铜合金的表面化学镀层制备与摩擦学性能研究

Preparation and Tribological Properties of Electroless Plating on Copper Alloy

采用化学复合镀的方法在铜合金表面制备了Ni-P-TiN-Re化学镀层,考察了NH_(4)ReO_(4)添加量和镀后热处理温度对化学镀层物相组成、显微形貌、硬度和摩擦学性能的影响。结果表明,热处理前不同NH_(4)ReO_(4)添加量的化学镀层表面主要由基体CuZn相和非晶态Ni相组成,镀液中加入不同添加量NH_(4)ReO_(4)后,镀层表面胞状颗粒减少,镀层致密程度相对有所提高;当NH_(4)ReO_(4)添加量为0、1、2、3和4 g/L时,化学镀层的截面厚度分别为11.9µm、15.8µm、16.2µm、15.6µm和15.3µm,磨痕宽度分别为136µm、148µm、128µm、93µm和125µm;添加NH_(4)ReO_(4)后,化学镀层的硬度都有不同程度提高,且NH_(4)ReO_(4)添加量越大则镀层硬度越高;NH_(4)ReO_(4)为3 g/L时,镀层磨痕宽度最小且磨痕相对更加平整,磨损率相对较低。热处理后,NH_(4)ReO_(4)为3 g/L时化学镀层在温度升高至400℃及以上时,化学镀层中开始出现晶态Ni_(3)P相,且随着热处理温度升高,化学镀层的显微硬度呈现先升高后减小特征,在温度为400℃时取得最大值(1178 HV),此时化学镀层的稳定摩擦系数最小、磨损率最低,具有最佳的耐磨性能,磨损机制为氧化磨损+黏着磨损。

Ni-P-TiN-Re electroless coatings were prepared on copper alloy by electroless composite plating,the effects of NH_(4)ReO_(4) addition and heat treatment temperature on the phase composition,mi‐crostructure,hardness and tribological properties of the electroless coatings were investigated.The re‐sults show that the surface of electroless coating with different addition of NH_(4)ReO_(4) before heat treat‐ment is mainly composed of CuZn phase and amorphous Ni phase.After adding different amount of NH_(4)ReO_(4) into the plating bath,the cellular particles on the surface of the coating decrease and the com‐pactness of the coating is relatively improved.When the addition amount of NH_(4)ReO_(4) is 0,1,2,3 and 4 g/L,the section thickness of the electroless coating is 11.9,15.8,16.2,15.6 and 15.3µm,The wear scar widths were 136,148,128,93 and 125μm,respectively.The results show that the hardness of the electroless coating increases with the addition of NH_(4)ReO_(4),and the hardness of the coating increas‐es with the addition of NH_(4)ReO_(4).When the content of NH_(4)ReO_(4) is 3 g/L,the width of wear scar is the smallest and the wear scar is relatively smooth and the wear rate is relatively low.After heat treatment,when the temperature of NH_(4)ReO_(4) is 3 g/L,crystalline Ni_(3)P phase begins to appear in the electroless coating when the temperature rises to 400℃.With the increase of heat treatment temperature,the mi‐crohardness of the electroless coating first increases and then decreases,and reaches the maximum val‐ue(1178 HV)at 400℃.At this time,the electroless coating has the lowest stable friction coefficient and wear rate,and has the best wear resistance,the wear mechanism is oxidation wear and adhesive wear.