摘要
目的提高NiAl复合涂层的硬度,扩大它作为涂层材料在矿山机械和石油化工领域的应用范围。方法TiC、TiB_(2)金属陶瓷颗粒具有较高的熔点、硬度、弹性模量及较好的化学稳定性,是一种优良的高温结构材料。采用等离子熔覆技术在Q235低碳钢表面制备NiAl金属间化合物涂层和TiC-TiB_(2)强化NiAl复合涂层,研究涂层的微观组织结构、金属粉末反应热力学、TiC-TiB_(2)强化相的形成机理和涂层的摩擦行为。结果涂层组织紧密、均匀,涂层与基体具有良好的冶金结合。NiAl涂层主要由NiAl、γ-(Fe,Ni)固溶体组成。复合涂层由NiAl、Ni_(3)Al、γ-(Fe,Ni)、TiC和TiB_(2)增强相组成。TiC相呈小块状,TiB_(2)相呈短棒状。粉末反应的热力学计算进一步证明了强化相TiC、TiB_(2)的形成。强化相的形成机理与原子扩散沉淀和晶体结构有关。与NiAl涂层相比,复合涂层的平均硬度从416HV提高到525HV,摩擦因数和磨损失重(质量损失)从0.68、0.376 g分别降至0.54、0.192 g。NiAl涂层磨损表面出现较多大且深的犁坑,NiAl复合涂层磨损表面较为平滑,只有少量浅犁沟。结论TiC和TiB_(2)主要通过溶解、扩散和沉淀析出方式形成。NiAl复合涂层具有高硬度、低摩擦因数和较少的磨损失重,具有优异的耐磨性能。在基体中弥散分布的小块状TiC颗粒和组织稳定性高的强化相有利于提高NiAl复合涂层的硬度和磨损性能。NiAl涂层的磨损机理主要为黏着磨损,复合涂层的磨损类型以磨粒磨损为主。
NiAl intermetallic compound has been widely used as a high temperature or coating material owing to its high ratio-strength and ratio-stiffness,good thermal conductivity and electric conductivity,excellent thermal stability and corrosion resistance.However,the hardness of NiAl compound is low,which results in inferior wear performance.Its application as a coating material is restricted.NiAl intermetallic coatings and TiC-TiB_(2)/NiAl composite coatings were fabricated via the plasma cladding technology in the surface of Q235 low carbon steel.Microstructure characteristics,reaction thermodynamics,the formation mechanism of TiC-TiB_(2)ceramic reinforcement and tribological behavior of the coatings were discussed.The Q235 steel low carbon was used as substrate materials with the size of 100 mm×50 mm×5 mm in this experiment.Nickel powder,aluminum powder,titanium powder and boron carbide powder were used as raw materials of coatings.The matrix was Ni and Al with the atomic ratio of 1∶1.The TiC and TiB_(2)phases were fabricated by the reactions of 3Ti+B4C→TiC+2TiB_(2).The mass percent of TiC-TiB_(2)reinforcements was 20%in composite coatings.The powders were mixed by ball mill.Then they were blended with the sodium silica as binder and pressed on the surface of Q235 low carbon steel by tablet pressing machine.Coatings were prepared by DGR-5 plasma equipment.The microstructure of the coatings was observed by Axio Lab.Al optical microscope and high resolution scanning electron microscopy(HRSEM).The composition of samples was analyzed by JXA-8230 electron probe microprobe analysis(EPMA).The phase was identified by D/Max2500PC X-ray diffraction(XRD).Vickers microhardness was tested with a load of 0.98 N and 15 s of dwelling time in an FM-700/SVDM4R Automatic mico hardness tester.A sliding wear experiment of the sample was carried out with an M-2000 wear test machine.The friction coefficient of the coating was tested with a CETR-UMT-3 multifunctional testing machine.The coating was compact and uniform in addition to n
作者
夏鹏成
占庆威
谢鲲
曹梅青
岳丽杰
孙晓华
董俊伟
XIA Pengcheng;ZHAN Qingwei;XIE Kun;CAO Meiqing;YUE Lijie;SUN Xiaohua;DONG Junwei(School of Material Science and Engineering,Shandong University of Science and Technology,Shandong Qingdao 266590,China;Qingdao Keruis Refrigeration Technology Co.,Ltd.,Shandong Qingdao 266510,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2024年第17期83-93,共11页
Surface Technology
基金
山东省自然科学基金(ZR2020ME015)。
关键词
NiAl复合涂层
热力学计算
强化相
硬度
磨损性能
NiAl composite coating
thermodynamic calculation
reinforcements
hardness
wear performance
