磁控溅射铝膜的微观结构对磁致冷钆腐蚀性能的影响

摘要

研究了表面镀铝和未镀铝的钆的静态和电化学腐蚀试验。结果表明，未镀铝的钆在水作用下表面形成大量裂痕，而多角状的铝膜结构由于点蚀坑的存在比片状铝膜结构的耐腐蚀性能差。片状铝膜由于与基体之间形成有效的物理阻挡，且片状结构致密，延长了阴极保护。因此，制备表面层状铝膜结构是显著提高磁制冷钆表面耐腐蚀性能行的有效方法。%Al coatings with different microstructures were prepared on the surface of Gd using the magnetron sputtering technique to improve its corrosion resistance. The corrosion behaviors for the pure Gd and Gd with Al coating in distilled water were studied using the mass loss and electrochemical performance. As a result, pure Gd without coating shows a certain amount of surface cracks under water flow conditions, whereas the polygonal Al coating decreases the path of the corrosive medium to body due to the existence of eroding pits structure. Compared with the polygonal structure Al coating and pure Gd, the lamellar structure of Al coating exhibits a higher electrochemical protection performance (e.g., a lower corrosion current and higher self-corrosion potential) and no occurrence of pitting corrosion. Due to an effective physical shield, the formation of the lamellar structure protected the inner Gd part from being corroded, and prolonged the duration of cathodic protection.