化学镀镍-磷-碳-氧体系的热力学与宏观动力学

Thermodynamics and Kinetics of Ni-P-C-O System for Electroless Plating

采用TU-1900型紫外-可见分光光度计和高效液相色谱仪研究了化学镀Ni-P-C-O基础镀液中镍离子与1,4-丁炔二醇(BOZ)浓度的变化,得到了化学镀Ni-P-C-O合金的热力学函数ΔGTφ,ΔH,ΔS及反应动力学规律,探讨了镍离子与BOZ在施镀过程中的作用机理.结果表明,镀液中BOZ浓度的变化是准一级反应,镍离子的浓度变化与BOZ的浓度有关,属多级反应,其反应速率方程为dC/dt=-8.585×10-4+1.188×10-4t-4.62×10-6t2+5.8×10-8t3-2.3×10-11t4,反应体系的活化能Ea随温度的升高而减少,随BOZ浓度的变化而变化:当BOZ浓度在64～123mg/L时,Ea线性减少;在123～240mg/L时Ea线性增加.ΔST随温度的升高而增加,当温度达到80℃时ΔST值最大,反应速度最大;当温度超过80℃,BOZ浓度大于160mg/L时,ΔST的值逐渐减少,反应速度降低.

Changes of nickel ion and butynediols （BOZ） concentration in electroless plating Ni-P-C-O solution were determined by UV-Vis spectrophotometry with high performance liquid chromatography. Thermodynamic functions, such as △GTФ, △H and △S, and kinetic parameters of the Ni-P-C-O alloy chemical plating process were obtained. The reaction mechanism between nickel ion and butynediols in the electroless plating process was analyzed. The results show that the change of BOZ concentration is a quasi first-order reaction, the change of the nickel ion concentration is related to the BOZ density, and this change belongs to a higher order reaction. The reaction rate equation was determined as dC/dt=-8.585×10^-4＋1.188×10^-4t-4.62×10^-6t^2＋5.8×10^-8t^3-2.3×10^-11t^4. The activation energy of this process decreases as temperature increases, and it decreases with the BOZ concentration as 64-123 mg/L, it increases with the BOZ concentration as 123-240 mg/L. The △Sr value is positively correlated to temperature, when the temperature is 80 ℃, the reaction rate and △Sr value are the largest; while when the temperature is above 80 ℃ and BOZ concentration is over 160 mg/L, △Sr value and the reaction rate decrease gradually.