双向脉冲电沉积法在钕铁硼永磁体表面制备铁-镍-钴合金

Preparation of iron-nickel-cobalt alloy on Nd-Fe-B permanent magnet by bi-directional pulse electrodeposition

针对稀土永磁体温度稳定性较差,利用双向脉冲电沉积法在钕铁硼永磁体上电沉积Fe-Ni-Co合金。镀液组成和操作条件为:FeSO4.7H2O40g/L,CoSO4.7H2O1g/L,NiSO4.7H2O120g/L,NiCl2.6H2O25g/L,H3BO340g/L,乳酸20mL/L,抗坏血酸20g/L,糖精2g/L,柠檬酸钠80g/L,十二烷基硫酸钠0.01g/L,乙二醇20mL/L,pH=3,温度60～65°C。通过扫描电镜和X射线衍射考察了合金镀层形貌及结构,采用划痕法和中性盐雾试验分别测试了合金镀层的结合力和耐蚀性。实验结果表明,制得的合金镀层表面较均匀致密,结合力好,耐蚀性强。磁性能测试表明该合金镀层有一定的温度补偿作用。

Aiming at the poor temperature stability of rare earth permanent magnet, Fe-Ni-Co alloy was deposited on a Nd-Fe-B permanent magnet by bi-directional pulse electro- plating method. The bath composition and operating conditions are as follows： FeSO4.7H20 40 g/L, COSO4.7H20 1 g/L, NiSO4.7H20 120 g/L, NiC12.6H20 25 g/L, H3BO3 40 g/L, lactic acid 20 mL/L, ascorbic acid 20 g/L, saccharin 2 g/L, sodium citrate 80 g/L, sodium dodecyl sulfate 0.01 g/L, glycol 20 mL/L, temperature 60-65 ℃, and pH 3. The morphology and phase structure of the coating were examined by SEM and X-ray diffraction, and the adhesion strength and corrosion resistance were tested by knife-cutting and salt spray methods. The experimental results show that the deposited Fe-Ni-Co alloy has a uniform and compact surface with good adhesion and corrosion resistance. The magnetism test revealed that the alloy can make a certain temperature compensation for rare earth permanent magnet.