烧结助剂TiO_(2)添加量及烧结制度对Cr_(2)O_(3)烧结致密化行为的影响

Effect of TiO_(2) Sintering Assistant Addition and Sintering System on Sintering Densification Behavior of Chromium Oxide

以Cr_(2)O_(3)微粉为原料、TiO_(2)微粉为烧结助剂,在不同温度(1000~1500℃)、不同保护气体(氩气、氮气)中烧结制备Cr_(2)O_(3),研究了TiO_(2)添加量(0,1%,3%,5%,质量分数)、烧结温度和烧结气氛对Cr_(2)O_(3)烧结致密化行为的影响。结果表明:随着TiO_(2)添加量增加,试样线收缩率和相对密度增加,致密化程度提高,当TiO_(2)添加量为5%时,线收缩率和相对密度最大,分别为16.25%,92.51%,添加TiO2后形成的(Cr_(0.88)Ti_(0.12))_(2)O_(3)置换固溶体可以提升扩散传质速率,从而促进烧结致密;随着烧结温度升高,Cr_(2)O_(3)的烧结致密化程度先升高后降低,1300°C下烧结最致密,氮气中烧结后在Cr_(2)O_(3)颗粒表面形成Cr_(2)N膜层,可以发挥类似液相作用,提高烧结速率,制备的Cr_(2)O_(3)相比在氩气中更致密。

Cr_(2)O_(3) material was prepared under different temperatures(1 000-1 500℃) and different protective atmospheres(argon,nitrogen) by using Cr_(2)O_(3) powder as raw material and TiO_(2) powder as sintering assistant.The effect of TiO_(2) addition(0,1%,3%,5%,5%,mass fraction),sintering temperature and sintering atmosphere on sintering densification behavior of Cr_(2)O_(3) was analyzed.The results show that with the increase of TiO_(2) addition,the linear shrinkage rate and relative density of the sample increased,and the densification degree increased.When the TiO_(3addition) was 5%,the linear shrinkage rate and relative density reached the maximum,which were 16.25% and 92.51 %,respectively.After adding TiO_(2),(Cr_(0.88)Ti_(0.12))_(2)O_(3) replacement solid solution was formed to improve the diffusion mass transfer rate and promote sintering densification.With the increase of sintering temperature,the sintering densification degree of Cr_(2)O_(3) first increased and then decreased,and reached the maximum at 1 300 ℃.After sintering in nitrogen atmosphere,the Cr_(2N) film was formed on the surface of Cr_(2)O_(3) particles after sintering in nitrogen,which could play a similar role to the liquid phase and improve the sintering speed,the Cr_(2)O_(3) prepared was denser than that prepared in argon atmosphere.