气相分压对Co-Ni-Sb三元热电材料体系相平衡和相稳定性的影响  

Effect of gas phase pressure on phase equilibrium and phase stability of Co-Ni-Sb ternary thermoelectric material system

作　　者：张玉碧[1] 李长荣[2] 杜振民[2] 郭翠萍[2] 赵永涛[1] 汤安[1] 

机构地区：[1]河南工程学院机械工程学院,郑州451191 [2]北京科技大学材料科学与工程学院,北京100083

出　　处：《功能材料》2016年第8期8094-8103,共10页Journal of Functional Materials

基　　金：河南工程学院博士基金资助项目(D2015015)

摘　　要：依据Co-Ni-Sb三元系凝聚态的热力学优化评估和气相组分的热力学数据,利用Thermo-calc软件从热力学角度分析了气相压力对该体系中二元和三元体系的相平衡和相稳定性的影响。结果表明,气相压力减小到一定程度,Co-Ni、Co-Sb、Ni-Sb和Co-Ni-Sb体系中的化合物发生分解,出现气-液-固三相平衡区;计算的三相平衡温度-压力图(T-P图)表明各化合物都存在发生分解的临界压力和临界温度,在临界压力之上或临界温度以下,凝聚相间保持与常压下基本相同的相平衡关系。通过真空条件下Ni/ηCoSb3三元扩散偶测定的Co-Ni-Sb三元系1 073K等温截面,验证了计算的相平衡关系。研究结果为制备含Ni方钴矿热电材料ηCoSb3的工艺设计提供了热力学参考。According to the assessed and optimized thermodynamic parameters of the condensed phases and thoseof the gas-phase constituents of the Co-Ni-Sb ternary system, the effect of the gas-phase pressure on the phaseequilibria and the phase stability of the binary and ternary systems were analyzed thermodynamically. The resultsshow that the compounds of the Co-Ni, Co-Sb, Ni-Sb and Co-Ni-Sb systems start to pyrolyze when thegas-phase pressure decreases to a certain degree, and the gas-liquid-solid three-phase equilibrium zones appear.The calculated temperature-pressure diagrams （T-P diagram） of the compounds show that each compound has acritical minimum pressure value corresponding to a temperature values for its pyrolysis. Above the minimumpressure or below the temperature, the compound phase can keep the same phase relations as those at the atmospherepressure. Through the determination of 1 073 K isothermal-section of the Co-Ni-Sb ternary system invacuum condition by the three ternary diffusion couple Ni/7）CoSb3 , the calculated Co-Ni-Sb phase equilibria relationsis tested and verified at 1 073 K. The research results supply with the thermodynamical reference for thepreparation process design of the TjCoSbs skutterudite compound containing Ni.

关 键 词：热电材料 Co-Ni-Sb三元系 气相压力 相平衡 相稳定性 

分 类 号：TG146.2[一般工业技术—材料科学与工程]