活化时间对化学镀Ni-P-Al_2O_3镀层组织及性能的影响

Effect of Activation Time on Microstructure and Properties of Electroless Ni-P-Al_2O_3 Coatings

采用化学镀方法在45#钢基体上制备了Ni-P-Al_2O_3镀层,并研究了活化时间对镀层的组织结构、硬度、摩擦因数及耐蚀性的影响。结果表明:当活化时间由40s延长至120s时,镀层的表面组织都由胞状颗粒组成,组织变化由非均匀致密→均匀致密→不均匀致密。当活化时间为80s时,镀层的组织最均匀致密,由Ni-P-Al_2O_3非晶胞构成,XRD图谱上没出现基体Fe的衍射峰,说明镀层较厚,完全覆盖基体。镀层的硬度、摩擦因数、耐蚀性均随活化时间的延长先增后减,活化时间为80s时制备的镀层硬度最高、摩擦因数最小、耐蚀性最好。

Ni P Al2O3 coating was prepared on 45^# steel substrate by electroless plating, and the effect of activation time on the microstructure, hardness, ffiction coefficient and corrosion resistance of the coatings was studied. Results showed that, when the activation time was increased ftom 40 s to 120 s, the microstructure of the coating was composed of cell like particles, and the change of microstructure was as follows： non uniform dense→uniform dense→ uneven dense. When the activation time was 80 s, the coating was composed of Ni-P- Al2O3 amorphous crystal, its microstructure was homogeneous and compact, and Fe diffraction peak was absent in XRD spectrum, indicating that the coating was thick and the substrate was completely covered by Ni P A1203 coating. The hardness, friction coefficient and corrosion resistance of the coating were increased first and then decreased with the increase of activation time. When the activation time was 80 s, the hardness of the prepared coating was the highest, friction coefficient was the smallest and corrosion resistance was the best.