Preparation method for promoting to sinter zirconium boride or zirconium carbide ceramics by using reaction aids

A reaction aid, zirconium boride technology, applied in the field of non-oxide composite ceramics to achieve uniform microstructure, low price and excellent performance

Active Publication Date: 2011-09-21
江苏先进无机材料研究院
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, taking advantage of the high sintering activity of the powders generated in situ during the reaction sintering process, the use of composite sintering aids that can react during the sintering process to achieve densification of zirconium boride and zirconium carbide ceramics has not been reported yet.

Method used

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  • Preparation method for promoting to sinter zirconium boride or zirconium carbide ceramics by using reaction aids
  • Preparation method for promoting to sinter zirconium boride or zirconium carbide ceramics by using reaction aids
  • Preparation method for promoting to sinter zirconium boride or zirconium carbide ceramics by using reaction aids

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] ZrB 2 (5~20μm, >90%) powder as raw material, Zr powder (5~15μm, 98%) and B 4 C powder (≤2μm, 99%) is a sintering aid, and the design reaction aids Zr and B 4 The amount of C added is 10wt%, and 4.16g zirconium powder and 0.84g B 4 C powder was added into a plastic tank, and ethanol was added to ultrasonically disperse for 15 minutes, and Si 3 N 4 After mixing the balls as the medium for 12 hours, add 45g of ZrB 2 , mixed for 12h, then removed ethanol with a rotary evaporator, dried and sieved to obtain ZrB containing reactive sintering aids 2 Powder. Put the uniformly mixed powder in a graphite mold coated with BN on the inner wall surface, and carry out reaction sintering in vacuum. The heating rate during sintering is 10-20°C / min. After the temperature rises to 1450°C, keep it at 1450°C for 30 minutes. After the heat preservation is over, apply a pressure of 20-30 MPa, then raise the temperature to a sintering temperature of 2000°C, and hold heat and pressure fo...

Embodiment 2

[0030] Design ZrB 2 Medium Zr and B 4 The amount of C added is 20wt%, among them, ZrB 2 Powder 40g, Zr powder 8.32g, B 4 C powder 1.68g. Ceramics were prepared according to the method of Example 1, the sintering temperature was 1900° C., and the heat preservation and pressure holding were carried out for 1 hour. The relative density of the material reaches 98.5%. After the mechanical performance test, the hardness of the material is 17GPa, and the toughness: 5.5MPa m 1 / 2 , Bending strength: 650MPa.

Embodiment 3

[0032] ZrB 2 Powder (5-20μm, >90%) is used as raw material, Zr powder (5-15μm, 98%) and C powder (≤2μm, 99%) are used as sintering aids, ZrB powder is designed 2 The addition amount of Zr and C is 10wt%. Add 4.42g of Zr powder and 0.58g of C powder into a plastic tank, add ethanol and ultrasonically disperse for 15min, then mix Si on a roll mixer 3 N 4 After mixing the ball for 12 hours, add 45g ZrB 2 , mixed for 12h, then removed ethanol with a rotary evaporator, dried and sieved to obtain ZrB containing reactive sintering aids 2Powder. Ceramics were prepared according to the method of Example 1, the sintering temperature was 2000° C., and the heat preservation and pressure holding were carried out for 1 hour. The relative density of the material reaches 98%. After the mechanical performance test, the hardness of the material is 18GPa, and the toughness is 5.0MPa m 1 / 2 , Bending strength: 630MPa.

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Abstract

The invention provides a preparation method for promoting to sinter zirconium boride or zirconium carbide ceramics by using reaction aids. Two-phase sintering aids capable of being reacted, namely Zr powder and C powder, or Zr powder and B4C powder, are added, and a material is promoted to be compact and crystals of a matrix are inhibited from growing by zirconium carbide/zirconium boride second phase particles with higher sintering activity, which are generated through in-situ reaction between the sintering aids. The ZrB2 or ZrC-based bulk material prepared by the method has the relative density of over 97 percent, the room temperature bending strength of 500-800MPa, the fracture toughness of 3.5-6.5MPa.ml/2, and the hardness of 14-20GPa. The second phase generated through the in-situ reaction has the same melting point as the matrix, and the sintering acids cannot bring adverse effect to the high temperature mechanical properties of the material.

Description

technical field [0001] The invention relates to a preparation method for promoting sintering of zirconium boride or zirconium carbide ceramics by using a reaction aid, belonging to the field of non-oxide composite ceramics. Background technique [0002] The strong covalent bonds of transition metal borides and carbide ceramics endow them with high melting points and low self-diffusion coefficients. Generally, relative density ceramic sintered bodies can only be obtained under high temperature (>2000°C) and high pressure (>30MPa). Although adding a small amount of Ni, Fe and other metal sintering aids or S 3 N 4 、MoSi 2 Non-metallic sintering aids such as non-metallic sintering aids improve their sintering properties by generating liquid phases. However, the residual low-melting point phases at the grain boundaries or trifurcation grain boundaries of ceramics will adversely affect the high-temperature mechanical properties and corrosion resistance of ceramics. Theref...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/58C04B35/56C04B35/622
Inventor 张国军王新刚阚艳梅王佩玲郭伟明
Owner 江苏先进无机材料研究院
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