激光原位合成Al_2O_3-TiO_2复合陶瓷涂层组织结构与性能

先利用火焰喷涂技术在中国低活化马氏体钢表面制备了CrFeAlTi涂层,然后通过激光原位反应技术在火焰喷涂涂层表面原位合成了Al_2O_3-TiO_2复合陶瓷涂层。分别采用体视显微镜、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)、显微硬度计、立式万能摩擦磨损试验机以及静态铅铋腐蚀实验装置等分析测试手段对涂层的形貌、微观组织结构、物相组成、显微硬度、干滑动摩擦磨损性能以及耐液态铅铋合金腐蚀性能等进行了研究。实验结果表明:激光原位合成的Al_2O_3-TiO_2复合陶瓷涂层表面整体平整、光滑、致密,基本没有凹坑、裂纹和孔隙等缺陷,与基体之间形成了良好的冶金结合。涂层内部存在完全结晶区和非结晶区,且界面明显。涂层表面主要物相为Al_2O_3,TiO_2,(Al.948Cr.052)_2O_3,Fe_2TiO_5和FeCr等。涂层截面平均显微硬度约为1864.2HV0.2,比基体CLAM钢提高了约3倍,且沿横截面方向呈平稳过渡的阶梯状分布。与基体CLAM钢相比,涂层具有良好的耐磨性能,其磨损量仅为基体的1/6,并且涂层在液态铅铋中表现出良好的耐腐蚀性能。

Microstructure and Properties of Laser In-situ Synthesized Al2 O3-TiO2 Composite Ceramic Coating

The study involves in-situ synthesis of CrFeAlTi composite coating using laser micro-melt-ing processing .The coating was successfully prepared by laser irradiating CrFeAlTi coating prepared by flame spraying on the China low activation martensitic (CLAM ) steel substrate ,and then Al2 O3-TiO2 composite ceramic coating was synthesized by in-situ reaction on the surface of flame sprayed coating .The coating morphology ,microstructure ,phase composition ,micro-hardness ,dry sliding wear properties and corrosion resistance in liquid PbBi alloy were analyzed by stereomicroscope ,scan-ning electron microscope (SEM ) , transmission electron microscope (TEM ) , X-ray diffraction (XRD) ,micro-sclerometer ,vertical universal friction wear testing machine and static PbBi corrosion test device ,respectively .The test results show that the surface of Al2O3-TiO2 composite ceramic coating is smooth ,and the microstructure of coating is both homogeneous and dense without defects such as crack ,dimple and porosity ,etc .,a good metallurgical bonding between the composite ceramic coating and the substrate ,and the interface is obvious .The phases of the coating surface are mainly composed of Al2O3 ,TiO2 ,(Al .948Cr .052)2O3 ,Fe2TiO5 and FeCr ,etc .The coating shows a high average micro-hardness of approximately 1864 .2HV0 .2 ,which is about three times higher than that of the CLAM steel substrate ,and presents gradient distribution with stable transition from the coating surface to the substrate .Comparing with the substrate ,the coating presents excellent wear resist-ance .The wear mass loss of the coating is just one sixth of that of the substrate .Meanwhile ,the coating exhibits the best corrosion resistance in the liquid PbBi.