DIP-COATING OF MO(SI, AL)(2) ON MO WITH AN AL-SI MELT

The formation of intermetallic compound of Mo(Si, Al)(2) on molybdenum for a protective coating of high temperature oxidation was examined by dip-coating technique using Al-Si liquid which was saturated with Si at the temperature range from 1000K to 1200K. The composition of Mo(Si, Al)(2) phase is fixed at Mo(Si-0.85, Al-0.15)(2). The growth kinetics is governed by the interface reaction between Mo and Mo(Si, Al)(2). The other intermetallic compound is not observed, whose formation is expected from the phase diagram of the Mo-Si-Al system. The Mo(Si, Al)(2) formed on Mo is dense and has an excellent adherence to Mo. The layer of Mo(Si, Al)(2) on Mo-wire cracks perpendicular to Mo-Mo(Si, Al)(2) interface, and forms radially. Mo(Si, Al)(2) forms in layer structure on Mo-plate. The activation energy of formation of Mo(Si, Al)(2) is 180 kJmol(-1).