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利用离子辅助热蒸发在45钢基材上制备纯铝防护膜,并对其进行喷丸+化学转化后处理。采用中性盐雾机、电化学工作站、扫描电镜、能谱仪对基体及镀铝试样的结构和性能进行研究。结果表明:45钢上铝膜厚度约12μm,膜层晶粒均匀,大小为1~2μm,膜层基体界面紧密,结合良好,膜基之间存在3μm厚的扩散层,扩散层的存在能显著提高基体的耐腐蚀性能。镀铝试样自腐蚀电流比基体低两个数量级,达到1.46×10-6A·cm-2,经盐雾试验1800 h,铝膜部分剥落,没有出现红锈。经过后处理(喷丸+化学转化)镀铝试样,膜层表层致密度提高,并生成一层耐腐蚀转化膜,耐蚀性能得到进一步提高,自腐蚀电流比基体低3个数量级达,达到2.3×10-7A·cm-2,经盐雾试验1800 h后,膜层较完整,没有出现腐蚀严重部位。
The pure aluminum protective film was prepared on the 45 steel substrate by ion-assisted thermal evaporation, and was shot-peening and chemical conversion treatment. The structure and performance of the substrate and the aluminized samples were studied by neutral salt spray machine, electrochemical workstation, scanning electron microscope and energy dispersive spectrometer. The results show that the thickness of the aluminum film on the steel 45 is about 12μm, the grain size of the film is uniform and the size is 1 ~ 2μm. The interface of the film substrate is close and well bonded with 3μm thick diffusion layer. Improve the corrosion resistance of the matrix. The self-corrosion current of the aluminized samples was two orders of magnitude lower than that of the matrix, reaching 1.46 × 10-6A · cm-2. After the salt spray test for 1800 h, the aluminum film partially peeled off and no red rust appeared. After the post-treatment (shot peening + chemical conversion) aluminum samples, the film surface layer density increased, and generate a layer of corrosion-resistant conversion coating, corrosion resistance has been further improved, the corrosion current than the substrate three orders of magnitude lower, 2.3 × 10-7A · cm-2. After salt spray test for 1800 h, the film was relatively intact and no serious sites of corrosion appeared.