摘要
利用3 kW高功率半导体激光器,在304钢基体上制备不同含量Ni基Ni包B_4C复合陶瓷涂层,分别用扫描电镜(SEM)、X射线衍射(XRD)、显微硬度计及摩擦磨损试验机对熔覆层的显微组织、物相、硬度及耐磨性进行研究。结果表明:熔覆层主要由γ-Ni固溶体、B_4C、Fe_3B、Ni_4B_3、Cr_5B_3、CrB、Cr_3C_2、Cr_2Ni_3等物相组成;熔覆层底部晶粒以近似垂直于基体界面的细小树枝晶的形态生长的,中部以一定方向柱状晶和树枝晶存在,上部是杂乱无章的等轴枝晶;Ni包B_4C含量为40%时,熔覆层组织均匀致密、晶粒细小,与基体冶金结合,显微硬度最高1261 HV,是基体的5.7倍,耐磨性也相对较好,是基体的12倍。
Nickel-based composite coatings were prepared on 304 stainless steel by laser cladding using Ni and Ni coated B_4C powders with different contents of B_4C. Microstructure,phase composition,hardness and wear resistance of the laser clad coatings were studied by means of scanning electron microscopy( SEM),energy dispersive spectrometer( EDS) analysis,X-ray diffraction( XRD) and friction and wear test. The results show that the laser clad coatings are composed γ-Ni,B_4C,Fe_3B,Ni_4B_3,Cr_5B_3,CrB,Cr_3C_2 and Cr2Ni3. The microstructure of the coatings exhibits a cell structure perpendicular to the interface of the coating and the substrate at the bottom,columnar crystal and dendritic structure growing with a single direction for the central layer,and dendrites with random direction for the upper layer. When the content of Ni coated B_4C is 40%,the microstructure of the clad coating is uniform and compact with metallurgical bonding with the substract,the hardness of the coatings reaches 1261 HV,which is 5. 7 times of that of the substrate and its wear increases by 12 times compared with that of the substrate.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2016年第11期146-151,共6页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(61475117
51261027)
国家自然科学资金委员会与中国民用航空局联合资助项目(U1333121)
天津市应用基础及前沿技术研究计划(12JCQNJC02800)
天津市科技支撑重大专项项目(13ZCZDGX01109)
中国民航大学开放基金项目(2014TJPUJG)
天津市高等学校科技发展基金计划(20120631)
关键词
激光熔覆
Ni包B4C
陶瓷涂层
组织性能
laser cladding
Ni coated B4C
ceramic coating
microstructure and property