Two-step sintering method of diamond-B4C-SiC three-phase composite ceramic

A composite ceramic and sintering method technology, which is applied in the field of three-phase composite ceramics to achieve the effect of promoting low temperature densification, improving mechanical properties and good bonding

Active Publication Date: 2022-04-12
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the present invention, when the sintering temperature reaches T1 (1550°C-1600°C), it will drop to T2 (1500°C-1550°C) at a constant speed. Instead of the traditional heat preservation stage, it effectively prevents diamond graphitization, solves the problem of diamond graphitization at a temperature lower than the densification of boron carbide, and effectively suppresses the residue of SiO2 in the sample , which promotes the densification of the sample and improves the mechanical properties of the sample

Method used

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  • Two-step sintering method of diamond-B4C-SiC three-phase composite ceramic
  • Two-step sintering method of diamond-B4C-SiC three-phase composite ceramic
  • Two-step sintering method of diamond-B4C-SiC three-phase composite ceramic

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Experimental program
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Effect test

Embodiment 1

[0030] Embodiment 1 (comparative example)

[0031] A Diamond-B 4 The preparation method of C-SiC three-phase composite ceramics comprises the following steps:

[0032] (1) Take by weight 40% diamond powder, 30% Si powder, 30% B powder respectively by mass percentage, the diamond powder particle size is 40 μ m, the B powder particle size is 1 μ m, the Si powder particle size is 1 μ m, and the grinding ball is SiC, The ball-to-material ratio is 5, dispersed with anhydrous ethanol, ball milled for 6 hours and then dried by a rotary evaporator. After drying, the mixed powder (that is, diamond-Si-B ternary mixed powder) is dried in a vacuum oven for 24 hours.

[0033] (2) Disperse the diamond-Si-B ternary mixed powder through a 100-mesh sieve to prevent hard agglomeration of the powder, and weigh the powder into In the graphite mold, the inner wall of the graphite mold, the indenter and the powder are separated by graphite paper, and the graphite mold is wrapped with graphite fe...

Embodiment 2

[0038] A Diamond-B 4 The two-step sintering method of C-SiC three-phase composite ceramics comprises the following steps:

[0039] (1) Take by weight 40% diamond powder, 30% Si powder, 30% B powder respectively by mass percentage, the diamond powder particle size is 40 μ m, the B powder particle size is 1 μ m, the Si powder particle size is 1 μ m, and the grinding ball is SiC, The ball-to-material ratio is 5, dispersed with anhydrous ethanol, ball milled for 6 hours and then dried by a rotary evaporator. After drying, the mixed powder (that is, diamond-Si-B ternary mixed powder) is dried in a vacuum oven for 24 hours.

[0040] (2) Disperse the diamond-Si-B three-phase mixed powder through a 100-mesh sieve to prevent hard agglomeration of the powder, and weigh the powder into In the graphite mold, the inner wall of the graphite mold, the indenter and the powder are separated by graphite paper, and the graphite mold is wrapped with graphite felt.

[0041] (3) Put the graphite...

Embodiment 3

[0044] A Diamond-B 4 The two-step sintering method of C-SiC three-phase composite ceramics comprises the following steps:

[0045] (1) Take by weighing 55% diamond powder, 30% Si powder, 15% B powder respectively by mass percentage, the diamond powder particle size is 25 μ m, the B powder particle size is 3 μ m, the Si powder particle size is 3 μ m, and the grinding ball is SiC, The ball-to-material ratio is 4, dispersed with absolute ethanol, ball-milled for 12 hours, and then dried by a rotary evaporator. After drying, the mixed powder (that is, diamond-Si-B ternary mixed powder) is placed in a vacuum drying oven for 12 hours.

[0046] (2) Disperse the diamond-Si-B ternary mixed powder through a 100-mesh sieve to prevent hard agglomeration of the powder, and weigh the powder into In the graphite mold, the inner wall of the graphite mold, the indenter and the powder are separated by graphite paper, and the graphite mold is wrapped with graphite felt.

[0047] (3) Put the g...

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Abstract

The invention relates to a two-step sintering method of diamond-B4C-SiC three-phase composite ceramic, which comprises the following steps: taking a mixture of diamond powder, Si powder and B powder as a raw material, carrying out spark plasma sintering in situ by adopting a two-step method, and heating to the highest temperature T1 at the rate of 100-200 DEG C / min at the front stage of sintering; then, the highest temperature is reduced to T2 through the cooling process of 5-15 min, and therefore the diamond-B4C-SiC three-phase composite ceramic is obtained; wherein T1 ranges from 1550 DEG C to 1600 DEG C, T2 ranges from 1500 DEG C to 1550 DEG C, and the difference value between T1 and T2 is not smaller than 40 DEG C. According to the method, a traditional heat preservation stage is replaced by a stage of reducing the temperature to 1500-1550 DEG C at a constant speed, so that diamond graphitization is effectively prevented, the problem of diamond graphitization is solved at the temperature lower than the densification temperature of boron carbide, SiO2 residues in a sample are effectively inhibited, densification of the sample is promoted, the mechanical property is improved, and the method is suitable for industrial production. The obtained three-phase composite ceramic is compact in structure, good in interface bonding and free of graphite residues, and has the characteristics of light weight, superhardness, high strength and high toughness.

Description

technical field [0001] The present invention relates to three-phase composite ceramics, more specifically, relates to a kind of diamond-B 4 A two-step sintering method for C-SiC three-phase composite ceramics. Background technique [0002] B 4 C due to its high hardness (the third hard substance) and low density (2.52g / cm 3 ), is an excellent engineering structural material. In order to solve its poor sintering ability (> 2000 ℃), low fracture toughness (2 ~ 3MPa m 1 / 2 ) and other shortcomings, sintering at low temperature to obtain dense B with high toughness 4 C bulk materials have received extensive attention, mainly in B 4 The introduction of the second phase into the C matrix can effectively reduce the sintering temperature or improve the fracture toughness, but this will reduce the B 4 C inherent light weight and high hardness characteristics. [0003] Diamond is the hardest engineering material and can be used as a reinforcing phase to improve B 4 The perfo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/528C04B35/573C04B35/577C04B35/563C04B35/645
Inventor 王为民唐荣解晶晶何强龙邹冀
Owner WUHAN UNIV OF TECH
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