Preparation method of zirconium diboride ceramic with in-situ-introduced boron as additive

Abstract

The invention relates to the field of structural ceramic manufacturing, in particular to a preparation method of zirconium diboride ceramic with in-situ-introduced boron as an additive. The preparation method comprises the following steps: firstly, performing ball milling and mixing zirconium dioxide and elemental boron in a mol ratio of (1: 3.5)-(1: 4.5), and drying to obtain ZrO2 / B mixed powder; secondly, putting the ZrO2 / B mixed powder into a graphite crucible, and performing high-heat treatment at the air pressure of below 200Pa to obtain ZrB2 / B powder; and finally, sieving the obtained ZrB2 / B powder, performing isostatic pressing, putting the ZrB2 / B powder into the graphite crucible, performing pressureless sintering in an argon atmosphere, controlling the sintering temperature at 1800 -2100 DEG C, the heat-preserving time at 1-3 hours and the heating rate at 10-50 DEG C / min, and preserving heat for 0.5 hours at 1500-1700 DEG C to obtain the compact zirconium diboride ceramic. By the preparation method, a ball milling medium is not introduced, the impurity content is reduced, excellent performance of the zirconium diboride ceramic can be maintained easily, and the sintering compactness of the zirconium diboride ceramic is realized at a relatively low temperature (2000 DEG C).

Description

technical field [0001] The invention belongs to the field of non-oxide structure ceramics, and in particular relates to a preparation method of zirconium diboride ceramics in which boron is introduced in situ as an additive. Specifically, by introducing elemental boron in situ as an additive, pressureless sintering is used to obtain dense zirconium diboride single-phase ceramics at a relatively low temperature, and the relative density of the material is greater than 97%. Background technique [0002] Transition metal borides have excellent properties such as high melting point, hardness, thermal stability and corrosion resistance, and are widely used in the production of ultra-high temperature structural materials, and have important applications in mechanical processing, metallurgy and minerals, aerospace and other fields. Among many borides, ZrB 2 With its excellent mechanical properties, relatively low density, high melting point and good thermal conductivity, it has be...

AI Technical Summary

Problems solved by technology

Currently, ZrB 2 The synthesis method mainly contains following several: 1) direct synthesis method: take metal Zr simple substance and boron as raw material, directly synthesize in inert gas or vacuum high-temperature reaction, the synthetic powder purity of this method is high, and synthesis condition is relatively simple, but raw material Expensive, synthetic ZrB 2 Coarse powder particle size and low activity are not conducive to powder sintering and post-processing

2) Self-propagating combustion synthesis method: This synthesis process uses the reactant ZrO 2 , Mg and B 2 o 3 The huge heat released by the solid-state reaction of etc. maintains the spontaneous continuous progress of the reaction, so that the reactant is transformed into MB 2 ; This method is simple in process, fast in speed, short in time, extremely small in energy consumption, high in activity of the synthesized powder, and beneficial to sintering and post-processing; , product structure and performance are not easy to control is also its shortcoming

But so far, have not seen in ZrB 2 A report on elemental boron species added to ceramics

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