汽车传动部件用40Cr钢表面Ni-nanoSiC复合镀层的制备

Preparation of Ni-nanoSiC composite coatings on surface of 40Cr steel used for automobile transmission parts

采用电沉积方法在汽车传动部件用40Cr钢表面制备Ni-nanoSiC复合镀层。以复合镀层中SiC质量分数和复合镀层的硬度作为指标,通过正交实验优化施镀工艺参数,得到最佳施镀工艺参数:搅拌速度为300 r/min、镀液中SiC颗粒质量浓度为20 g/L、温度为50℃、阴极电流密度为14 A/dm2。结果表明:采用最佳施镀工艺参数制备的Ni-SiC复合镀层表面平整、组织致密,其磨损机制为轻度磨粒磨损,平均摩擦因数约为0.45,低于40Cr钢的0.6;磨损量约为6.27 mg,相比40Cr钢约降低25.6%。Ni-nanoSiC复合镀层能够提供有效的防护,改善和提高40Cr钢的抗磨损性能。

Ni-nanoSiC composite coatings on the surface of 40Cr steel used for automobile transmission parts were prepared by using electrodeposition. The mass fraction of SiC in composite coatings and the hardness of composite coatings were taken as indexes, and the electroplating technological parameters were optimized through orthogonal experiment. The optimal electroplating technological parameters were as follows： stirring rate 300 r/min, SiC particle concentration in bath 20 g/L, temperature 50 ~C, cathode current density 14 A/dm2. Results show that the Ni-nanoSiC composite coating prepared with optimal electroplating technological parameters has smooth surface and compact structure, its wear mechanism is mild abrasive wear, the average friction coefficient is about 0.45, lower than that of 40Cr steel about 0.6. And the wear loss is low, about 6.27 mg, which is reduced by 25.6% compared with that of 40Cr steel. The Ni-nanoSiC composite coating can offer effective protection and improve the wear resistance of 40Cr steel.