Processing and characterization of SiB0.5C1.5N0.5 produced by mechanical alloying and subsequent spark plasma sintering
Processing and characterization of SiB0.5C1.5N0.5 produced by mechanical alloying and subsequent spark plasma sintering
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DOI：
10.1016/j.msea.2007.11.012
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发表时间：
2008-08
期刊：
影响因子：
6.4
通讯作者：
Zhihua Yang;D. Jia;Yu Zhou;Jiuxing Zhang
中科院分区：
文献类型：
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作者：
Zhihua Yang;D. Jia;Yu Zhou;Jiuxing Zhang
用机械合金化方法合成了SiB0.5C1.5N0.5纳米粉末，粉末中形成了以非晶相为主的少量纳米晶相。结果表明，碳化硅微晶为碳化硅，碳化硅的晶型为3C和6H。采用放电等离子烧结(SPS)技术，在1800℃、不同的烧结压力下对SiB0.5C1.5N0.5粉末进行了固结。在25 MPa下烧成的陶瓷，不能清晰地区分出碳化硅和氮化硼的晶界。当压力增加到40 Mpa时，碳化硅相几乎完全晶化，其晶粒度小于1μm，氮化硼主要分布在碳化硅晶界。在烧结陶瓷中发现了一些非晶态结构。随着烧结压力的增加，陶瓷的相对密度从76.6%增加到92.4%，力学性能提高2~3倍。在40 Mpa压力下烧成的陶瓷，其抗折强度、断裂韧性、弹性模数和维氏硬度分别达到311.5 Mpa、3.45MPam1/2、133.0 Gpa和3.68 Gpa。SiBCN陶瓷在空气中的质量在930℃以下损失了几个百分点，然后在1100℃以上保持不变。
SiB0.5C1.5N0.5nanopowders were synthesized by mechanical alloying method, and a predominantly amorphous with a small volume fraction of nanocrystalline phase was formed in the powders. The results showed that the crystallites were SiC, and the polytype of SiC were 3C and 6H. SiB0.5C1.5N0.5powders were consolidated by spark plasma sintering (SPS) technique at 1800°C under different sintering pressure. The grain boundaries of SiC and BCN phase could not be clearly distinguished for the ceramics sintered under 25MPa. When the pressure increased to 40MPa, SiC phase almost completely crystallized, and its grain size was less than 1μm. BCN phase were mainly distributed at boundary of SiC grain. Some amorphous structures were found in the sintered ceramics. Relative densities of the ceramics increased from 76.6% to 92.4%, and mechanical property values increased two or three times with the increase of sintering pressure. For the ceramics sintered under a pressure of 40MPa, flexural strength, fracture toughness, elastic modulus and Vickers’ hardness attained to 311.5MPa, 3.45MPam1/2, 133.0GPa and 3.68GPa, respectively. The mass of the SiBCN ceramics lose by several percent below 930°C in air, and then keep unchanged above 1100°C.