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针对大功率柴油发动机排气管的隔热层损伤问题,首先采用热浸镀技术在20钢基体表面制备了铝涂层,然后采用微弧氧化技术对铝涂层进行了氧化处理,形成了复合陶瓷涂层体系,并利用扫描电子显微镜(Scanning Electron Microscopy,SEM)、X射线衍射仪(X-Ray Diffraction,XRD)及DZDR-S导热仪对该涂层体系分别进行了表面形貌与组织结构观察、物相分析和热导率检测。结果表明:从宏观上,涂层表面较平整,无漏镀现象,微观上分布有大量微弧孔,但无微裂纹现象;从剖面来看,复合涂层从表至里分别由氧化铝陶瓷层、铝层和铁铝合金层组成;复合陶瓷层的主要物相组成为Al、α-Al2O3、Al86Fe14和Fe,其导热率可达20.06 W/(m·℃)。
Aiming at the damage of the insulation layer on the exhaust pipe of high-power diesel engine, the aluminum coating was first prepared on the surface of 20 steel by hot-dip coating technology and then the aluminum coating was oxidized by micro-arc oxidation to form composite Ceramic coating system. The surface morphology and microstructure of the coating system were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and DZDR-S thermal conductivity meter respectively. Observation, phase analysis and thermal conductivity testing. The results show that: from the macroscopical view, the coating surface is smooth, no leakage plating phenomenon, a large number of micro-arc pores are distributed microscopically, but no microcrack phenomenon; from the section, the composite coating from the table to the inside of the alumina ceramic Layer, an aluminum layer and an iron-aluminum alloy layer. The main phase composition of the composite ceramic layer is Al, α-Al2O3, Al86Fe14 and Fe, and the thermal conductivity can reach 20.06 W / (m · ° C.).