(1. 兰州理工大学 有色金属先进加工与再利用国家重点实验室,兰州 730050;
2. 金川集团机械制造有限公司,金昌 737102)
摘 要: 采用等离子喷焊技术在d100 mm×30 mm 45号钢圆柱基体上制备厚度为5 mm的高铝青铜喷焊层,将制备的喷焊工件在距基体底部分别为32、33和34 mm处进行水平切割,切割后留在基体上的喷焊层厚度分别为2、3和4 mm。在室温条件下,研究喷焊层中元素扩散对其组织、硬度和摩擦磨损性能的影响。结果表明:随分隔层位置从基体到喷焊层纵深方向距离的增加,Fe元素扩散作用减弱;靠近基体的喷焊层中Fe元素含量较多,富Fe 的k相含量多,且呈点状或球状团聚在一起,喷焊层与铁基对摩件的组织相容性增加,在摩擦过程试样易与对摩件黏着;喷焊层硬度虽高,但磨损率较高;靠近喷焊层表面的喷焊层中Fe元素含量最低,k相相貌由粗大树枝状向细小树枝状和粒状组织转变,摩擦因数和磨损率均有所降低, 黏着磨损受到抑制,主要磨损机理为磨粒磨损。
关键字: 等离子喷焊层;元素扩散;k相形貌;摩擦;磨损
(1. State Key Laboratory of Advanced Nonferrous Materials Process and Recycles,
Lanzhou University of Technology, Lanzhou 730050, China;
2. Jinchuan Machinery Manufacturing Co., Ltd., Jinchang 737102, China)
Abstract:High-aluminum bronze coating with a thickness of 5 mm was sprayed by plasma spray welding on 45 medium carbon steel with size of d100 mm×30 mm. The workpieces were cut at zones of 32, 33, and 34 mm from the bottom of the substrate. The thicknesses of coatings on the substrate were 2, 3 and 4 mm, respectively. The effects of element diffusion on the phase structure, microhardness, friction and wear behavior were analyzed at room temperature. The results show that Fe element coming from substrate diffuses into the coating. With increasing the distance from the interface, Fe element diffusion decreases. The volume fraction of Fe-rich k phase is relatively high on the sprayed layer near the substrate. This increases the compatibility of structure between the coating and Fe-based counterpart. The k phase of coating gathers into spots or globules. Such k phase tends to stick the counterpart during friction process, which even causes some particles. Therefore, its wear behavior is the worst despite of the high hardness of coating. However, in the sample near the surface of coating, the bulky dendritic k phases change to small dendritic and granular ones, and thus results in a decrease of adhesive wear, which causes a low friction coefficient and wear rate. The wear mechanism is characterized as abrasive wear.
Key words: plasma spray coating; element diffusion; phase morphology; friction; wear