Abstract：The study involves in-situ synthesis of CrFeAlTi composite coating using laser micro-melting 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 Al2O3-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, scanning 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 resistance. 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.
 詹文龙,徐瑚珊.未来先进核裂变能-ADS嬗变系统[J].中国科学院院刊,2012,27(3):375-381. ZHAN W L,XU H S.Advanced fission energy program-ADS transmutation system[J].Bulletin of Chinese Academy of Sciences,2012,27(3):375-381.
 赵志祥,夏海鸿,史永谦,等.加速器驱动次临界嬗变系统(ADS)研究进展[J].中国核科学技术进展报告,2009,1:1-8. ZHAO Z X,XIA H H,SHI Y Q, et al.Research progress for accelerator driven sub-critical transmutation system(ADS)[J].Progress Report on China Nuclear Science and Technology,2009,1:1-8.
 KURATA Y J,YOKOTA H,SUZUKI T.Development of aluminum-alloy coating on type 316SS for nuclear systems using liquid lead-bismuth[J].Journal of Nuclear Materials,2012,424:237-246.
 SERRE I P,DIOP I,DAVID N,et al.Mechanical behavior of coated T91 steel in contact with lead-bismuth liquid alloy at 300℃[J].Surface and Coatings Technology,2011,205:4521-4527.
 栗卓新,祝弘滨,李辉,等.热喷涂金属陶瓷复合涂层研究进展[J].材料工程,2012,(5):93-98. LI Z X,ZHU H B,LI H,et al.Progress of thermal spray cermet coatings[J].Journal of Materials Engineering,2012,(5):93-98.
 王东生,田宗军,陈志勇,等.TiAl合金表面激光重熔等离子喷涂MCrAlY涂层研究[J].材料工程,2009,(7):72-78. WANG D S,TIAN Z J,CHEN Z Y,et al.Study on laser remelting MCrAlY coatings prepared by plasma spraying on TiAl alloy surface[J].Journal of Materials Engineering,2009,(7):72-78.
 祝弘滨,李辉,栗卓新.热喷涂TiB2-Ni复合涂层组织结构和力学性能[J].焊接学报,2014,35(11):43-47. ZHU H B,LI H,LI Z X.Microstructure and mechanical properties of TiB2-Ni composite coating[J].Transactions of the China Welding Institution,2014,35(11):43-47.
 林英华,雷永平,符寒光,等.激光原位制备硼化钛与镍钛合金增强钛基复合涂层[J].金属学报,2014,50(12):1513-1519. LIN Y H,LEI Y P,FU H G,et al.Laser in situ synthesized titanium diboride and nitinol reinforce titanium matrix composite coatings[J].Acta Metallurgica Sinica,2014,50(12):1513-1519.
 张晓伟,刘洪喜,蒋业华,等.激光原位合成TiN/Ti3Al基复合涂层[J].金属学报,2011,47(8):1086-1093. ZHANG X W,LIU H X,JIANG Y H,et al.Laser in situ synthesized TiN/Ti3Al composite coatings[J].Acta Metallurgica Sinica,2011,47(8):1086-1093.
 SHRAVANA K,NANA A,SOUNDARAPANDIAN S,et al.Laser in-situ synthesis of TiB2-Al composite coating for improved wear performance[J].Surface and Coatings Technology,2013,236:200-206.
 高雪松.基于激光熔覆技术制备高结合强度陶瓷涂层的基础研究[D].南京:南京航空航天大学,2010. GAO X S.The basic research on high bonding strength of ceramic coatings fabricated by laser cladding[D].Nanjing:Nanjing University of Aeronautics and Astronautics,2010.
 张来启,张少杰,曾红杰,等.喷砂预处理对HVOF喷涂TiAl-Nb/NiCrAl涂层结合强度的影响[J].材料热处理学报,2011,32(12):105-109. ZHANG L Q,ZHANG S J,ZENG H J,et al.Effect of grit blasting pre-treatment on bond strength of TiAl-Nb/NiCrAl coatings sprayed by high velocity oxyfuel[J].Transactions of Materials and Heat Treatment,2011,32(12):105-109.
 张曼莉,郑文权,邱长军,等.激光原位制备Cr-Fe-Al-Ti复合涂层[J].金属热处理,2015,40(3):19-22. ZHANG M L,ZHENG W Q,QIU C J, et al.Laser in situ synthesized Cr-Fe-Al-Ti composite coating[J].Heat Treatment of Metals,2015,40(3):19-22.
 钱建刚,张家祥,李淑青,等.镁合金表面等离子喷涂Al涂层及激光重熔研究[J].稀有金属材料与工程,2012,41(2):360-363. QIAN J G,ZHANG J X,LI S Q,et al.Study of plasma-sprayed Al coating on Mg alloy and laser-remelting[J].Rare Metal Materials and Engineering,2012,41(2):360-363.
 王淑兰.物理化学[M].北京:冶金工业出版社,2007:274-278. WANG S L.Physical chemistry[M].Beijing:Metallurgical Industry Press,2007:274-278.