化学镀镍-钴-铁-磷镀层的结构和磁性能

Structure and magnetic performances of Co-Ni-Fe-P alloy plated by electroless deposition

采用H3BO3为缓冲剂、柠檬酸钠为络合剂,在弱碱性体系中化学沉积Ni-Co-Fe-P合金,运用能谱分析仪(EDS)、扫描电镜(SEM)和X射线衍射仪(XRD)研究镀液pH值对合金结构的影响。结果表明,随着镀液pH值增大,镀层中Fe和Co含量呈增加趋势而Ni和P含量趋于减少;镀层表面圆形颗粒呈密堆积,且随着镀液pH值的增加,圆形颗粒的粒径减小;镀态镀层呈非晶态结构。镀层在266.9℃晶化产生Fe-Co(Pm3m)相,在389.6℃生成亚稳相Ni8P3(R3C)和Co3Fe7(Pm3m)相,随后在500℃进一步晶化形成Ni3P(I-4)和Ni(Fm3m)相。随着热处理温度的升高,合金的饱和磁化强度和矫顽力呈增加趋势。

Electroless Ni-Co-Fe-P alloys were deposited from a soft alkaline bath, containing boric acid as a buffer agent and sodium citrate as a complexing agent. The effect of the bath pH value on the coating structure was investigated by energy-dispersive X-ray spectral analysis （EDS）, scanning electron microscope （SEM） and X-ray diffractrometry （XRD）. As a result, with the increase of the bath pH value, the iron and cobalt contents of the deposit increase basically, while the nickel and phosphorus contents decrease. The deposit surface has compact particles, and the particle size increases with the bath pH value. The structure of the deposit is amorphous. The deposit is converted into Fe-Co （Pmam） phase at 266.9 ℃, and transformed into NisP3 （R3c） meta stable phase and Co3Fe7 （Pm3m） phase at 389.6 ℃, and then crystallized into NiaP （I-4） and Ni （Fmam） stable phases at 500 ℃. The saturation magnetization and coercivity of the film increase with increasing the heat treatment temperature.