Ternary transition metal nitrides are commonly used as protective coatings on cutting tools, owing to their excellent mechanical and wear properties. While AlTiN is a very well-studied material, little is known about AlZrN, in part due to the large miscibility gap in the phase diagram of AlN-ZrN.
In this study AlZrN thin films were prepared using chemical vapor deposition. By the reaction of metallic aluminium and zirconium with HCl gas under elevated temperature, AlCl3 and ZrCl4 were produced in situ and subsequently transported into a heated coating reactor with a carrier gas. Due to the high temperatures and the separately introduced mixture of NH3 and N2, AlZrN coatings were deposited.
By varying the experimental conditions, such as the ratio between ZrCl4 and AlCl3, the NH3 gas flow and the deposition temperature, we studied the influence of these parameters on the coating thickness and morphology as well as the microstructure. Furthermore, the effects of various annealing temperatures on the AlZrN coatings were investigated and related to structural changes. Ultimately, the generated samples were characterized by scanning electron microscopy, energy dispersive x-ray spectroscopy and x-ray diffraction.
Several AlZrN coatings with good adhesion on WC-Co substrates could be produced. Microstructural characterizations by TEM and wear tests are in progress.