热处理对化学沉积Ni-Fe-P合金性能的影响

采用DSC和XRD研究了化学镀Ni-Fe-P合金的晶化行为和结构.结果表明,镀态合金呈非晶结构, 367.6 ℃下热处理出现亚稳态Ni5P2(P3)和Fe-Ni(Im3m), 499.2 ℃下热处理进一步晶化为稳定的Ni3P(I-4)和FeNi3(Pm3m).采用磁性能实验和在w=3.5％氯化钠溶液浸泡实验以及阳极极化实验研究了热处理对镀层磁性能和耐腐蚀性的影响.结果表明,该镀层在镀态时几乎没有磁性,随着退火温度的升高,磁性能不断提高. 400 ℃以后,镀层的饱和磁化强度和矫顽力随着退火温度升高而急剧上升.浸泡实验和阳极极化实验结果均表明镀态镀层比经热处理后的镀层在w=3.5％氯化钠溶液中具有更好的耐腐蚀性,但是它们的阳极极化行为不同.

The Effect of Heat Treatment on the Properties of Electroless Plating Ni-Fe-P Alloy

The crystallization behavior and the structure of the electroless Ni68.6-Fe9.6-P21.8 deposit were studied by DSC and XRD. The results show that the as-plated deposit consists of amorphous phase, crystallizes into metastable Ni5P2(P3) and Fe-Ni(Im3m) at 367.6 ℃, and transforms into Ni3P(I-4) and FeNi3(Pm3m) at 499.2 ℃. Scanning electron microscopy was performed to observe the surface micromorphology of the as-plated deposit and the deposit heat-treated at 500 ℃. The heat-treated consists of many grains with diameters of 10～30 nm. The microhardness of the deposit increases with the increase of the annealing temperature up to 500 ℃, after which it decreases. The as-plated deposit almost has no magnetism, and its magnetic properties increase with the increase of annealing temperature, showing a rapid increase at above 600 ℃. The saturation magnetization and the coercive force increase greatly with the annealing temperature at above 400 ℃. The corrosion resistances of the as-plated deposit and the deposit heat-treated at 600 ℃ in w=3.5％ NaCl solution (pH 7.0) were investigated by mass loss tests and anodic polarization experiments. The results indicate that the as-plated deposit has a better corrosion resistance than that of the heat-treated deposit in this environment, and their anodic polarization behaviors are different. The above properties of the deposits were discussed from the structure and micromorphology of the deposits.