JPS6183675A - Manufacture of low expansion substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing a low expansion substrate.

(Technical background of the invention and its problems) As a conventional ceramic substrate with a small coefficient of thermal expansion,
A cordierite substrate is used as the base of the sheet heating element. In this case, the cordierite letterpress uses cordierite composition: V, chamotte as the raw material, so the thermal expansion coefficient is 21 x 1o "/"C, which is a low expansion, but when manufacturing the board, The firing temperature of 1, 2
The drawback is that it reaches a high temperature of 0.000 to 1.500° C., and its bending strength is as high as 1) 6 kg/d.

Another low expansion substrate is glass ceramics.
This has a thermal expansion coefficient of 8 to 15 x 10-7,
! /'C, and the bending strength is 1. 5 (It is large, with 9 layers in 10, and is a very good low-expansion substrate. However, the disadvantages of this glass ceramic are that it is thick and heavy, and the manufacturing process is complicated, making it very expensive.) I can get two.

In addition, there was also a drawback that even if a paper-making method was used to make paper with cordierite-composed minerals and fibers, it would not be possible to agglomerate and make paper.

(Objective of the invention) The present invention eliminates the above-mentioned drawbacks and
The present invention provides a method for producing a low-expansion ceramic substrate that can be fired at a low temperature of 900°C, has a small coefficient of thermal expansion, and is manufactured at low cost.

(Summary of the invention) That is, the present invention provides a sheet material obtained by agglomerating and forming a slurry of clay, Akatsuki talc, and kaori into a slurry of 700 to 900
This is a method for manufacturing a low expansion substrate characterized by firing at a temperature of .degree.

(Detailed Description of the Invention) That is, in the present invention, the ceramic substrate is
The thermal expansion coefficient is 10 to 30 so that it can be fired at 900°C and to prevent the fired substrate from cracking due to thermal shock.
The raw materials are mixed to approximately X10 /C. The raw materials were mixed with clay, calcined melk, kaolin, and magnesium oxide so that the composition would be cordierite with a small coefficient of thermal expansion, and the ratio of alumina (A1203), silicon dioxide (SiO2), and magnesium 77ide (MgO) was 2Nigo.・Make it 2A1203・5S102.

To explain this point in more detail, commonly used ceramic raw materials, such as frog's eye clay, calcined talc, and kaolin, are not composed of pure AIyOs + SiO -120), alkali metal oxides (such as Na20.l(2(')), and alkaline earth oxides (CaO), as well as oxidized and (
It contains impurities such as Fe203, which can be converted using the chemical equation. These H2O, Na20, Fe
Impurities such as 2O3 have the harmful effect of increasing the coefficient of thermal expansion, but
On the other hand, even a small amount of it has the effect of lowering the sintering temperature. In the present invention, the weight ratio of these impurities is 3
A-120s +, which is the main component, is kept within the range of ~12 pieces.
The raw materials are mixed so that the blending ratio of b + O□, Δ・1go becomes cordierite.

By doing so, it is possible to perform sintering at a low sintering temperature, and at the same time obtain a ceramino substrate with a low coefficient of thermal expansion.

For reference, the three dimensions of commonly used ceramic raw materials are: Tetsuki, its main component At 2u, , 5in2. - indicates the weight percentage of sgo.

The remainder corresponds to the above-mentioned impurities.

According to the above table, in order to bring the main component closer to the cordierite composition, it is possible to appropriately determine the ratio of each raw material and separately add MgO, which tends to be insufficient.

Powders of these raw materials are aggregated together with fibers in water, and paper is made into sheets. This sheet is fired as it is, or after being made into various shapes if necessary, it is placed in an electric filter in an oxidizing atmosphere. Firing is performed at approximately 400 parts, held for 1 hour to burn out and vaporize the organic substance, and then fired at approximately 800 parts. In this way, a low expansion substrate is produced.

The present invention will be explained below based on specific examples. All compositions are weight ratios.

〈Example 1〉 (A+ Preparation of sample r Hara-meki-sando 1088 part 1
Takataru Ri
! 3 4@+(13),
Flocculant first, 1) Aluminum ball mill with raw clay 108
8 parts, Akatsuki talc 784 parts, kaolin 136 parts.

and 530 parts of magnesium oxide were added and pulverized for 8 hours.

Mix. After pulverization, the pulverized powder is added to a 21-sized container containing 1,000 parts of water and 162 parts of asbestos, and stirred for 2 minutes to form a hydraulic slurry.

Add 60 parts of sulfuric acid band prepared in advance to this water I raw slurry, stir it, and confirm that P tl is 3 to 4 on the P l-1 test 71' crosspiece, and then add it here. Add 120 parts of a polyacrylamide thread molecular flocculant previously prepared and stir for 50 seconds to flocculate. The agglomerated sample as described above is made into paper using a paper making machine to form a sheet of 300 mm square and 15 to 22 mm thick. This sheet-like material can be used as it is or folded into a shape that suits the purpose of use, and heated at 40°C at 2"C/min from room temperature.
Heating to 0°C to burn off and vaporize organic substances.
Hold at 400°C for 1 hour. Then, up to 800°C 4
The temperature was raised at 800° C./min and held at 800° C. for 1 hour to sinter the ceramic.

・1 unit ・After firing, let it cool in the Y to room temperature, and then open the door to the low expansion group. Remove the board from the electric y.

When we examine the coefficient of thermal expansion of the extracted material, it is "l"
3 X i Oi /C, bending strength 180kl;l
It is Δ.

Example 2> (, ~) FJ of trial pitch 1! A low expansion substrate was obtained by firing in the same manner as in Example 1 using the above-mentioned composition (A) and (l ()) as a coagulant (B). is i 5Xi O' 1./
'C, and the bending strength was 160 to 9/cyrE.

(Effects of the invention) The low expansion substrate thus obtained can be used as a heat-resistant substrate for household heat-resistant plates, barbecue single-layer, or in the medical, food, and chemical industrial fields. suitable for

According to the present invention, the ceramic substrate has the advantages of being thin, having good workability, being able to be molded into any shape, being lightweight, having strength, and being resistant to thermal shock.

In addition, compared to conventional methods, the process is simpler and the firing temperature is lower, so it is useful for energy saving and can be supplied at low cost.

Claims (1)

[Claims] (1) Ceramic raw materials such as clay, calcined talc, and kaolin and magnesium oxide powder are mixed to approximate the composition of cordierite, and fibers are mixed with this to form an aqueous slurry, which is then coagulated and made into paper. A method for manufacturing a low-expansion substrate, which comprises firing a sheet-like product at a temperature of 700 to 900°C.