more at a location where the defect is desired to introduce to add a defect introducing material 3 at a specified position of a divided surface 2 thereof. It is necessary to set a primary molding pressure at the moment to a value lower than a main molding pressure in the subsequent process. Then, the molded product 1 divided in two or more is integrated; that with a simple shape is integrated with a mechanical press and that with a complicated shape is integrated with a hydrostatic press to obtain a molded product 4 to be baked. Then, when a sintering aid decomposes or the defect introducing material is an organic material, the organic material is decomposed by oxidation. Finally, a main baking of material is performed at an optimum temperature and atmosphere to simulate a defect. Thus, a sample can be obtained having a hole or a foreign matter with a size and position thereof controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a standard sample for guarantee testing suitable for use as a standard for non-destructive testing and guarantee testing of ceramic products, and a method for manufacturing the same.

(Prior Art) Ceramics are brittle materials, and if defects such as pores of several tens of microns or more, foreign matter, cracks, etc. are present inside the ceramics, they are likely to break due to the defects. Therefore, it is necessary to guarantee the quality of ceramic products by conducting non-destructive inspections and guarantee tests to detect defects.

X-ray flaw detection and ultrasonic flaw detection are well known as nondestructive testing methods for ceramic bodies, and thermal shock testing is well known as a guarantee test. In non-destructive testing using X-rays, ultrasonic waves, etc., it is necessary to know in advance the size of defects that can be detected by the equipment and to set optimal flaw detection conditions. For this reason, conventionally, ceramic bodies with holes of various sizes drilled with a drill or laser have been used as reference samples for defects. In addition, to set the test temperature for thermal shock tests, holes of various sizes were drilled into the ceramic body using a drill or laser, and the relationship between defect size and thermal shock temperature was investigated.

(Problem to be solved by the invention) However, the size of the defect processed by the above-mentioned drill or laser beam is at most 200 μmφ.
Since the pores can only be reduced to a certain extent and are open defects, their shape and size are completely different from the pores inherent in actual ceramic products, making accurate inspection and testing impossible.

For example, the defect echo height of a 200 μmφ drill hole detected by ultrasonic flaw detection is much larger than the echo height of a 200 μmφ hole inherent in a ceramic body, making it difficult to know the actual size of the defect. There were some problems, such as not being able to do it.

Therefore, in the above-mentioned non-destructive inspection and warranty test of ceramic products, a standard sample for warranty test is required that has a clear reference for the size and position of defects in order to conduct various tests. That is, in nondestructive testing, it was necessary to calibrate the device using a reference sample, and in warranty testing, it was necessary to use the reference sample as a standard for estimating the strength of the product.

However, pores, which are defects specific to ceramic materials,
Conventionally, there has been no standard sample that simulates foreign objects, cranks, etc., nor has a method for producing such a standard sample been established.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a standard sample for a guarantee test that can be suitably used in non-destructive inspections and guarantee tests of ceramic products, and a method for manufacturing the same.

(Means for Solving the Problems) The standard sample for guarantee testing of the present invention is a standard sample for use as a standard for non-destructive testing of ceramic bodies, and is used to simulate defects and determine their size and position. It is characterized by having controlled pores or foreign matter inside.

In addition, the method for manufacturing the reference sample for the guarantee test of the present invention is as follows:
This method is characterized in that the above-mentioned standard sample for guarantee is manufactured by obtaining pores by firing an organic substance or by arranging an oxide to obtain foreign substances.

(Function) In the above-mentioned configuration, since the reference sample for the guarantee test of the present invention has holes or foreign matter whose size and position are controlled, a plurality of reference samples with different sizes and positions are prepared. Using these reference samples, calibration of non-destructive testing equipment and guarantee testing of ceramic products can be suitably carried out.

In order to form pores or foreign matter at a predetermined position within the test piece, an organic material such as peach seeds or cruzi shells that can withstand molding pressure and burn out during calcination is crushed to a predetermined particle size is used to form pores. In order to form foreign matter, it is preferable to use oxides such as ZrO, FezO4*Crz03, etc. that have been ground to a predetermined particle size.

In other words, it is preferable to select a pore-forming organic substance that has a Young's modulus equivalent to that of a peach seed or a cruzi shell.Organic materials such as polyethylene and polystyrene have a low Young's modulus and are free from defects introduced during unloading of press pressure. Cracks occur around the material and defects larger than the predetermined particle size are generated, making it impossible to obtain an appropriate reference sample for guarantee testing.

