Method for coating h-BN coating on surface of porous Si3N4 substrate

A substrate and coating technology, applied in the field of coating h-BN coating on the surface of porous Si3N4 substrate, can solve the problems of complex process and high price, and achieve the effect of good quality and low cost

Inactive Publication Date: 2010-09-01
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

High-quality h-BN coatings are mostly prepared by vapor deposition methods, including chemical vapor deposition (CVD), metal-organic chemical vapor deposition (MOCVD), low-pressure chemical vapor deposition (LPCVD), and ion-assisted vapor deposition. method (team CVD), laser-assisted vapor deposition (LACVD), etc., but the disadvantages of these methods are that they are expensive and the process is complicated

Method used

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  • Method for coating h-BN coating on surface of porous Si3N4 substrate
  • Method for coating h-BN coating on surface of porous Si3N4 substrate
  • Method for coating h-BN coating on surface of porous Si3N4 substrate

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Effect test

Embodiment 1

[0018] This embodiment includes the following steps:

[0019] 1. By mass ratio, 30% Si 3 N 4 , 5% of Y 2 o 3 , 5% Al 2 o 3 Mix it with 60% petroleum coke and put it into a ball milling tank, use absolute ethanol as the ball milling medium, and ball mill it with silicon nitride balls for 24 hours to obtain a slurry;

[0020] 2. Dry the prepared slurry in a 40°C drying oven for 12 hours, pass through a 200-mesh sieve to obtain a powder, press the obtained powder into a green disc, and 2 Sintered at 1600°C for 2h in the atmosphere, N 2 The pressure is 3 atmospheres to obtain Si with a porosity of 35% 3 N 4 matrix;

[0021] 3. The sintered Si 3 N 4 The surface of the substrate was cleaned with absolute ethanol, and then dried in a drying oven at 40°C for later use, and then commercial H 3 BO 3 Uniform overcoating on Si 3 N 4 Substrate surface, required H 3 BO 3 Quality and Si 3 N 4 The surface area ratio of the matrix is ​​0.2g / cm 2 ;

[0022] Four, will be co...

Embodiment 2

[0025] This embodiment includes the following steps:

[0026] 1. Mix 50% Si by mass ratio 3 N 4 , 4% Y 2 o 3 , 6% Al 2 o 3 Mix it with 40% petroleum coke and put it into a ball milling tank, use absolute ethanol as the ball milling medium, and use silicon nitride balls to mill for 48 hours to obtain a slurry;

[0027] 2. Dry the prepared slurry in a drying oven at 60°C for 6 hours, pass through a 200-mesh sieve to obtain a powder, press the obtained powder into a green disc, and 2 Sintered at 1800°C for 2.8h in the atmosphere, N 2 The pressure is 2 atmospheres to obtain Si with a porosity of 25% 3 N 4 matrix;

[0028] 3. The sintered Si 3 N 4 The surface of the substrate was cleaned with absolute ethanol, and then dried in a drying oven at 60°C for later use, and then commercial H 3 BO 3 Uniform overcoating on Si 3 N 4 Substrate surface, required H 3 BO 3 Quality and Si 3 N 4 The surface area ratio of the matrix is ​​0.3g / cm 2 ;

[0029] Four, will be coat...

Embodiment 3

[0032] This embodiment includes the following steps:

[0033] One, 41% Si by mass ratio 3 N 4 , 5% of Y 2 o 3 , 4%Al 2 o 3 Mix it with 50% petroleum coke and put it into a ball milling tank, use absolute ethanol as the ball milling medium, and ball mill it with silicon nitride balls for 24 hours to obtain a slurry;

[0034] 2. Dry the prepared slurry in a drying oven at 50°C for 9 hours, pass through a 200-mesh sieve to obtain a powder, and press the obtained powder into a green disc. 2 Sintered at 1650°C for 3h in the atmosphere, N 2 The pressure is 2 atmospheres to obtain Si with a porosity of 28% 3 N 4 matrix;

[0035] 3. The sintered Si 3 N 4 The surface of the substrate was cleaned with absolute ethanol, and then dried in a drying oven at 50°C for later use, and then commercial H 3 BO 3 Uniform overcoating on Si 3 N 4 Substrate surface, required H 3 BO 3 Quality and Si 3 N 4 The surface area ratio of the matrix is ​​0.6g / cm 2 ;

[0036] Four, will be ...

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Abstract

The invention discloses a method for coating an h-BN coating on the surface of a porous Si3N4 substrate, which comprises the following steps of: 1, mixing Si3N4, Y2O3, Al2O3 and refinery coke in a mass ratio and grinding the mixture to prepare slurry; 2, drying and screening the slurry, pressing obtained powder into green compact and sintering the green compact in an N2 atmosphere to obtain the Si3N4 substrate; 3, washing and drying the Si3N4 substrate and coating H3BO3 onto the surface of the Si3N4 substrate; 4, heating the Si3N4 substrate coated with the H3BO3 and obtaining uniform B2O3 on the surface of the Si3N4 substrate; and 5, heating the Si3N4 substrate of which the surface has the B2O3 obtained in the step 4, and performing carbothermic reduction reaction to obtain the h-BN coating coated on the surface of the Si3N4 substrate. The method has the characteristics of low cost and simple operation; and a complex prepared structure integrates the advantages of two ceramic materials and can be widely applied to metal forming moulds.

Description

technical field [0001] The present invention relates to the method for porous substrate coating, particularly a kind of porous Si 3 N 4 A method for coating h-BN coating on the surface of substrate. Background technique [0002] Porous Si 3 N 4 As a structural material used at high temperatures, ceramics have the advantages of excellent thermal stability, corrosion resistance, oxidation resistance and high mechanical strength, showing great potential and advantages in engineering applications. h-BN has high thermal conductivity, stable chemical properties, chemical inertness to almost all molten metals, strong oxidation resistance, high thermal stability, strong neutron absorption capacity and good electrical insulation. Therefore, it has potential high application value in ceramics, refractory, electrical, catalysis and other fields. The h-BN ceramic material has the advantages of high thermal conductivity, excellent electrical insulation performance, extremely low the...

Claims

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Application Information

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IPC IPC(8): C04B35/584C04B35/622C04B41/87
Inventor 杨建锋白宇于方丽梁森乔冠军张国军
Owner XI AN JIAOTONG UNIV
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