Journal of Inorganic Materials

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Superhardness Effect and High Temperature Oxidation Resistance of AlN/SiO2 Nano-multilayers

WU Ying, ZHAO Wen-Ji, KONG Ming, HUANG Bi-Long, LI Ge-Yang   

  1. State Key Laboratory of Metal Matrix Compositions, Shanghai Jiaotong University, Shanghai 200030, China
  • Received:2007-06-12 Revised:2007-09-05 Online:2008-05-20 Published:2008-05-20
  • Contact: LI Ge-Yang

Abstract: 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.

Key words: AlN/SiO2 multilayer, epitaxial growth, superhardness effect, oxidation resistance

CLC Number: 

  • O484