电火花沉积技术研究现状与展望

电火花沉积技术被广泛地应用于零部件表面涂层的制备与损伤的修复.简要介绍了电火花沉积技术的原理,概括了其进行表面强化与修复的优点.系统地讨论了电火花沉积技术主要工艺参数(电压、电容、比沉积时间和氩气流量)对涂层的沉积效率、形貌、缺陷、组织结构和性能的影响规律,其中热量的输入与释放速率是工艺参数对涂层制备产生影响的关键因素,低能量输入下易获得高性能的涂层,但沉积效率较低.针对电火花沉积技术自身裂纹与孔洞缺陷多、沉积效率低、制备涂层不均匀等问题,介绍了在沉积过程自动化、沉积原理优化、与其他技术复合方面做出的技术改进.其中,通过实现与其他表面强化技术的复合是进一步提高涂层性能的有效方式,将是未来研究的重点内容之一.随后,基于工程实际对高性能涂层的需要,介绍了电火花沉积技术在制备陶瓷、高熵合金、非晶涂层中的应用,电火花沉积技术快热急冷的特点,使其在制备涂层的过程中表现出极佳的细晶、非晶、固溶相形成能力.最后总结了电火花沉积技术存在的问题,并对其未来的发展方向进行了展望.

Research Status and Prospect of Electro-spark Deposition Technology

Electro-spark deposition technology (ESD) is widely used in the preparation of coating and the damage repair for the surface of parts. The principle of ESD was briefly introduced, and its advantages of surface strengthening and repair were summarized. The effects of the main process parameters (voltage, capacitance, specific deposition time and argon flow rate) on the deposition efficiency, morphology, defect, microstructure and properties of the coating were discussed systematically. The input and release rate of heat were the key factors among the process parameters that affected the preparation of the coating. The coating with high performance could be easily obtained under low energy input, but the deposition efficiency was low. Then, aiming at the problems of ESD, such as many cracks and holes, low deposition efficiency and uneven preparation of coating, the technical improvements made in the automation of deposition process, optimization of deposition principle and compounding with other technologies were introduced. The combination with other surface strengthening technologies was an effective way to further improve the performance of the coating, which would be one of the key research contents. Then, based on the needs of engineering practice for high-performance coatings, the application of ESD in the preparation of ceramics, high-entropy alloys and amorphous coatings were introduced. The characteristics of fast heating and rapid cooling of ESD made it show excellent ability to form fine grain, amorphous and solid solution phase in the process of coating preparation. Lastly, the problems of ESD were summarized and the future development of ESD was prospected.