W-Al2O3 heterogeneous bonding by hot-press sintering: Cr diffusion and mechanical strength

W and Al2O3 heterogeneous materials was bonded by using Cr as transition layer, and the diffusion behavior and resulted mechanical strength was studied. Results show that, Cr can diffuse and form metallurgical bonding with both W and Al2O3, and thus connect the heterogeneous materials together. The higher the sintering temperature and time is, the larger the diffusion distance and bonding strength is. Diffusion of Cr in W is defined as diffusion limited, while that in Al2O3 can be considered as interface controlled. Rate constants are 1.79 × 10−7 m/s−1/2 and 3.59 × 10−9 m/s, and kinetic exponent n can be considered as 0.5 and 1, respectively.