钕铁硼化学镀防护及在模拟海洋大气环境中的腐蚀行为

Protection of NdFeB by Electroless Plating and Its Corrosion Behavior in Simulated Marine Atmosphere

采用化学镀方法在钕铁硼表面分别制备Ni-P合金镀层、Ni-Mo-P合金镀层、Ni-P/PTFE复合镀层和Ni-Mo-P/PTFE复合镀层,并研究了不同化学镀层在模拟海洋大气环境中的腐蚀行为。结果表明:Ni-P合金镀层、Ni-Mo-P合金镀层、Ni-P/PTFE复合镀层和Ni-Mo-P/PTFE复合镀层都完整覆盖钕铁硼表面,它们的粗糙度差别不大,在模拟海洋大气环境中的腐蚀失重都低于钕铁硼的腐蚀失重,容抗弧半径增大且电荷转移电阻有不同程度的提高。与Ni-P合金镀层和Ni-Mo-P合金镀层相比,Ni-P/PTFE复合镀层和Ni-Mo-P/PTFE复合镀层具有优良的耐腐蚀性能,原因在于PTFE颗粒较均匀的沉积在镀层表面增加一道屏蔽层,也起到阻碍腐蚀介质渗透腐蚀的作用。尤其是Ni-Mo-P/PTFE复合镀层,其表面更致密,PTFE颗粒沉积更均匀,能更有效延缓腐蚀介质与钕铁硼接触,显著提高钕铁硼在模拟海洋大气环境中的耐腐蚀性能。

Ni-P alloy coating,Ni-Mo-P alloy coating,Ni-P/PTFE composite coating and Ni-Mo-P/PT-FE composite coating were prepared on the surface of NdFeB by electroless plating respectively,and the corrosion behavior of different electroless coatings in simulated marine atmosphere was studied.The results showed that Ni-P alloy coating,Ni-Mo-P alloy coating,Ni-P/PTFE composite coating and Ni Mo-P/PTFE composite coating were completely covered the surface of NdFeB,and there was little dif-ference in their roughness.The corrosion weight loss of different electroless coatings in simulated ma-rine atmosphere was lower than that of NdFeB,the radius of capacitive reactance arc was increased and the charge transfer resistance was increased in different degrees.Compared with Ni-P alloy coating and Ni-Mo-P alloy coating,Ni-P/PTFE composite coating and Ni-Mo-P/PTFE composite coating showed excellent corrosion resistance,the reason was that PTFE particles were evenly deposited on surface of the coating to form an additional shielding layer,which could also plays a role in preventing the erosion of corrosive media.Especially for Ni-Mo-P/PTFE composite coating,its surface was denser and PTFE particle deposited more uniform,which could more effectively delay the contact between corrosive me-dium and NdFeB,and then significantly improved the corrosion resistance of NdFeB in the simulated marine atmosphere.