【作者】 王鹤坤；

【导师】 贺岩峰；

【作者基本信息】 长春工业大学 ， 化学工程， 2011， 硕士

【摘要】 将锡引入到化学镀Ni-P合金中形成Ni-Sn-P合金镀层是改善其耐蚀性、耐热性和可焊性等的有效方法。本文主要探讨了工艺条件和镀液组分对化学镀Ni-Sn-P合金镀速、组成、表面形貌的影响,并考察了锡对镀层的耐蚀性和可焊性的影响。在此基础上向镀液中加入稀土元素,考察了稀土元素对镀层组成和耐蚀性的影响,并探讨了化学镀Ni-Sn-P的沉积机理。论文首先考察了四价锡和二价锡化学镀Ni-Sn-P中还原剂、配位剂、pH、锡盐浓度对镀速、镀层组成、表面形貌的影响,以及不同Sn含量的Ni-Sn-P合金镀层的耐腐蚀性能和可焊性。实验结果表明：化学镀Ni-Sn-P中,镀速随着镀液中还原剂的增加而增加,镀层中P含量随还原剂的增加而增加,Sn含量随还原剂的增加而有所降低,四价锡中还原剂含量为35g/L时,镀层的表面形貌最佳,二价锡中,还原剂含量为20g/L时,镀层的表面形貌最佳；化学镀Ni-Sn-P中,镀速随着镀液中配位剂含量的增加而降低,镀层中P、Sn含量均随配位剂柠檬酸的增加而增加。随着配位剂浓度的增加镀层的表面形貌结晶细化,四价锡中,30g/L时镀层最致密,性能最好；二价锡中40g/L时,镀层最致密。化学镀Ni-Sn-P中,镀速随着镀液中锡盐含量的增加而降低,5g/L时,镀速最佳,Sn含量随着锡盐含量增加而增加,P含量随着镀液中锡盐含量增加而减小。镀层的表面形貌,随镀层中锡含量的增加逐渐细化；四价锡化学镀Ni-Sn-P中,镀速随着温度的升高而升高, P、Sn含量均随温度的升高而有所升高,88℃-90℃时镀速、表面形貌最佳；化学镀Ni-Sn-P中,镀速均随着pH值升高而升高,镀层中的P、Sn含量随pH变化,上下波动,四价锡中,pH值4.5时,表面形貌最佳,二价锡中pH 9-10时,表面形貌最佳；化学镀Ni-Sn-P的耐蚀性相对于化学镀Ni-P镀层更好,并且锡含量为20g/L时耐蚀性最好。第五章研究了化学镀Ni-Sn-P技术在微电子领域中的应用,并成功地在引线框架上制备了具有良好可焊性的Ni-Sn-P镀层,所用镀层P含量11-13%,Sn含量1-2%左右。第六章探讨了二价锡和四价锡化学镀Ni-Sn-P沉积机理的不同。第七章在化学镀Ni-Sn-P工艺基础上加入稀土元素,制备了Ni-Sn-P-RE复合镀层,讨论了稀土元素对镀速、镀层组成、表面形貌和镀层耐蚀性的影响。实验结果表明：添加稀土铈后镀层的耐蚀性比未加入稀土铈的Ni-Sn-P镀层耐蚀性增加。当碳酸铈浓度为0.03g/时,耐蚀性最好。添加稀土元素的镀层与未加入稀土的Ni-Sn-P镀层相比,镀层中Sn的含量增加,P的含量降低。添加稀土氧化镧和碳酸铈后,镀速随着镀液中稀土含量的增加而逐渐减小。添加稀土氧化钕后,镀层的沉积速率随着镀液中稀土含量的增加,先增大后降低,在0.03g/L时达到最高点。添加稀土元素后镀层的表面形貌变得平整,光滑,胞状结构趋于消失。更多还原

【Abstract】 This is a effect method that tin will be introduced to the electroless Ni-P alloy platings forming Ni-Sn-P alloy coatings. Ni-Sn-P coatings will have good properties in the corrosion resistance, heat resistance and weldability, etc. This paper mainly discussed the effect of process conditions and elements on the deposition rate, composition and surface morphology, and the effects of tin concentration in bath on corrosion resistance and weldability of the coatings. Then the rare earth elements were introduced to Ni-Sn-P alloy. The effect of rare earth on corrosion resistance and composition of the plating layer were discussed. The mechanism of electroless Ni-Sn-P were analysed.Firstly, the effect of concentrations of reducing agent, coordination agent and tin in bath on deposition rate, composition of plating layer and surface morphology, and the effects of tin concentration in bath on corrosion resistance and weldability of the coatings were studied on the four valence tin and bivalent tin of electroless Ni-Sn-P. The results showed that:the tin content in the deposit decreased with an increase in reducing agent concentration in the bath, the phosphorus content in the deposit increased with an increase in reducing agent concentration in the bath, when the reducing agent concentration was 35 g/L,the surface appearance is best in the four valence tin electroless Ni-Sn-P. when the reducing agent concentration was 20 g/L, the surface appearance is best in the bivalent tin electroless Ni-Sn-P. The tin content and phosphorus content in the deposit increased with an increase in coordination agent concentration in bath, when the coordination agent concentration was 30 g/L, the surface appearance is best in the four valence tin electroless Ni-Sn-P. when the coordination agent concentration was 40 g/L, the surface appearance is best in the bivalent tin electroless Ni-Sn-P. The tin content in the deposit increased with an increase in tin concentration in the bath, the phosphorus content in the deposit decreased with an increase in tin concentration in the bath, when the in concentration was 5 g/L, the deposition rate is best. The deposition rate increased with an increase in pH value, the four valence tin of electroless Ni-Sn-P, the phosphorus content in the deposit increased with an increase in pH value, the tin content in the deposit decreased at first and then increased.The bivalent tin of electroless Ni-Sn-P, when the pH value is 9-10, the surface morphology is best.When the pH value is 4.5, the surface morphology is best.The phosphorus content and the tin content in the deposit is mutual inhibition. Electroless Ni-Sn-P plating has better corrosion resistance than electroless Ni-P plating.The fifth chapter electroless Ni-Sn-P alloy platings of application in microelectronics were studied and succsessfully applied in leadframe with good weldbility,the the tin content in the deposit is 1-2%,the phosphorus content in the deposit is 11-13%.The sixth chapter discussed the difference of bivalent tin and four valence of electroless Ni-Sn-P depositional mechanism.The seventh chapter discussed that the rare earth elements were introduced into Ni-Sn-P alloy by electroless deposition to obtain Ni-Sn-P-RE composite coatings. The effect of rare earth on the deposition rate, composition of the platings, surface morphology and the corrosion resistance were discussed. The results showed that theNi-Sn-P-Ce coatings have better corrosion resistance than Ni-Sn-P coatings, when the Carbonated cerium concentration is 0.03g/L, the corrosion resistance is best and the tin content in Ni-Sn-P-RE coatings is higher than in Ni-Sn-P coatings, the phosphorus content in Ni-Sn-P-RE coatings is lower than in Ni-Sn-P coatings.The rate of deoposition decreased with the increase of lanthanide oxide and Carbonated cerium concentration in bath. The rate of deoposition increased at first and then decreased with the increase of Neodymium oxide concentration, when Neodymium oxide concentration in bath is 0.03 g/L, the rate of deoposition is fastest. The surface morphology of Ni-Sn-P-RE coating is flater, smoother than Ni-Sn-P coatings and cellular structures tend to disappear.更多还原