激光熔覆铁基合金涂层的高温氧化性能

High-Temperature Oxidation Properties of Fe-Based Alloy Coating Prepared by Laser Cladding

通过在Fe基合金粉末中添加Cr3C2的方法,在35CrMo钢表面激光熔覆制备抗高温氧化Fe基合金复合涂层。采用扫描电镜(SEM)、能谱分析仪(EDS)、X射线衍射仪(XRD)等分析手段对激光熔覆层600℃氧化100h后的氧化膜形貌及成分进行分析,研究不同Cr3C2含量对抗高温氧化性能的影响。结果表明,激光熔覆Fe基合金涂层组织均匀致密,与基体结合良好,无裂纹、气孔等缺陷。在600℃下,Fe基合金涂层和添加Cr3C2的Fe基合金涂层的抗高温氧化性能均明显优于基体,其累计氧化增重及增重速率远远小于基体。Fe基合金熔覆层600℃氧化后表面形成了FeCr2O4尖晶石氧化物,具有较好的抗氧化能力。由于添加的Cr3C2熔覆过程中发生分解,使熔池中Cr元素含量提高,高温下试样表面形成连续完整的Cr2O3氧化膜,故添加Cr3C2的熔覆层的抗高温氧化性能提高。

Fe-based alloy composite coating is produced by laser cladding Fe-base powder containing CraC2 powder. The morphology and component of the oxide scales of laser cladding coating at 600 ℃ for 100 h are analyzed by means of scanning electron microscope （SEM）, energy dispersive spectrometer （EDS） and X-ray diffraction （XRD）. The results show that the microstructures of the Fe-based alloy composite coatings are uniform and dense without cracks and pores. At 600 ℃ the high-temperature oxidation resistance of the Fe-based composite coatings with Cr3 C2 powder is improved obviously compared with the matrix and the accumulative oxidation mass-gain and oxidation ratio are less than the matrix. At 600 Y; FeCr204 spinel oxide are formed on the surface of the pure Fe-base alloy coating with better high-temperature oxidation resistance. With the addition of Cr3C2 powder, Cr3C2 is decomposed at high temperature and the content of Cr in the molten pool is improved significantly, resulting in the formation of the continuous and complete Cr203 scales, and the improvement of the high-temperature oxidation resistance compared with the coating without Cr3 C2 powder.