Abstract: In order to prevent or alleviate the oxidation of tungsten oxidation, a W-Cr-Y self-passivation alloy layer was prepared on the surface of pure tungsten by using double-glow plasma surface metallurgy technology. The microstructure and phase compositions of W-Cr-Y alloy layer were analyzed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The oxidation resistance of the alloy layer was studied under a high temperature atmospheric condition which simulating the cooling failure accident of the nuclear fusion power station. The results show that when the preparation temperature is 800, 900,1000, 1100 ℃, respectively, the W-Cr-Y alloy layer with a thickness of more than 20 μm and composed of W(Cr, Y) solid solution is all successfully formed on the surface of pure tungsten. Moreover, the thickness of the alloy layer prepared at 1000 ℃reaches 35 μm, the surface is smooth and compact, and an excellent defect free metallurgical bonding is obtained between the alloy layer and the tungsten matrix. After oxidation at 1000 ℃ for 10 h, no continuous self-passivation alloy layer is formed on the surface of the W-Cr-Y alloy layer prepared at low temperatures (800 ℃ and 900 ℃), and the oxidation resistance is poor, however,a compact and flat oxide skin is formed on the surface of the alloy layer prepared at high temperatures (1000 ℃ and 1100 ℃). The W-Cr-Y alloy layer prepared at 1000 ℃ has the minimum oxidation mass gain and the optimal antioxidant effect.

Key words: first wall material, self-passivating alloy, double glow plasma surface metallurgy technology, high temperature oxidation resistance