The positive roles of metallic droplets in deposition of alloy films by cathodic arc plasma deposition

The roles of metallic droplets, which generated from the cathodic are spot holes in the technology of Cathodic Are Plasma Deposition (CAPD), are investigated by SEM, TEM, image analysis apparatus, and electronic probe energy spectrum analysis. The results show that though many papers in recent years are devoted to eliminate them, the metallic droplets, including the macrodroplets, have many important positive roles in the preparation of alloy films: they are the main factor to transfer the original composition of alloy cathodic target to the alloy thick films; they preserve the high deposition rate of CAPD to form the basic characteristics of the microstructure and to affect the pore ratios of the films; they also preserve the high melting point elements in the alloy films, and therefore preserve the corrosion resistance of the alloy in the films. The macrodroplets can be eliminated by raising the substrate temperature properly, which is permitted in some cases, such as depositing alloy films onto middle carbon steel as an anticorrosion system, etc.