纳米TiC颗粒对Ni-TiC复合镀层组织与性能的影响

采用双脉冲复合电镀技术,在瓦特型镀液中,制备含微-纳米TiC颗粒的Ni基复合镀层。研究镀液中纳米TiC添加量对复合镀层微观形貌、组织结构、硬度、摩擦和抗氧化性能的影响。结果表明:镀液中添加纳米TiC后,Ni-TiC复合镀层表面出现团聚、致密度降低,复合镀层的组织为Ni和TiC;随镀液中纳米TiC添加量的增加,复合镀层的显微硬度呈先增后降的趋势,而摩擦因数则先降后升;当纳米TiC颗粒添加量为6.0g/L时,复合镀层显微硬度最大,为445HV,摩擦因数较小,为0.22,磨损机制以磨料磨损为主;在900℃,100h氧化条件下抗氧化性能最佳,氧化增重为6.828mg/cm~2,为微米复合镀层的0.5倍。

Effect of Nano-TiC Particles on Microstructure and Properties of Ni-TiC Composite Coatings

Ni based composite coatings containing micro and nano TiC particles were prepared by dipulse electrodepositing in Watt's nickel solution.The effect of nano-TiC content in the solution on the micro morphology,microstructure,hardness and wear resistance of composite coatings was investigated.The results show that the agglomeration of composite coatings of Ni-TiC appears and the density decreases by adding nano-TiC particles in electrolyte,the microstructure of coatings consists of Ni and TiC phase;the hardness of composite coatings firstly increases and then decreases with increasing the content of nano-TiC in bath;however,the friction coefficient of coatings firstly decreases and then increases,the maximum value of microhardness of coating with 445HV is achieved when containing 6.0g/L nano-TiC in bath,at the same time,the smaller friction coefficient of coating is about 0.22.The wear mechanism is mainly abrasive wear.Coatings under the oxidation condition at 900℃ for 100h show the best oxidation resistance which the mass gain with 6.828mg/cm2 is 1/2 of that of micro-TiC composite coating.