| Tungsten carbide-cobalt coatings are extensively used in aeronautical and automotive applications requiring abrasion and erosion wear resistance. In WC-Co alloys, WC is dispersive and horny phase, while the binder Co supplies the necessary coating toughness.In this paper, the low-power plasma spraying equipment (plasma LE-15) is developed by Dalian Maritime University Prof. Gao Yang. Additive to reduce porosity is used. Microstructure of coatings is evaluated by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and so on, meanwhile, the relation between spraying parameters and microstructure, porosity, hardness and phases of WC-Co coatings of additive copper is explored. Then the forming mechanism of additive copper WC-Co coatings and the effects of copper to reduce porosity are discussed on the basis of the microstructure of coatings, while the change of resistance to wear after adding copper into coatings is tested. The main conclusions are as follows:1. Spraying parameters have significant influence on the quality of coatings. When the power increases, the porosity declines and hardness increases.2. Hardness is influenced by the porosity and the content of WC phase. When porosity declines, and the content of WC phase increases, then hardness of coatings increases.3. The major constituents of coatings are WC, W2C which is product of carbon elimination, and the oxidants of copper. Additive copper has inhibiting impact on carbon elimination of WC-Co coatings.4. Copper has some merits such as low melting point, good surface activity, low liquid viscosity, and good liquidity so on, so pores of coatings is filled up for reduce the porosity. At the same power, microstructure of GP12 coatings is better than YF112 coatings, and the dimension of pores is smaller. 5. After adding copper into YF112 coatings, on the one hand, the friction coefficient declines, on the other hand, the resistance to wear reduces. According to work condition, how to mix is chose.
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