【作者】 王伟；

【导师】 马壮；

【作者基本信息】 辽宁工程技术大学 ， 材料加工工程， 2011， 硕士

【摘要】 本研究分别以Mo-FeB-Fe、Mo-FeB-Fe-Al、Mo-FeB-Fe-TiB₂为反应体系,经聚乙烯醇缩丁醛的乙醇溶液造粒制备喷涂喂料,采用反应火焰喷涂和等离子喷涂技术在Q235钢表面制备了三元硼化物系金属陶瓷涂层,并将涂层于1000℃热处理5h。采用SEM、激光粒度仪、XRD、DSC等测试技术研究了反应体系粉体和涂层的微观形貌、物相组成和反应机理,并对涂层的结合强度、致密性、抗热震性能、耐磨损性和耐腐蚀性进行研究。结果表明:以Mo、FeB合金和Fe粉为原料,采用固相反应烧结破碎法制备喷涂喂料,制备的Mo₂FeB₂金属陶瓷涂层。球磨15h后粉体中有Fe2B生成,900℃烧结后破碎的喷涂粉末有部分三元硼化物（Mo₂FeB₂）生成;涂层由占主体的Mo₂FeB₂和α-Fe相和少量Fe2O₃、FeO相及气孔组成。在涂层和基体的结合面处,存在由高硬度涂层到低硬度钢基体的过渡区;涂层的孔隙率为23%,抗热震次数可以达到38次_;耐磨粒磨损和粘着磨损的能力分别比基体提高了5.28倍和5.16倍;在5wt.%H₂SO4溶液中的耐蚀性比基体提高了4.89倍,涂层经过1000℃真空扩散热处理5h之后,具有更加优异的力学性能。以Mo、FeB合金、Fe和Al粉末为原料,制备的Mo₂FeB₂/Fe3Al金属陶瓷涂层是由硬质相Mo₂FeB₂、Fe₃Al和Fe基粘结相及氧化物Al₂O₃、B₂O₃、MoO₃等组成。涂层的孔隙率为19%,抗热震次数为43次,耐磨粒磨损和粘着磨损能力分别比基体提高了3.04倍和4.24倍,在5wt.%H₂SO₄溶液中的耐蚀性比基体提高了3.02倍;涂层经过1000℃真空热处理5h之后具有更加优异的力学性能。以Mo、Fe、Fe-B合金和TiB₂粉为主要原料,通过聚乙烯醇缩丁醛造粒制备喷涂喂料,制备的Mo₂FeB₂/TiB₂复合陶瓷涂层,是由Mo₂FeB₂和TiB₂硬质相,Fe基粘结相和TiO₂、B₂O₃与Fe的氧化物组成;涂层的抗热震次数最高达到50次,在不同载荷、不同磨损时间下和不同的腐蚀溶液下,等离子喷涂技术制备的涂层具有比反应热喷涂涂层更好的耐磨损性和耐腐蚀性。更多还原

【Abstract】 In this thesis, ternary boride cermets coatings were prepared by Reactive Flame Sprayed （RFS） on Q235 steel substrate using Mo-FeB-Fe, Mo-FeB-Fe-Al and Mo-FeB-Fe-TiB₂ as reaction system. The sprayed-powders were synthesized by sinter-crushing method at 900℃and polyvinyl butyral （PVB） granulation. Phases, particle size distribution, microstructure, and reaction mechanism of the sprayed-powders were investigated by X-ray diffraction （XRD）, laser scattering particle analyzer, scanning electrical microscopy （SEM）/energy dispersive spectrum （EDS） and differential scanning calorimetry （DSC）. The bonding strength between the substrate and the ceramic coating, micro-hardness, thermal shock resistance, porosity, corrosion resistance and wear resistance were characterized with the relevant lab testing equipment.The result indicates that the Mo₂FeB₂ cermets coatings were synthesized by sinter-crushing method using Mo powder, Fe-B alloy powder, and Fe powder as raw materials. Fe2B appeared after milling for 15 h in the powder, ternary boride （Mo₂FeB₂） was generated in sinter-crushing powders at 900℃. The coatings are composed of the major phases Mo₂FeB₂ andα-Fe, a little of Fe2O₃、FeO and some pores. There is a transition from high hardness coating to low hardness substrate, the porosity of the coatings is 23%, the thermal-shock times is 38, the corrosion resistance of coatings is 4.89 times, the abrasive wear resistance and adhesive wear resistance are 5.28 times and 5.16 times than those of the substrate, respectively. The comprehensive properties of Mo₂FeB₂ cermets coatings can be improved further after heat-treatment at 1000℃under vacuum for 5 h.The powders for reactive thermal spraying （RTS） were synthesized by sinter-crushing method at 900℃using Mo, Fe-B alloy, Fe and Al powders as raw materials. Mo₂FeB₂ cermet coatings were prepared by RTS on Q235 steel and heat-treatmented at 1000℃under vacuum for 5 h. Ternary boride （Mo₂FeB₂） and inter-metallic compound （Fe3Al） were generated in sinter-crushing powders at 900℃. The coatings are composed of the Mo₂FeB₂, Fe3Al,α-Fe and some metallic oxides and pores. The porosity of coatings is 19%, the thermal-shock times of the coatings without heat-treatment are 43, the abrasive wear resistance and adhesive wear are 3.04 times and 4.24 times, and the corrosion resistance in 5wt. % H₂SO₄ solution is 4.02 times than those of the substrate, respectively. The comprehensive properties of Mo₂FeB₂ cermet coatings can be improved further after vacuum heat-treatment at 1000℃for 5 h.The TiB₂/Mo₂FeB₂ composite ceramic coatings were synthesized using Mo, Fe-B alloy, Fe and TiB₂ powders as raw materials. The coatings are composed of the major phases Mo₂FeB₂, TiB₂ andα-Fe, a little of Fe₂O₃, FeO, and B₂O₃.The thermal-shock times of RTS-sprayed coatings is 50, the coatings prepared by APS have better wear resistance and corrosion resistance than the coatings prepared by RTS at different load, different time and corrosion media.更多还原