【作者】 王勇；

【导师】 曾振欧；

【作者基本信息】 华南理工大学 ， 应用化学， 2011， 硕士

【摘要】 高磷化学镀镍层具有非晶态构型,不但具有优良的耐蚀性和耐磨性,还具有稳定的非磁性、高电阻率、低温度系数及耐热等性能,是一种优良的功能性镀层,广泛应用于计算机硬盘、磁屏蔽设备、电子工业、石油化工管道设备、汽车零部件等方面。但是通常酸性高磷化学镀镍的施镀温度较高,降低镀液温度不仅可以提高镀液稳定性、降低生产成本,而且可以减少镀液挥发量,从而起到节约能源和保护环境的双重功效。中温高磷化学镀镍工艺的研究具有重要的实际意义和良好的应用前景。课题通过对镀液组分(主要是稳定剂、络合剂、加速剂及光亮剂)及操作条件(温度、pH)进行系统的研究,考察其对镀层沉积速度、磷含量以及镀层性能(孔隙率、结合力、耐蚀性等)的影响,对各个组分的种类及含量进行优选,以提高镀层沉积速度,最后通过正交实验得到中温高磷化学镀镍的最优配方。最佳工艺配方为:主盐和还原剂摩尔比为0.34;20.4g/L三水合乙酸钠为缓冲剂;10 mg/L KI为稳定剂;8 mL/L乳酸+0.02 mol/L柠檬酸+0.04 mol/L苹果酸+0.05 mol/L丙二酸为复合络合剂;0.06 mol/L丁二酸+0.04 mol/L对甲苯磺酸钠为复合加速剂;温度75±1℃;pH 4.70。最优工艺组成条件下,镀液PdCl2加速实验稳定时间达1650s,镀层沉积速度7.18μm/h,镀层磷含量10.89 w.t.%,镀片外观光亮平整、细致平滑,结合力良好,硬度高,孔隙率低至0.24个/cm2,镀层耐硝酸色变时间为180s,耐中性盐雾时间24h以上,所得到的中温高磷试片整体性能优良。光亮剂的加入可以使镀层外观更光亮细致,但同时也使镀层耐蚀性下降,应选择性使用。周期实验表明,中温高磷化学镀镍镀液稳定,镀液寿命可达8MTO以上,浓缩液组分及周期添加方式对镀液使用寿命、镀速及镀层性能均会产生影响。将中温高磷化学镀镍液与市场上某高温高磷化学镀镍产品性能进行了详细的对比,中温高磷镀层的整体性能占优,可以以较薄的镀层实现与高温高磷较厚镀层一样的性能,应用前景良好。课题通过系统的研究得到了镀层性能良好、实际可行的中温酸性高磷化学镀镍工艺,为实现工业应用提供有参考价值的可行性工艺方案。更多还原

【Abstract】 The high-phosphorous electroless nickel deposits have amorphous structure. Besides the excellence in wearing and corrosion resistance, Ni-P electroless plating deposits also have non-magnetism, high resistivity, the low resistance temperature coefficient and thermal stability, etc.So that they are widely applied in computer hard, magnetic shielding equipment, electronic industry, petrochemical industry and auto industry etc. But the operation temperature in high-phosphorous electroless nickel plating is usually high. The lower temperature will not only enhance the stability of plating solution,save energy source and reduce production cost, but also decrease the volatilization of solution and relieve environment pollution. Therefore, middle-temperature and high-phosphorus electroless nickel plating technology has a great significance of theory and practice.The primary composition (stabilizer, complexing agent, accelerator, brightener, etc.) of eleetroless nickel plating bath,the condition of operation (temperature, pH) ,which influence the technology of middle-temperature and high-phosphorus eleetroless nickel-phosphorus alloy, are studied systematically with condition experiments and the orthogonal experiments in this article. Based on the analysis of deposition rate, phosphorus content, microhardness, adhesive strength, porosity and corrosion-resistant property of Ni-P alloy coating, the preferable conditions of the bath composition and condition of operation are screened out.The research results show that all of primary composition in the electroless nickel solution may influence the technology; complexing agent and accelerator are the most important factors. The most promising choice is the use of appropriate complexing agents or accelerators to design the procedures of eleetroless plating at medium or low temperature. In the proeess of operation,temperature and pH value may influence the technology greatly . The questing for middle-temperature and high-phosphorus eleetroless nickel technology leads to the optimal formula as follows:Proportion of nickel su1phate and sodium hypophosphate 0.34; Sodium acetate 20.4 g/L; Stabilizer KI 10 mg/L;Composite complexing agents: lactic acid 10ml/L , citric acid 0.02 mol/L, malic acid 0.04 mol/L, malonic acid 0.05 mol/L; Composite aeeelerators: succinic acid 0.06 mol/L, toluene sulfonic acid 0.04 mol/L; Temperature 75±1℃; pHvalue 4.70. Under the optimal formulation, the bath stabilization time is up to 1650 s, the deposition rate is 7.18μm/h,and phosphorus content is 10.89 w.t.%; The deposit is bright and level, porosity is only 0.24 pore/cm~2,and has 180s plus spot corrosion time in nitrate solution and 24h of salt spray corrosion resistance. In sum,the integrated properties of coating is very excellent.The addition of brightener makes the coating appearance brighter and meticulous, but also decreases the corrosion resistance of the coating, it should be selectively used.The metal turnover test experiments show that the middle-temperature and high-phosphorus electroless nickel plating bath is stability, plating bath life is up to 8MTO, the composition of concentrate and supplement method will largely affect the deposition rate, bath life and deposit properties.A detailed comparison between middle-temperature and high-phosphorus electroless nickel plating bath and high-temperature and high-phosphorus electroless nickel plating product of market is carried out,the integrated properties of the former is better than the latter’s,thinner coating can achieve the same performance as the thicker coating of high-temperature and high-phosphorus electroless nickel plating, the application prospects is good.A realistic middle-temperature and high-phosphorus electroless nickel plating technology with good performance is obtained by systematically studying, providing a reference value for industrial applications.更多还原