烧结钕铁硼磁体表面CeO2/硅烷复合涂层的制备及其耐蚀性能

采用浸涂方式在烧结钕铁硼磁体表面制备CeO2/硅烷复合涂层,研究了硅烷水溶液中纳米CeO2颗粒掺杂量对复合涂层性能的影响,通过扫描电镜、能谱分析仪、动电位极化曲线及中性盐雾试验对所制备的CeO2/硅烷复合涂层的形貌、元素分布以及耐腐蚀性能进行分析。结果表明:纳米CeO2颗粒的添加增强了涂层的硬度,提高了硅烷涂层的屏蔽性能,延长了腐蚀溶液渗入硅烷涂层的腐蚀通道,复合涂层耐中性盐雾试验能力可达24 h。但由于纳米颗粒只是机械的镶嵌到复合涂层中,不会改变硅烷涂层在固化过程中醇基之间脱水缩合反应的本质,在NaCl溶液中,复合涂层依然会形成高低不同的交联密度区,CeO2/硅烷复合涂层失效的主要原因依然是在交联密度低的区域首先水解溶解导致的。

Synthesis and corrosion resistance of CeO2/silane composite coatings on surface of sintered NdFeB magnet

CeO2/silane composite coatings were prepared on the surface of sintered NDFeB magnet by dipping method. The effect of nano-CeO2 particle doping content on the properties of the composite coatings was studied. The morphology, element distribution and corrosion resistance of the CeO2/silicone composite coatings were analyzed by means of scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), potentiodynamic polarization curve and neutral salt spray test. The results show that the addition of nano-CeO2 particles enhances the hardness of the coating, improves the shielding performance of the silane coating, prolongs the corrosion channel through which the corrosion solution seeps into the silane coating, and the resistance to neutral salt spray test of the composite coating can reach 24 h. However, because the nanoparticles are only mechanically embedded in the composite coating, it will not change the nature of dehydration and condensation between alcohol groups in the curing process of silane coating. Therefore in NaCl solution, the composite coating will still form different cross-linking density regions, and the main reason for the failure of the CeO2/silane composite coating is still caused by hydrolysis and dissolution in the region with low cross-linking density.