AlN/SiO_2纳米多层膜的超硬效应与高温抗氧化性  

Superhardness Effect and High Temperature Oxidation Resistance of AlN/SiO_2 Nano-multilayers

作　　者：吴莹[1] 赵文济[1] 孔明[1] 黄碧龙[1] 李戈扬[1] 

机构地区：[1]上海交通大学金属基复合材料国家重点实验室,上海200030

出　　处：《无机材料学报》2008年第3期562-566,共5页Journal of Inorganic Materials

基　　金：国家自然科学基金(50571062)

摘　　要：采用反应磁控溅射法制备了一系列不同SiO_2层厚的AlN/SiO_2纳米多层膜,利用X射线衍射仪、高分辨透射电子显微镜、扫描电子显微镜和微力学探针表征了多层膜的微结构和力学性能,研究了多层膜微结构与力学性能随SiO_2层厚的变化,考察了AlN/SiO_2纳米多层膜的高温抗氧化性.结果表明,受AlN层晶体结构的模板作用,溅射条件下以非晶态存在的SiO_2层在厚度<0.6nm时被强制晶化为与AlN相同的六方结构赝晶体,并与AlN形成共格外延生长结构,多层膜相应产生硬度升高的超硬效应.SiO_2随自身层厚的进一步增加又转变为以非晶态生长,致使多层膜的外延生长结构受到破坏,其硬度也随之降低.高温退火研究表明,高硬度的AlN/SiO_2纳米多层膜的抗氧化温度为800℃,与AlN单层膜相当.SiO_2层的加入尽管能使多层膜获得较高硬度,但是并不能提高其抗氧化温度.A series of AlN/SiO2 nano-multilayers with different individual SiO2 layer thicknesses were prepared by reactive magnetron sputtering. The microstructure and mechanical properties of these multilayers were studied by X-ray diffraction, high-resolution transmission electron microscope, scanning electron microscope and nanoindentation. The influence of SiO2 layer thickness on the microstructure and mechanical properties of AlN/SiO2 nano-multilayers was studied, and the high temperature oxidation resistance was investigated. The SiO2 layer is usually amorphous under sputtering condition. Results show that when its thickness is less than 0.6nm, the SiO2 layer is forced to crystallize into hexagonal pseudocrystal structure and grows epitaxially with AlN, and the multilayers exhibit superhardness effect. With a further increase in its layer thickness, SiO2 layer transforms into amorphous structure and blocks the coherent growth of multilayers, accompanied with a decline in the film hardness. The results of high temperature annealing test indicate that the oxidation resistance temperature for AlN/SiO2 nano-multilayers with high hardness is up to 800℃, equivalent to that for the AlN monolayer. The addition of SiO2 layer can improve the hardness of multilayers, but it will not remarkably improve the high temperature oxidation resistance of films.

关 键 词：AlN/SiO2纳米多层膜 外延生长 超硬效应 抗氧化性 

分 类 号：O484[理学—固体物理]