Bonding characteristics and chemical inertness of Zr-Si-N coatings with a high Si content in glass molding

Abstract

High-Si-content transition metal nitride coatings, which exhibited an X-ray amorphous phase, were proposed as protective coatings on glass molding dies. In a previous study, the Zr-Si-N coatings with Si contents of 24-30 at.% exhibited the hardness of Si3N4, which was higher than those of the middle-Si-content (19 at.%) coatings. In this study, the bonding characteristics of the constituent elements of Zr-Si-N coatings were evaluated through X-ray photoelectron spectroscopy. Results indicated that the Zr 3d5/2 levels were 179.14-180.22 and 180.75-181.61 eV for the Zr-N bonds in ZrN and Zr3N4 compounds, respectively. Moreover, the percentage of Zr-N bond in the Zr3N4 compound increased with increasing Si content in the Zr-Si-N coatings. The Zr-N bond of Zr3N4 dominated when the Si content was > 24 at.%. Therefore, high Si content can stabilize the Zr-N compound in the M3N4 bonding structure. Furthermore, the thermal stability and chemical inertness of Zr-Si-N coatings were evaluated by conducting thermal cycle annealing at 270 °C and 600 °C in a 15-ppm O2-N2 atmosphere. The results indicated that a Zr22Si29N49/Ti/WC assembly was suitable as a protective coating against SiO2-B2O3-BaO-based glass for 450 thermal cycles.