促进剂及其优化对化学镀Ni-Sn-P层性能的影响

为了提高Ni-Sn-P化学镀层的沉积速率与镀液的稳定性,采用化学镀Ni-P合金复合稳定剂,研究了促进剂丙酸、甘氨酸、丁二酸对化学镀Ni-Sn-P镀层性能的影响,通过正交试验对3因素进行了优化,对镀速、孔隙率及显微硬度进行了测定.结果表明:甘氨酸、丙酸和丁二酸对镀层加速越快,镀层孔隙率越低、硬度越高;甘氨酸、丙酸对化学镀Ni-Sn-P加速显著;甘氨酸和丁二酸对镀层硬度都有所提高,而丙酸对Ni-Sn-P镀层硬度影响较小;甘氨酸、丙酸和丁二酸使化学镀Ni-Sn-P镀层的孔隙率都有不同程度降低,其中甘氨酸和丙酸作用显著;当甘氨酸为25 mg/L、丙酸为4 mL/L、丁二酸为2.5 g/L时,镀速提高至14～15 μm/h,硬度为480～550 HV0.5 N,孔隙率几乎为0.

Effect of Accelerators on the Properties of Electroless Ni-Sn-P Alloy Plating

The effects of methylacetic,glycocoll,and succinic acids as accelerators on the properties of electroless Ni-Sn-P coating were investigated in the presence of complex stabilizing agents used for electroless Ni-P plating,which was aiming at increasing the plating velocity and bath stability for the electroless Ni-Sn-P plating.Thus the dosages of the accelerators in the plating bath were determined making use of three-factor orthogonal tests,while the plating velocities at different conditions were measured,and the porosity and microhardness of the relevant Ni-Sn-P coatings were determined.Results indicated that the porosity and hardness of the Ni-Sn-P coatings were closely dependent on the accelerating effects of the accelerators.Namely,the accelerators of stronger accelerating effects contributed to generate the Ni-Sn-P coatings with lower porosity and higher microhardness.In particular,methylacetic and glycocoll acids were more effective in speeding the plating process,while glycocoll and succinic acids contributed to increase the microhardness of the Ni-Sn-P coatings to some extent.Moreover,all the three kinds of acids acted to reduce the porosity of the Ni-Sn-P coatings to varied degrees,and glycocoll and methylacetic acids were more effective in decreasing the porosity.The optimum contents of the accelerators glycocoll,methylacetic,and succinic acids in the plating bath were suggested as 25 mg/L ,4 mL/L,and 2.5 g/L,respectively.The corresponding Ni-Sn-P coatings deposited at the optimized conditions had a depositing rate about 14~15 m/h,microhardness from 480 HV to 550 HV,and were free of porosity.