Effect of MoSi_2 content on dielectric and mechanical properties of MoSi_2/Al_2O_3 composite coatings  

MoSi_2含量对MoSi_2/Al_2O_3复合涂层介电与力学性能的影响(英文)

作　　者：WU Zhi-hong ZHOU Wan-cheng LUO Fa ZHU Dong-mei 武志红;周万城;罗发;朱冬梅(西北工业大学凝固技术国家重点实验室,西安710072)

机构地区：[1]State Key Laboratory of Solidification Processing,Northwestem Polytechnical University,Xi’an 710072,China

出　　处：《Transactions of Nonferrous Metals Society of China》2012年第1期111-116,共6页中国有色金属学报（英文版）

基　　金：Project (50572090) supported by the National Natural Science Foundation of China;Project (KP200901) supported by the States Key Laboratory of Solidification Processing in NWPU, China

摘　　要：Molybdenum disilicide （MoSi2） sheath and aluminum oxide （Al2O3） core blended powders were fabricated by spray drying. A derived coating material was produced for the application as microwave absorbers using the as prepared powders by atmospheric plasma spray （APS） technology. The effects of MoSi2/Al2O3 mass ratio on the dielectric and physical mechanical properties of the composite coatings were investigated. When the MoSi2 content of the composites increases from 0 to 45%, the flexure strength and fracture toughness improve from 198 to 324 MPa and 3.05 to 4.82 MPa-m1/2 then decline to 310 MPa and 4.67 MPa-m1/2, respectively. The dielectric loss tangent increases with increasing MoSi2 content, and the real part of permittivity decreases conversely over the frequency range of 8.2-12.4 GHz. These effects are due to the agglomeration of early molten MoSi2 particles and the increase of the electrical conductivity with increasing MoSi2 content.通过喷雾干燥法制备MoSi2包覆Al2O3的壳核结构混合粉,利用该混合粉以等离子喷涂技术制备MoSi2/Al2O3复合涂层材料。研究MoSi2/Al2O3质量比涂层材料的力学和介电性能的影响。结果表明:随着MoSi2含量从0增加到45%,复合材料的抗弯强度和断裂韧性分别从198MPa和3.05MPa·m1/2增加到324MPa和4.82MPa·m1/2,随后又降到310MPa和4.67MPa·m1/2。在8.2-12.4GHz微波频率波段内,随着MoSi2含量的增加,复合材料的介电损耗增加,而介电常数的实部却呈减小趋势。这主要是由于MoSi2颗粒熔化后的凝聚及导电网络结构的形成导致电导率的增加引起的。

关 键 词：MoSi2/Al2O3 composite coating atmospheric plasma spraying mechanical properties dielectric properties 

分 类 号：TG174.4[金属学及工艺—金属表面处理]