(Example) FIG. 1 is a flowchart showing an example of producing a standard sample for a guarantee test of the present invention. First, the ceramic powder used as the base material and the defective material are crushed and the particle size is adjusted using a sieve. At this time, in order to cause pores to exist in the ceramic body, it is preferable to use an organic substance such as peach seeds as a defect material in order to take advantage of the effect of pore generation due to burning. In addition, in order to allow foreign substances to exist within the ceramic body,
ZrO□, Fc40. due to interface formation due to thermal expansion difference.
It is preferable to use oxides such as oxides such as

Further, as the ceramic powder serving as the base material, it is necessary to use the same raw material as the material to be inspected, such as silicon nitride, zirconia, alumina, and silicon carbide.

Next, the ceramic powder and the defect material whose particle size has been adjusted are mixed together with other sintering aids and then molded. In this molding, it is necessary to determine the size and position of the defects, etc., and the defect introduction material is prepared by following the flow shown in Figure 1 in advance, and the defect size in the fired body is confirmed. These controls are implemented based on the relationship with the defect size.

When introducing defects randomly as a control method, a predetermined random defect density is obtained by controlling the volume ratio of the sieved defect-introducing material of a predetermined particle size and the ceramic powder. Also, when determining the location of defects,
First, as shown in FIGS. 2(a) and 3(a), the primary molded body 1 having a shape in which a defect is to be introduced is divided into two or more parts at the desired location, and the defect is placed at a predetermined position on the dividing surface 2. Introduction material 3
Add. The subsequent molding pressure at this time needs to be lower than the main molding pressure in the next step. Next, the primary molded bodies divided into two or more parts are integrated, and those with a simple shape as shown in Figure 1(b) are pressed by a mechanical press, and those with a complex shape as shown in Figure 2(b) are pressed statically. The molded body 4 to be fired is obtained by integrating with a hydraulic press.

Next, the sintering aid is decomposed, and if the defect-introducing material is an organic substance, the organic substance is oxidized and decomposed before firing.

The heating temperature is 300'C with a heating rate of 50°C/hour or less.
The temperature is increased to a constant temperature of preferably 450°C or higher,
Calcination is carried out by holding at this temperature for 5 hours or more, preferably 24 hours or more. At this time, if the ceramic powder is silicon nitride or silicon carbide, it needs to be calcined at 800° C. or lower because it is easily oxidized.

Finally, main firing is performed at the optimum temperature and atmosphere for each material to simulate the defects of the present invention to obtain a standard sample for guarantee testing that has pores or foreign matter whose size and position are controlled.

The obtained reference test sample can be used for non-destructive testing using X-ray flaw detection or ultrasonic flaw detection, for example, by making multiple ceramic bodies with different defect sizes and measuring them. It is possible to determine the conditions, know the performance of the flaw detection equipment, and use the results as a reference for calibrating the equipment. In addition, in the guarantee test,
By creating standard samples for guarantee testing that have the same shape as the test object with controlled defects and measuring them using a prescribed test method, it is possible to guarantee the temperature of thermal shock tests and the strength of products using the materials. It becomes possible.

(Effects of the Invention) As is clear from the detailed explanation above, according to the standard sample for guarantee testing and the manufacturing method thereof of the present invention, it is possible to obtain a test piece in which pores and foreign matter in the ceramic body are controlled. Using this ceramic body as a reference, it becomes possible to calibrate non-destructive testing equipment for X-ray flaw detection or ultrasonic flaw detection, and to perform guarantee tests on ceramic products with high accuracy.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing an example of producing a standard sample for guarantee testing of the present invention; FIGS. 2(a), (b) and 3(a), (
b) is a diagram for explaining the method of controlling the defect position.

Claims (1)

[Scope of Claims] 1. A reference sample for use as a reference for non-destructive testing of ceramic bodies, etc., which has voids or foreign matter whose size and position are controlled to simulate defects inside. A standard sample for warranty testing featuring: 2. The method for producing a standard sample for a guarantee test according to claim 1, characterized in that voids simulating defects are formed by firing the organic substance. 3. The method for producing a reference sample for a guarantee test according to claim 1, characterized in that a foreign substance simulating a defect is formed by arranging an oxide.