【作者】 贺同强；

【导师】 姚素薇；

【作者基本信息】 天津大学 ， 应用化学， 2007， 硕士

【摘要】 珍珠镍外观为乳白色,光泽柔和,内应力低,防腐蚀性好,是一种优良的防护装饰性镀层,已广泛应用于汽车装饰、电子产品、日用五金等行业中。本文在大量实验的基础上,确定了珍珠镍电镀添加剂的组成,根据其在镀液中作用的不同,可分为三种成分:载体剂、走位剂和珠光剂。载体剂主要为镀镍初级光亮剂,作用是细化晶粒,减小镀层的内应力,提高或调节镀层的光泽。走位剂主要有烯丙基磺酸钠、不饱和烷基磺酸盐等组成,作用为提高低电流密度区的珠光效果。珠光剂是影响镀层珠光效果的主要添加剂,本文通过实验开发了两类珠光剂,在镀液中添加后均能够获得珠光效果良好的镀镍层。第一类为不含有非离子表面活性剂的珠光剂。该添加剂主要由琥珀酸酯盐类阴离子表面活性剂、羧酸盐类阴离子表面活性剂和季铵盐类阳离子表面活性剂等按一定比例混合组成。第二类是由非离子表面活性剂和特殊表面活性剂复配而成。这两类珠光剂加入镀液后,均能形成细小的乳滴,在电镀过程中,乳滴吸附在电极表面,阻止镍离子的正常沉积,导致镀层表面出现了无数的凹坑。文中考察了添加剂用量、镀液温度与pH值、电流密度等工艺条件对珍珠镍镀层的影响,确定了最佳的工艺条件,并对珍珠镍镀层的性能进行了研究。扫描电镜下观察到珍珠镍镀层表面有无数重叠的圆形凹坑,这些凹坑在光照下会发生较强的漫反射,在宏观上出现柔和的珍珠效果。阳极极化曲线测试结果表明,珍珠镍镀层的耐腐蚀性优于普通光亮镍镀层。阴极试验法测试结果表明,珍珠镍镀层与基体结合力良好。制备的珍珠镍镀层具有较高的表面活性,适于进一步加工,如镀铬、镀银等。通过挂片实验考察了镀液的出光时间和稳定性,实验结果表明采用上述添加剂的珍珠镍镀液出光时间约为3～4分钟,镀液稳定性良好,可以连续施镀14～15个小时,而且使用后的镀液不需立即用活性炭处理,只在常规过滤后补加入适当量的有机添加剂即可继续使用。更多还原

【Abstract】 The satin nickel coating is an excellent ornamental coating owing to its soft luster appearance, low body stress and good wear resistance, and it has been applied to the decorative parts in automobile, electronic product and commodity metal.In the text the ingredients of additives of the decorative satin nickel electro-deposition have been ascertained through a large quantity of experiments. According to the different function in the electroplating bath the additives have been divided into three components which are the carrier additives, the assistant additives and the satin finish additives. The carrier additives is composed of basic brighter of nickel coating, the main function of which is to reduce the crystalloid size of nickel coating, to make the nickel coating appear certain brightness, to reduce the stress and to improve the tractility of nickel coating as well. The assistant additives are sodium allylsulfonate and sodium unsaturated alkylsulfonate, the function of which is to expand technological current density range. The satin finish additives are the most important to the appearance of the satin nickel electroplating. In the text two kinds of the satin finish additives are studied. With each kind of the satin finish additives in the electroplating bath an even satin-finished nickel was achieved. One of the satin finish additives contains a sulfosuccinic acid anion surfactant, a carboxylic ion anion surfactant and one quaternary ammonium cathode surfactant, which did not contain nonionic surfactant. The other contains a nonionic surfactant and a specific surfactant. With the satin finish additives in the electroplating bath the small emulsified drops are produced. During the nickel depositing the small emulsified drops are absorbed on the surface of the cathode and prevent nickel ion depositing. Then the pits are formed on the surface of the cathode.In the text the effects of technological parameters on the coating appearance have been researched,including content of additive, temperature and pH of the bath, current density etc. Using the SEM techniques a lot of round pits were observed on the surface of satin nickel coating. Because of the pits the diffuse reflection occurred under the light and the satin appearance was obtained. The results of polarization curves show that the corrosion resistance of the satin nickel coating is more favorable than semi-bright nickel. The result of adhesive force test shows that the adhesive force between the coating and the substrate is excellent.Using small trough experiments the time to achieve satin finish appearance and the stability of electroplating bath were tested. The results showed that the satin nickel coating could be obtained in 3 minutes to 4 minutes and the electroplating bath could last for about 15 hours. Without active carbon treating after using, the electroplating bath could be used again with adding suitable quantity of additives after the normal filtrating.更多还原