Chromium-based coatings by atmospheric chemical vapor deposition at low temperature from Cr(CO)6

Abstract

Cr-based coatings were grown under atmospheric pressure in different gaseous atmospheres (N2,H2, NH3) from the thermal decomposition of Cr(CO)6 at 300 °C in a cold-wall CVD reactor. Cr(CO)6 is a good candidate as precursor because of its low cost and its high volatility, which permits high flow rates. Original chromium oxycarbide and oxynitride coatings were deposited on steel. These phases were previously obtained by plasma-assisted CVD and low-pressure CVD, i.e., under nonequilibrium conditions. In the present work, the low deposition temperature likely accounts for their formation. We have investigated correlations between the growth conditions and their main chemical, structural and physical features. Preliminary results on the mechanical behavior of these Cr-based coatings are also reported.