化学镀镍稳定剂的筛选

Screening Stabilizers for Electroless Nickel Plating

目前,关于稳定剂对化学镀镍的影响研究不系统且不够深入。在化学镀镍基础镀液中分别加入硫脲、硫代硫酸钠、碘酸钾、DL-半胱氨酸、苯骈三氮唑和苯并咪唑等稳定剂,在45碳钢表面化学镀镍,采用施镀前后的质量变化计算镀速,采用磷钼钒黄分光光度法测定镀层磷含量,采用EDTA标定法测定镀液稳定常数,采用锉刀试验测试镀层结合力,研究了各种稳定剂对镀速、镀层结合力、镀层磷含量、镀液稳定性的影响。结果表明:含硫稳定剂在施镀过程中会产生含硫物质,会破坏镀液稳定性,不宜使用;添加50.0 mg/L碘酸钾或10.0 mg/L苯骈三氮唑稳定剂时,镀液稳定常数最高,为0.98;添加4.0 mg/L苯并咪唑稳定剂时镀速最快,达17.75μm/h;添加50.0 mg/L碘酸钾稳定剂时,镀层磷含量最高,达12.22%。

Stabilizers including thiourea,sodium thiosulfate, potassium iodate, DL- cysteine,benzene benzotriazole and benzimidazole were separately added into the electroless Ni plating bath so as to prepare electroless Ni coatings on 45 steel. The plating rate was determined by taking into account the variation in the mass of the Ni coatings. The P content of the coating and the stabilization constant of the platingbath were respectively determined by vanadium molybdenate phosphate spectrophotometry and ethylene diamine tetra-acetic acid calibration method,and the adhesion force of the Ni coatings was measured by file test. Furthermore,the effect of various stabilizers on the plating rate,adhesion force and P content of the Ni coatings as well as the stability of the plating bath was investigated. It was found that the S-containing stabilizers were unsuitable for electroless Ni plating,because they generated S-containing species and caused damage to the stability of the plating bath.The plating baths with 50. 0 mg / L potassium iodate or 10. 0 mg / L benzene benzotriazole exhibited the highest stabilization constant of 0. 98. The maximum plating rate of 17. 75 μm / h was achieved when 4. 0 mg / L benzimidazole was added in the plating bath.Moreover,the Ni coating made from the plating bath containing50. 0 mg / L potassium iodate exhibited the highest P content of12. 22%( mass fraction).