pH值对碳化硅粉体表面镀镍的影响

The Effect of pH on the Electroless Ni Plating on the SiC Powder

对碳化硅表面进行化学镀镍,研究了镀液的pH值对镀速、镀层组织及形貌的影响。结果表明:镀液pH值低于8.5时,无反应发生,粉体未镀上镍;pH值为10～11时,粉体的增重接近理论值,XRD图谱中的镍衍射峰较强,镀层完全覆盖基体;pH值高于11时,随着pH值的升高,气体生成越发明显,反应速度明显加快,镀液由深蓝色变为无色的时间明显缩短。在pH值10～11范围内对粉体进行二次化学镀,镀层厚度明显增大且显得凸凹不平,镀层中的镍颗粒大小不均匀。

The surface of SiC was plating mental of Ni, and the effect of pH of plating bath on plating speed, phase composition and microstructure was investigated. The results show that the SiC powders have no plating mental of Ni and no reaction can occur when the pH below 8.5. When the pH value is between 10 and 11, the weight gain of powders close to the theoretical value, the Ni peaks in X-ray diffraction patterns of powders is relatively strong and the substrate is covered of Ni plating completely. When the pH value is above 11, the gas production is becoming more pronounced and the reaction speed accelerates significantly with the increased of the pH value, the time of the plating bath changed from dark blue to colorless is obviously shortened. The double-plating is be carry out when the pH value is between 10 and 11, the plating becomes more thickness and has a uneven surfaces, the sizes of Ni particle are not uniform.