摘要
利用5 kW横流连续CO2激光器,采用粉末预置法在Q235钢表面进行了激光熔覆铁基B4C陶瓷涂层的试验研究。通过试验,优化了工艺参数,深入分析了熔覆层的显微组织及相组成,测试了熔覆层显微硬度、耐磨损及耐腐蚀性能。结果表明,铁基B4 C陶瓷复合涂层与基体达到良好的冶金结合,熔覆层组织主要是由短小柱状枝晶与细小的等轴晶组成,其组成相为α-Fe、Fe3 C、Fe3(B,C)、Fe2 B、CrB、Cr23 C6等化合物,熔覆层中还发现未熔的B4 C颗粒。与基体相比,熔覆层显微硬度显著提高,最高可达到1372 HV0.2,约为基体188 HV0.2的7倍;磨损实验表明,熔覆层与基体表面都出现了磨粒磨损特征的犁沟,熔覆层表面磨损的犁沟比基体浅且细密,熔覆层的耐磨性能显著提高。电化学测试结果也表明,熔覆层的耐腐蚀性能也得到了提高。
Composite coating of Fe-based alloy and B4C ceramics on surface of Q235 steel substrate was prepared by laser cladding technology using a 5 kW continuous wave CO2 laser.The process parameters were optimized based on experiments.Microstructure,phases and properties of the coating were investigated by means of OM,SEM and XRD and micro-hardness measurement,wear and corrosion tests.The results show that a good metallurgical bonding of the coating to substrate is observed.The microstructure of the composite coating consists of short columnar dendrites and fine equiaxed grains.The phases of α-Fe,Fe3 C,Fe3（B,C）,Fe2 B,CrB,Cr23 C6 and B4 C are detected in the coating.Microhardness of the coating reaches 1372 HV0.2,which is much higher than that of the substrate.The wear resistance of the sample with composite coating is considerably improved as compared to the as-received substrate specimen.The electrochemical test results show that the corrosion resistance of the composite coating layer in 3.5% NaCl solution is significantly higher than the base metal.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2011年第3期134-138,共5页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金资助项目(50675148)
山西省自然科学基金资助项目(2008011044)
关键词
激光熔覆
铁基B4C复合陶瓷涂层
显微组织
耐磨损性能
耐腐蚀性能
laser cladding
Fe-based alloy and B4C composite coating
microstructure
wear resistance
corrosion resistance
