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为提高20钢的防腐、耐热及抗高温氧化性能,以6%KF+2%ZnCl_2为助镀剂,在其表面形成热浸镀铝镀层,采用扫描电子显微镜(Scanning Electron Microscopy,SEM)、HVS-1000显微硬度计和Nano-2000纳米压痕仪等对该镀层分别进行了表面形貌与组织结构观察、显微硬度与纳米硬度测量及弹性模量测量等。结果表明:该镀层由表层的铝层及次表层的铁铝合金层组成,表面及剖面均无开裂与漏镀现象,镀层与基体之间为冶金结合;随着浸镀时间的延长,铝层厚度变化不明显,而铁铝合金层厚度呈抛物线增长;测得铝层显微硬度为57.6 HV_(0. 03),纳米硬度为2.3 GPa,铁铝合金层的显微硬度为781.5 HV_(0.1),纳米硬度为9.2 GPa;铁铝合金层与20钢基体弹性模量基本相当,其平均值均为223 GPa。
In order to improve the anticorrosion, heat resistance and high temperature oxidation resistance of 20 steel, hot-dip aluminum coating was formed on the surface of the steel with 6% KF + 2% ZnCl 2 as fluxing agent. Scanning Electron Microscopy (SEM) HVS-1000 microhardness tester and Nano-2000 nano indenter, respectively, were observed on the surface morphology and microstructure, microhardness and nanohardness measurement and elastic modulus measurement. The results show that the coating consists of the aluminum layer on the surface and the iron-aluminum alloy layer on the subsurface. There is no cracking and leakage on the surface and in the section, and the metallurgical bond between the coating and the substrate. With the extension of immersion time, the aluminum layer The thickness of the Fe-Al alloy layer increased parabolically; the microhardness of the Al layer was 57.6 HV_ (0.03), the nanohardness was 2.3 GPa, the microhardness of Fe-Al alloy layer was 781.5 HV_ (0.1) ), Nano-hardness of 9.2 GPa; Fe-Al alloy layer and 20 steel base elastic modulus are basically the same, the average is 223 GPa.