Microstructure of Mo-Si-C-N anti-oxidation coatings on C/C composites
The microstructures of a Mo-Si-C-N coating, synthesized in a flowing nitrogen atmosphere by fused slurry, have been characterized in detail by means of X-ray diffractometry, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that the Mo-Si-C-N coating has a four layer structure consisting of a SiC bonding layer, MoSi2/Si main layer, sialonceramic subsurface layer and SiC nanowire surface layer. The SiC bonding layer formed by the diffusion of Si and C atoms is very dense and consists of β-SiC nanograins. No crack or defect is found on the two-sided interface of the SiC bonding layer, indicating that the SiC bonding layer has strong bonding with the C/C composite substrate and MoSi2/Si main layer. The MoSi2/Si main layer is covered with a sialon-ceramic subsurface layer of about 5 μm in thickness. The sialonceramic subsurface layer plays an important role in further improving the oxidation resistance of the Mo-Si-C-N coating due to its excellent anti-oxidation properties. β-SiC nanowires with a substructure of twin and stacking faults growing along the <111> direction constitute the surface layer of the Mo-Si-C-N coating with a thickness of about 10 μm. To minimize the surface energy as well as total free energy, the SiC nanowires have surfaces with a fixed faceted angle, which accords with the intersection angle of the adjacent (111) close-packed plane in the faced-centred cubic structure.
Zhonghong Lai Songhe Meng Jingchuan Zhu Fuqiang You
School of Materials Science & Engineering, Harbin Institute of Technology, Harbin, 150001,P.R.China Research Center for Composite Materials, Harbin Institute of Technology, Harbin 150001,P.R.China Shanghai Key Laboratory of Development and Application for Metal-Functional Materials, Tongji Univer
国际会议
桂林
英文
1-13
2010-11-16（万方平台首次上网日期，不代表论文的发表时间）