Co-W composite oxide coating, connecting material coated with Co-W composite oxide coating and preparation method of Co-W composite oxide coating

The invention discloses a Co-W composite oxide coating. The Co-W composite oxide coating comprises an inner-layer oxide, a middle-layer oxide and an outermost-layer oxide, wherein the inner-layer oxide is a chromium-containing oxide layer, the middle-layer oxide is a CoWO4 layer, and the outermost-layer oxide is a ferrocobalt spinel layer. The connecting material is formed by coating the Co-W composite oxide coating on the surface of ferritic stainless steel. The preparation method comprises the following steps: (1) processing the shape of the ferritic stainless steel, blasting sand and pickling; (2) impact electroplating and electroplating; and (3) carrying out heat treatment and pre-oxidation treatment. The connecting material is excellent in high-temperature oxidation resistance, capable of effectively inhibiting Cr diffusion, good in thermal shock stability and high in high-temperature water vapor corrosion resistance. The preparation method disclosed by the invention has the characteristics of short synt