X-ray diffraction study of effect of deposition conditions on \alpha-\beta phase transition and stress evolution in sputter-deposited W coatings

Pure W and W--Cu--W trilayer coatings were deposited on an Fe substrate by d.c. magnetron sputtering. The \alpha -\beta phase evolution, intragranular stress evolution in sputter-deposited W layer were investigated by x-ray diffraction. They are directly related to the film microstructure, density and adhesion. Therefore, control of the film stress and phase component transition is essential for its applications. The phase component transition from \beta-W to \alpha -W and intragranular stress evolution from tensile to compressive strongly depend on the deposition parameters and can be induced by lowering Ar pressure and rising target power. The compressively stressed films with \alpha -W phase have a dense microstructure and high adhesion to Fe substrate.