Microhardness Improvement of Ni-W/SiC Composite Coatings by High Frequency Induction Heat Treatment
Microhardness Improvement of Ni-W/SiC Composite Coatings by High Frequency Induction Heat Treatment
复制标题
DOI：
10.1149/2.0661908jes
复制
发表时间：
2019
影响因子：
3.9
通讯作者：
Changwei Su;Linfu Zhao;Yang Bai;L. Tian;Bixia Wen;Junming Guo
中科院分区：
文献类型：
--
作者：
Changwei Su;Linfu Zhao;Yang Bai;L. Tian;Bixia Wen;Junming Guo
电沉积Ni-W合金涂层被认为是最适合替代对环境有害的六价硬铬涂层的涂层之一。但要提高其显微硬度，细化其晶粒，必须进行高温热处理。采用交替高频感应热处理(HFI-HT)技术，对从柠檬酸铵溶液中电沉积的含有悬浮绿色碳化硅颗粒的Ni-W/碳化硅复合镀层的表面显微硬度进行了改善。HFI-HT后可观察到非晶态结构向晶态结构的转变。当功率密度为21W mm−2时，延长对S的诱导时间，或将功率密度调至42W mm−2时，4 S可析出Ni6W6C相而不是Ni4W相，而在900℃时可析出Ni6W6C和Ni4W两种相，当功率密度为21W mm−2时，可使Ni-W/SiC复合镀层的显微硬度提高到1100HV，与硬质合金镀层相当。
Electrodeposited Ni-W alloy coating is considered as one of the most suitable candidate to replace the environmentally hazardous hexavalent hard chromium coatings. However, it is necessary to carry out heat-treatment at a high temperature to improve its microhardness and refine its grain. In the present work, an alternative high frequency induction heat-treatment (HFI-HT) technology was used to improve surface microhardness of Ni-W/SiC composite coatings, which were electrodeposited from an ammonium-citrate bath, containing suspended green SiC particles. Transformation of amorphous to crystalline structure can be observed after HFI-HT. The precipitation of a Ni 6 W 6 C phase rather than a Ni 4 W phase occurs by prolonging induction time to 64 s at a power density of 21 W mm− 2 or turning power density up to 42 W mm− 2 for 4 s. While the two phases of Ni 6 W 6 C and Ni 4 W can be precipitated at 900 C. The microhardness of Ni-W/SiC composite coatings can be improved up to 1100 HV with HFI-HT at 21 W mm− 2 for 8 s, which is comparable to that of hard chrome coatings.