Thin-film reactions of Al with Co, Cr, Mo, Ta, Ti, and W

The thin-film interactions of Al with refractory metals (Co, Cr, Mo, Ta, Ti, and W) have been investigated. The composition and thickness of the reacted aluminide layers were determined by Rutherford backscattering and phase identification was made by x-ray diffraction. Scanning electron microscopy was used to examine the lateral uniformity. The initial aluminide phases to grow are the Al-rich phases: Co₂Al₉, Cr₂Al₁₃, MoAl₁₂, TaAl₃, TiAl₃, and WAI₁₂. These are the most Al-rich phases on the phase diagrams. The reaction temperatures varied between 350 and 525 °C.