脉冲电刷镀Ni-Co镀层及其硬度的研究

目的优选脉冲参数,获得具有较高显微硬度的电刷镀Ni-Co合金镀层。方法采用脉冲电源制备电刷镀Ni-Co合金镀层,以显微硬度为性能指标,对比考察CoSO_4浓度、电压、频率和占空比对Ni-Co合金镀层的影响,并研究了最优工艺参数下Ni-Co-MoS_2复合镀层硬度随MoS_2浓度的变化情况。结果电刷镀Ni-Co合金镀层的显微硬度随镀液中CoSO_4浓度的升高先增大后减小,当CoSO_4质量浓度为40 g/L时,镀层硬度达到最大值597.4HV。在4~12 V范围内,电压的增大以及占空比的减小,会使镀层硬度增大。随着频率的增大,镀层硬度呈增大趋势;频率达到1200 Hz后,镀层硬度轻微下降。加入一定量MoS_2,复合镀层硬度先增后减。结论在CoSO_4质量浓度为40 g/L、电压12 V、频率1000 Hz、占空比0.5的条件下,制备出的镀层硬度最大。与未加MoS_2的电刷镀Ni-Co镀层相比,Ni-Co-MoS_2复合镀层硬度有所下降;随着MoS_2浓度增加,复合镀层硬度先增大后减小,当MoS_2质量浓度为20 g/L时,复合镀层硬度达到最大值547HV。

Ni-Co Alloy Coatings Prepared by Pulse Brush Electroplating and Their Microhardness

The work aims to optimize pulse parameters and prepare brush-plated Ni-Co alloy coatings of high microhardness. Brush plated Ni-Co alloy coatings were prepared with pulsed power supply, and effects of CoSO4 concentration, voltage, frequency and duty cycle on microhardness of Ni-Co alloy coatings were compared with microhardness as performance index. Variation of the microhardness of Ni-Co-MoS2 composite coatings as a function of MoS2 concentration provided with optimum technique parameters was studied. With the increase of CoSO4 concentration, the microhardness of Ni-Co alloy coatings first increased and then decreased, and reached 597.4HV, the maximum when CoSO4 concentration was 40 g/L. In the range of 4~12 V, the microhardness of the coatings increased as the voltage increased and duty cycle decreased. The microhardness of the coatings tended to increase as the frequency increased, and it decreased slightly when the frequency reached 1200 Hz. After a certain amount of MoS2 was added, microhardness of the coatings first increased and then decreased. Provided with CoSO4 concentration of 40 g/L, voltage of 12 V, frequency of 1000 Hz and duty ratio of 0.5, microhardness of the composite coatings reaches the maximum. Compared with the Ni-Co coatings free from MoS2, microhardness of Ni-Co-MoS2 composite coatings decreases. With the increase of MoS2 concentration, the microhardness of composite coatings first increases and then decreases. When the MoS2 concentration is 20 g/L, the microhardness reaches the maximum, 547HV.