Tungsten Carbide / Graphene Self-lubricating and Wear-resistant Coating

Tungsten carbide spraying powder is the basis of preparing tungsten carbide wear-resistant coatings by thermal spraying. To prepare tungsten carbide wear-resistant coatings with self-lubricating properties, self-lubricating additives must be added to tungsten carbide spraying powder. At present, self-lubricating additives mainly include soft metals (Au, Ag, etc.), fluoride (LiF₂, CaF₂, etc.) and so on. Disulfides (MoS₂, WS₂, etc.) and metal oxides (Zr₂O₃, Cr₂O₃, etc.) have been extensively studied as lubricating phases for coatings. 

Recently, some scholars have proposed a preparation method of self-lubricating and wear-resistant tungsten carbide coatings containing modified graphene. The effect is as follows.

The preparation of self-lubricating and wear-resistant coating containing modified graphene tungsten carbide spray powder includes the following steps:

Step 1: A certain amount of modified graphene/nano-tungsten carbide composite was weighed and dispersed by ultrasonic treatment with a certain amount of anhydrous ethanol to obtain the mixed solution of graphene/nano-tungsten carbide composite.

Step 2: Weighing a certain amount of WC/Co sprayed powder, adding the mixed solution of the graphene nano-WC composites obtained in step 1 above, stirring the modified graphene/nano-WC composites with a certain rotating speed at room temperature for a certain time to obtain the mixed solution of the modified graphene/nano-WC composites and WC/Co.

Step 3: Tungsten carbide/cobalt sprayed powders with modified graphene were prepared by vacuum freeze-drying in the mixed solution of modified graphene/nano-tungsten carbide composite and tungsten carbide/cobalt.

Step 4: Tungsten carbide/cobalt self-lubricating wear-resistant coating with modified graphene was prepared by thermal spraying on the surface of the parts after cleaning and sandblasting.

It is found that the graphene in the nano-sheet layer distributes uniformly and dispersively in the coating, and the graphene self-lubricating transfer film is formed on the worn surface continuously during the friction process, thus reducing the friction coefficient of the coating. Moreover, the friction coefficient and wear rate in the friction process of the coating can be greatly reduced, and the working life of the parts can be increased under the worse environment.

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