Diffusion Behavior and Mechanism of Dy with W-Mo-Dy Plasma Alloying

W-Mo alloying layer and W-Mo-Dy alloying layer were prepared on carbon steel surface by using glow plasma alloying technique,the diffusion activation energy of tungsten atoms and molybdenum atoms was calculated by Fick′s Second Law,and two possible diffusion models of rare earth Dy were studied.The results show that under the conditions of ion bombardment and non-balance,vacancy concentration on substrate surface increasing and diffusion activation energy of alloy elements decreasing make the diffusion velocity of Dy increase and promote the diffusion of tungsten and molybdenum atoms.The diffusion model at deffusion preliminary stage is "vacancy exchange diffusion",once the diffusion process is to a certain degree,the diffusion model is "rare earth-vacancy complexes diffusion".