摘要
基于纳米复合Ti-Si-N薄膜硬度对界面相微结构及微尺度变化极为敏感的实验事实,定量表征了薄膜的硬度与氧杂质含量的关系.结果表明,与高纯度薄膜40-55 GPa高硬度比较,1%-1.5%的氧杂质含量导致薄膜的硬度下降到30 GPa左右.根据纳米晶界面原子模型和实验结果,氧杂质与纳米尺度界面交互作用所引发的微尺度缺陷是硬度下降的诱因,晶界面的氧杂质密度是薄膜高硬度损失程度的决定因素,单个纳米晶周围的氧杂质覆盖度达到10个原子以上时,薄膜的硬度只能达到30 GPa.
It was observed that the limitation hardness of nanocomposite Ti-Si-N coatings was very sensitive to microstructure of interface. It is shown that a dependent relation between hardness of Ti-Si-N coatings and oxygen impurity content of coatings. The 1%-1.5% of oxygen content in coatings causes a hardness decrease to about 30 GPa, as compared to 45-55 GPa for the relatively pure material. Based on an atomic model analysis, the decreasing of hardness caused by a small amount of oxygen impurities can be explained by oxygen atoms induce weakening of the Si3N4 interface which acts as a ＂glue＂ between the TiN nanocrystals. Further, It is concluded that density of oxygen atoms around grain boundary is a dominant factor on hardness degradation of the films, and the superhardness of above 40 GPa can not be achieved in coatings with above 10-oxygen atoms coverage around one TiN crystal.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2008年第3期287-290,共4页
Chinese Journal of Materials Research
基金
国家973重大基础研究项目2004CB619300
国家自然科学基金项目50601020和50671079
西安应用材料创新基金项目XMAM-200617
西安市科技攻关项目GG06057资助项目~~
关键词
材料科学基础学科
纳米复合薄膜
硬度
氧杂质
foundational discipline in materials science, nanocomposite coating, hardness, oxygen impurity
