Effect of AlN and ZrO2 on the microstructure and property of the 2Si-B-3C-N ceramic
Effect of AlN and ZrO2 on the microstructure and property of the 2Si-B-3C-N ceramic
复制标题
AlN和ZrO2对2Si-B-3C-N陶瓷微观结构和性能的影响
DOI：
10.1016/j.ceramint.2017.11.134
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发表时间：
2018
影响因子：
5.2
通讯作者：
Jia Dechang
中科院分区：
文献类型：
--
作者：
Zhang Pengfei;Yang Bin;Lu Zhi;Jia Dechang
机械合金化的非晶态2Si-B-3C-N粉末在1900℃的Ar气氛中热压30分钟。在2Si-B-3C-N陶瓷中加入少量AlN和ZrO2(5%)，研究了它们对2Si-B-3C-N陶瓷的烧结工艺、显微组织和性能的影响。X射线衍射仪、扫描电子显微镜、透射电子显微镜和性能测试结果表明，AlN或ZrO2的加入促进了2Si-B-3C-N复合粉末的烧结过程，促进了2Si-B-3C-N复合粉末的晶化和晶粒长大，提高了陶瓷的密度和力学性能。在80℃的轴向压力和8℃的气压下，不添加任何添加剂的2Si-B-3C-N陶瓷在高于1830℃时才发生显著的致密化。AlN和ZrO2的加入使这一临界温度分别降低到1760℃和1730℃左右。结果表明，制备的块体陶瓷的平均晶粒度从80 nm增加到200 nm和250 nm，相对密度从88.7%提高到96.9%和97.7%，抗弯强度从331 Mpa提高到416 Mpa和575 Mpa。仔细研究发现，在所制备的块体陶瓷中，AlN与碳化硅形成固溶体，而ZrO2以t-ZrO2和m-ZrO2纳米晶的形式存在。因此，AlN和ZrO2的加入可能以困难的方式促进2Si-B-3C-N陶瓷的原子扩散、晶粒长大和致密化过程。
The mechanically-alloyed amorphous 2Si-B-3C-N powder was hot pressed at 1900 °C for 30 mins in argon. A small amount (5 mol.%) of AlN and ZrO2was added to investigate their effect on the sintering process, microstructure and properties of the 2Si-B-3C-N ceramic. XRD, SEM, TEM and property testing results show that, the addition of AlN or ZrO2promotes the sintering process of the 2Si-B-3C-N composite powder, accelerates the crystallization and grain growth, and improves the density and mechanical properties of the prepared ceramic. Under an axial pressure of 80 MPa and a gas pressure of 8 bar, significant densification occurs to the 2Si-B-3C-N ceramic free from any additives just when the temperature is higher than 1830 °C. The addition of AlN and ZrO2decreases this critical temperature to about 1760 °C and 1730 °C, respectively. As a result, for the prepared bulk ceramic, the average grain size is increased from 80 nm to 200 nm and 250 nm, the relative density is enhanced from 88.7% to 96.9% and 97.7%, and the bending strength is improved from 331 MPa to 416 MPa and 575 MPa, respectively. Careful investigation reveals that in the prepared bulk ceramic, AlN forms solid solution with SiC, and ZrO2exists in the form of t-ZrO2and m-ZrO2nanocrystals. Thus, the addition of AlN and ZrO2may facilitate the atomic diffusion, the grain growth and the densification process of the 2Si-B-3C-N ceramic in difficult ways.