摘要
在高温（１４００℃）和超高压（４．２ＧＰａ）条件下制备部分稳定ＺｒＯ_２增韧的Ｓｉ_３Ｎ_４中介结合的聚晶立方氮化硼（ＰＣＢＮ），研究了中介相中ＺｒＯ_２的相变及增韧机理．在ＰＣＢＮ中加入少量Ａｌ粉，可阻止ｔ－ＺｒＯ２形成，达到利用部分稳定的ＺｒＯ２的ｔ－ｍ相变增韧中介相Ｓｉ３Ｎ４的目的．ＺｒＯ_２的ｔ－ｍ相变量在稳定剂Ｙ_２Ｏ_３含量为２．０％（摩尔分数）时达到最大值，ＰＣＢＮ具有较高的抗压强度和磨耗比．ＺｒＯ２对中介相的增韧机理为相变增韧与微裂纹增耕作用的叠加．
Si_3N_4 bond polycrystalline cubic boron nitride (PCBN) were prepared at high temperature (1400℃) and ultrahigh pressure (4.2GPa). Phase transformation of ZrO2 and toughening mechanism were investigated by XRD, SEM and the measurement of mechanical properties. The results showed that Al addition can prevent t'-ZrO2 forming and PCBN are toughened with Y2O3 partially stabilized ZrO2. While content of Y2O3 is 2.0%(mole fraction), the optimum content of phase transformation from tetragonal to monoclinic ZrO2 is obtained and PCBN has high compressive strength and high G-ratio. The toughness increase comes from t-m transformation and toughening with micro-cracks.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2000年第6期595-598,共4页
Chinese Journal of Materials Research
基金
国家自然科学基金资助项目! 59382013.
