Improved coatings by isodynamic compression

Selected platelet-powder mixtures that were fabricated from spin-cast ribbon were deposited using arc plasma spraying at various velocities (from subsonic to supersonic) to form rapidly solidified coatings with mechanical-type bonding on a low alloy steel substrate. After deposition at ambient temperatures these sprayed coatings were then subjected to transformation treatments at two elevated temperatures using hot isodynamic compression (HIC) techniques. Efforts aimed at using transformation to achieve greater densities, higher strength and metallurgically bonded coatings are described for an Ni- Mo-Fe-B alloy. HIC and hot isostatic pressing approaches were compared statistically and the significant experimental variables were characterized using Vickers microhardness or electron metallography (scanning electron metallography, electron diffraction spectroscopy and energy-dispersive X-ray microanalysis).