沉积气氛对电火花沉积Mo2FeB2基金属陶瓷涂层组织与性能的影响

Influence of deposition atmosphere on structure and properties of Mo2FeB2-based cermet coatings produced by electro-spark deposition

摘要:

采用电火花沉积分别在空气和氩气中制备了Mo₂FeB₂基金属陶瓷涂层,通过扫描电镜(SEM)、X射线衍射(XRD)、显微硬度计和摩擦磨损试验机研究了沉积气氛对涂层形貌、相组成、硬度和摩擦磨损性能的影响。结果表明,两种气氛中沉积所得涂层的组织结构都致密,涂层与基体间无分层,呈冶金结合的特征,但空气中沉积涂层的表面较粗糙,并发生了严重的氧化,涂层均匀性也较差。它们都主要由非晶相和马氏体相组成,但氩气中沉积的涂层含有更多的非晶相。氩气和空气中沉积涂层的最大显微硬度分别为1286.2HV_0.05和1012.9HV_0.05,相差273.3,前者涂层两小时的磨损量几乎仅为后者涂层的1/7,表现出更好的耐磨性。两种涂层的主要磨损机制都是疲劳磨损和磨粒磨损,但氩气中沉积涂层以疲劳磨损为主,空气中沉积涂层则以磨粒磨损为主。

Abstract:

Electro-spark deposition process was used to prepare the Mo₂FeB₂-based cermet coatings in Ar and air, respectively. Influence of deposition atmosphere on morphology, phase constitute, microhardness and friction and wear performance of the coatings were investigated by SEM, XRD, Vickers microhardness tester and tribometer. The results show that the coatings produced in Ar and in air are dense, metallurgical fusion with the substrate, and no delamination can be observed between the coating and the substrate. However, the coating prepared in air was oxidized severely, and has a more rough surface and non-uniform thickness. They are composed of amorphous phase and martensitic phase while more amorphous phase is involved in the coating produced in Ar. The peak microhardness of the coatings produced in Ar and air are 1286.2HV_0.05 and 1012.9HV_0.05, respectively. The coating prepared in Ar is of better wear resistance, its wear mass is about 1/7 that of the coating produced in air. The abrasion mechanism of the coatings is fatigue wear and abrasive wear, and the coating produced in air is mainly fatigue wear, whereas the coating prepared in air is primarily abrasive wear.