Chromium nitride and chromium aluminum nitride epitaxial films for growth of alpha-alumina by AC reactive magnetron sputtering.

摘要

Chromium based coatings like CrN and CrAlN have found their way in variety of applications which includes cutting, cold and semi-cold forming of Ni, Ti-alloys, and other non-ferrous alloys of aluminum, copper. They are also used for pressure-die casting of aluminum, corrosion and wear protection of molds, tools, and components in the plastic industry, and for wood machining. CrN and CrAlN coatings are characterized by high hardness, wear and corrosion resistance, and high temperature oxidation resistance.; The aim of this work was to investigate the deposition parameters for producing crystalline CrN, and CrAlN films with good structural, mechanical, and tribological properties. The next step was ex-situ oxidation of the CrN and CrAlN to form a thin layer of chromium oxide, as the epitaxial template for the subsequent growth of crystalline alumina, which was the objective of GOALI proposal funded by National Science Foundation (NSF-DMI 004167). This was done by performing a matrix of experiments using inverted cylindrical magnetron sputtering at three different gas ratios, and target powers. The films were characterized using various tools like Environmental Scanning Electron Microscopy, X-Ray Diffraction, X-Ray Photoemission Spectroscopy, Auger Electron Spectroscopy, Energy Dispersive Analysis, Atomic Force Microscopy, Micro-Hardness measurements, and room temperature and high temperature Pin-on-Disc measurements.