超音速激光沉积法制备Ni60涂层的显微组织及沉积机理

发布时间：2018-07-14 15:06

【摘要】：超音速激光沉积技术(SLD)是一种将激光辐照与冷喷涂相结合的新型涂层制备工艺,因其结合了激光技术和冷喷涂技术的优势,能够沉积冷喷涂难以沉积或不可能沉积的材料。利用超音速激光沉积技术在中碳钢基材上成功制备了Ni60涂层,并采用扫描电子显微镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)、显微硬度测试等手段对涂层的沉积效率、显微组织成分、结合机理以及显微硬度进行了表征分析。研究结果表明:随着激光加热温度升高,涂层沉积厚度增加,表面球型凹坑逐渐减少;Ni60涂层保持了冷喷涂固态沉积的特征,显微组织结构以及相组成与原始粉末相一致;激光加热导致Ni60沉积层与基体间同时存在机械咬合与冶金结合;涂层的平均显微硬度为867 Hv0.3,比原始粉末提高8%~10%,沉积过程产生了冷作硬化。
[Abstract]:Supersonic laser deposition (SLD) is a new coating preparation technology which combines laser irradiation and cold spraying. Because of the advantages of laser technology and cold spraying technology, SLD can deposit materials which are difficult or impossible to be deposited by cold spraying. Ni60 coatings were successfully prepared on medium carbon steel substrates by supersonic laser deposition. The deposition efficiency and microstructure of the coatings were investigated by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) X-ray diffraction (XRD) and microhardness measurement. The bonding mechanism and microhardness were characterized and analyzed. The results show that with the increase of laser heating temperature, the coating thickness increases, the surface spherical pit decreases gradually and the coating keeps the characteristics of cold sprayed solid state deposition, and the microstructure and phase composition are consistent with the original powder. Laser heating results in mechanical bite and metallurgical bonding between Ni 60 deposit and substrate, and the average microhardness of the coating is 867 Hv 0.3, which is 810% higher than that of the original powder, resulting in cold work hardening during the deposition process.
【作者单位】：浙江工业大学激光加工技术工程研究中心;浙江省高端激光制造装备协同创新中心;
【基金】：浙江省重大科技专项重点工业项目(2012C11001) 浙江省公益技术研究工业项目(2014C31122) 江苏省光子制造科学与技术重点实验室开放基金(GZ201307)
【分类号】：TG174.4

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