Ni-SiC纳米复合镀层耐高温氧化性能的分析

Analysis of Pyro-oxidation Resistance of Ni-SiC Nano Composite Coatings

对Watts镀镍层以及添加纳米SiC的复合镀镍层的耐高温氧化性能进行了比较分析。热重和差示扫描量热试验表明 ,添加纳米SiC并不能明显改善镀层的耐高温氧化性能 ,但添加 15g L的纳米SiC可以提高复合镀层晶面结构的热稳定性 ,将(111)晶面向 (2 0 0 )晶面转化的温度由原来的 32 5°C提高到 36 5°C。X射线衍射分析表明 ,添加纳米SiC会改变镀镍层的结晶取向 ,由原来以 (2 0 0 )为主 ,(111)为辅转变为以 (111)为主 ,(2 0 0 )为辅。经 4 0 0°C高温氧化处理后镀层的晶面结构以 (2 0 0 )为主 ,(111)为辅 ;经 80 0°C高温氧化出现氧化产物NiO和Fe3O4 。

The pyro-oxidation resistance of electrodeposited Watts Ni coating and Ni-SiC nano composite coatings is analyzed. The results of TG and DSC show that addition of SiC can not obviously improve the pyro-oxidation resistance of the coatings, but the thermo-stability of the crystal face structure of the composite coatings can be improved and the inversion temperature from crystal face(111) to (200) can be raised from 325 °C to 365 °C , when 15 g/L of nano SiC is added. XRD analysis indicates that crystal orientation of nickel coatings will be changed from main(200) with auxiliary (111) to its opposite when nano SiC is added. If pyro-oxidized at 400 °C , the crystal face structure of the coatings will be transformed to main(200) with auxiliary (111), and oxides like NiO and Fe 3O 4 will appear after oxidation at 800 °C .