Zirconium aluminum nitride thin films for temperature sensing applications

This study explores the development and characterization of zirconium aluminum nitride (ZrAlN) thin films produced via magnetron sputtering for temperature sensing applications. The sensor film is integrated into a fully nitride multilayer coating and designed to work in harsh environments. The ZrAlN demonstrated stable semiconductor behavior up to 750 °C, making it suitable for high-temperature thermistors, with a β value of approximately 850 K after signal stabilization. Detailed structural characterization confirmed a mixed-phase structure of poorly crystalline cubic ZrN and orthorhombic Zr₃N₄. This structure is believed to be responsible for the high resistivity of 8.0 × 10⁵ µΩ·cm observed in Zr_1-xAl_xN with x = 0.3. The examination of Zr_0.7Al_0.3N integrated into the multilayer coating revealed a columnar morphology with diffuse nanolayers, alternating between aluminum-rich and aluminum-poor zones, caused by the two-fold rotational deposition. The sensor coating was further tested on a cutting tool substrate, with the Zr_0.7Al_0.3N layer exhibiting a sensitivity of 800 K and demonstrating effective temperature measurements up to 400 °C. The Zr_0.7Al_0.3N layer inserted in a nitride-based multilayer coating, combined with Arduino® for signal acquisition, resulted in a measured error of approximately 7 %. The setup presented the potential for integration into manufacturing environments aligned with Industry 4.0.