电镀工艺对氨基磺酸盐体系镍镀层内应力的影响

Influence of Electroplating Process on Internal Stress of Nickel Coating in Sulfamate System

目的在氨基磺酸盐电镀体系中,探索出各电镀工艺参数对镀层内应力的影响规律。方法采用一种改良的双阳极-阴极弯曲的办法测试镀层应力。通过X射线衍射实验(XRD)、扫描电子显微镜(SEM)以及KEYENCE数码显微系统,分别分析应力状态下镀层织构、微观畸变以及镀层形貌。结果电流密度越大,镀层的张应力越大,当电流密度达到15 A/dm2时,继续增加电流密度,镀层张应力值不变。电镀时间越长,镀层越厚,张应力值越大,电镀15 min后,镀层应力保持不变。Cl‒浓度越高,镀层的张应力值越大。电流密度对张应力的影响程度比电镀时间显著。X射线衍射全谱拟合表明,磁场的加入会抑制Ni(111)织构的形成,对Ni(200)有择优取向,同时使晶粒的微观畸变变小,磁场强度越强,应力越小。超声空化作用对镀层织构影响不明显,但会降低晶粒的微观畸变,并减小镀层张应力。结论在氨基磺酸镍体系中,电流密度、电镀时间以及Cl‒浓度的增大都会显著增大张应力。磁场和超声的加入在细化晶粒的同时,减小了镀层张应力。

In order to explore the influence of various electroplating process parameters on the internal stress of the coating in the sulfamate electroplating system,a modified double anode-cathode bending method is used to test the coating stress.X-ray diffraction experiment(XRD),scanning electron microscope(SEM)and KEYENCE digital microscope system were used to analyze the coating texture,micro distortion and coating morphology under stress.The results show that the greater the current density,the greater the tensile stress of the coating.When the current density reaches 15 A/dm2,the tensile stress value of the coating remains unchanged with the increase the current density.The longer the electroplating time,the thicker the coating and the greater the tensile stress value.After 15 minutes of electroplating,the coating stress remains unchanged.The higher the Cl‒is,The larger the tensile stress of the coating is.The influence of current density on tensile stress is more significant than the length of plating time.Full spectrum fitting of X-ray diffraction shows that the addition of a magnetic field will inhibit the formation of Ni(111)texture,have a preferential orientation to Ni(200),and at the same time make the microscopic distortion of crystal grains smaller.The stronger the magnetic field,the smaller the stress.Ultrasonic cavitation has no obvious effect on the texture,but it will reduce the microscopic distortion of the crystal grains and reduce the tensile stress of the coating.In conslusion,in the nickel sulfamate system,the increase in current density,electroplating time and Cl‒concentration will significantly increase the tensile stress.The addition of magnetic field and ultrasound reduces the internal stress of the coating while refining the crystal grains.