Mechanical properties and high-temperature behavior of non-reactive synthesized MoSi2 thin films by PVD techniques

Abstract

Molybdenum disilicide belongs to the group of refractory transition metal silicides, known as a highly attractive material withstanding extreme oxidative environments. Due to the formation of a protective silicon-based oxide and its mixed metallic and covalent bonding character, MoSi2 exhibits an exciting combination of outstanding high-temperature oxidation resistance but also suitable mechanical properties. Within our study, we synthesized MoSi2 thin films by direct current and high-power pulsed magnetron sputtering (DCMS & HPPMS) in pure Ar atmospheres. The influence of the deposition parameters (e.g., temperature, bias potential, frequency, or duty cycle) on the phase formation and mechanical properties was investigated systematically. All coatings deposited have been in-depth analyzed concerning their structure-mechanical properties, using a broad set of characterization techniques – i.e., scanning and transmission electron microscopy (SEM & TEM), X-ray diffraction (XRD), and nanoindentation. In addition, the high-temperature behavior and the oxidation kinetics have been studied in detail using a combined differential scanning calorimetry/thermogravimetric system (DSC-TGA). The oxidation resistance was investigated more thoroughly for different temperature regimes up to 1500 °C.