激光熔覆原位生成增强相强化铁基涂层性能研究

目的 采用激光熔覆技术在304不锈钢表面制备含有碳铬、硼钛化合物及氧化钛等增强相的铁基熔覆层,并对涂层的微观组织及其性能进行研究分析,以期为以后工业化应用提供理论基础.方法 对钛铁(钛质量分数70%)+硼铁(硼质量分数70%)+石墨(纯度99.9%)复合粉末质量分数分别为5%、10%、20%、30%的4种熔覆层(其余熔覆材料为304不锈钢粉末)进行了实验研究,利用扫描电镜(SEM)、X射线衍射对激光熔覆层的微观组织形貌和增强粒子的成分进行研究分析,用光学显微硬度计对激光熔覆层的显微硬度进行测试,用电化学工作站对熔覆层的耐蚀性能进行测试.结果 熔覆层无明显裂纹、气孔等缺陷,与基材结合良好;加入的石墨与钛铁、硼铁在激光熔覆过程中发生了反应,原位生成了Cr23 C6、Cr3 C2、TiO2、Ti1.8 B50等硬质增强相;随着钛铁、硼铁和石墨所占的质量分数增加,熔覆层中生成的硬质增强相含量增加,熔覆层的显微硬度值也随之得到明显提高,其中质量分数为30%的复合粉末熔覆层硬度是基材的3.6倍;激光熔覆试样较基材的耐腐蚀性也随着复合粉末质量分数的增加而提高,其中质量分数为30%的复合粉末熔覆层的耐蚀性是基材的1.58倍.结论 激光熔覆制备含有碳铬、硼钛化合物及氧化钛等增强相的铁基熔覆层较基材性能有明显提高.

Performance Improvement of Iron Base Coating by Laser Cladding In-situ Generated Reinforced Phase

Objective Laser cladding technology was used to prepare iron base cladding layers containing reinforced phases such as carbon chromium, titanium boron compounds and iron base of titanium oxide on the surface of 304 stainless steel, and the microstructure of the coating and its performance was researched and analyzed, so as to provide theoretical basis for future industrial application. Methods The four kinds of claddings with 5% , 10% , 20% , 30% mass ratios of ilmenite (titanium 70wt% ), iron-boron (boron 70wt% ) and graphite (carbon 99. 9wt% ) composite powder were studied experimentally. The microstructure of laser cladding layers and composition of reinforced particles were analyzed using scanning electron microscope ( SEM) and X-ray diffraction (XRD), the microhardness of the laser cladding layer was tested using optical microscopy hardness tester, and the corrosion resistance of the cladding layer was tested using electricity chemistry workstation. Results The results showed that the cladding layer had no obvious defects such as cracks, porosity, and was well bound with the base material. Reaction occurred in the process of laser cladding among the graphite, ilmenite and boron iron added, and rigid reinforced phases such as Cr23C6,Cr3C2,TiO2,Ti1. 8B50 were in situ generated. With increasing mass fractions of graphite, ilmenite and boron iron, the contents of rigid reinforced phase generated in the cladding layer increased, and the microhardness value of the cladding layer was also obviously improved. The hardness of cladding layer containing 30% of the composite powder was 3. 6 fold as high as that of the base material. The corrosion resistance of the laser cladding specimens was also higher than that of the base material, and it increased with the increasing mass ratio of the composite powder. The corrosion resistance of cladding layer containing 30% of the composite powder was 1. 58 fold as high as that of the base material. Conclusion Iron base cladding layers containing reinforced phases such as carbon chromium, titanium boron compounds and titanium oxide prepared by laser cladding had significantly improved performance than the base material performance.