Temperature dependence mechanism of high-temperature oxidation of transition metal silicide MoSi2

Yang Huang; Yuhang Zhang; Yusong Wu; Zhikang Yang; Na Wang; Tairan Fu

doi:10.1088/1361-648X/ad4b82

Temperature dependence mechanism of high-temperature oxidation of transition metal silicide MoSi₂

J Phys Condens Matter. 2024 May 28;36(34). doi: 10.1088/1361-648X/ad4b82.

Authors

Yang Huang^{1

2}, Yuhang Zhang^{1

2}, Yusong Wu^{1

2}, Zhikang Yang^{1

2}, Na Wang³, Tairan Fu^{1

2}

Affiliations

¹ Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Beijing Key Laboratory of CO2 Utilization and Reduction Technology, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, People's Republic of China.
² National Key Laboratory of Ramjet, Tsinghua University, Beijing, People's Republic of China.
³ Aerospace Research Institute of Materials & Processing Technology, China Academy of Launch Vehicle Technology, Beijing 100076, People's Republic of China.

PMID: 38744297
DOI: 10.1088/1361-648X/ad4b82

Abstract

Transition metal silicides represented by MoSi₂have excellent oxidation resistance and are widely used as high-temperature anti-oxidation coatings in hot end components of power equipment. However, the mechanism of temperature-dependent growth of MoSi₂oxidation products has not been revealed. Therefore, this study investigated the formation characteristics of oxide film and silicide-poor compound on MoSi₂at temperatures of 1000 °C-1550 °C through high-temperature oxidation experiments, combined with microscopic Raman spectroscopy, scanning electron microscope, and x-ray diffraction (XRD) characterizations. The result showed that MoSi₂underwent high-temperature selective oxidation reactions at 1000 °C-1200 °C, forming MoO₂and SiO₂oxide film on the substrate. As the oxidation temperature increased to 1550 °C, after 100 h of oxidation, along with the disappearance of MoO₂and the phase transformation of SiO₂, a continuous Mo₅Si₃layer with a thickness of approximately 47μm was formed at the SiO₂-MoSi₂interface. Thermodynamics and kinetic calculations further revealed the mechanism of temperature-dependent growth of oxidation products (MoO₂and Mo₅Si₃) during high-temperature oxidation process of MoSi₂. As the temperature increased, the diffusion flux ratio of O and Si decreased, leading to a decrease in oxygen concentration at the interface and promoting the growth of the Mo₅Si₃layer. Its thickness is an important indicator for evaluating the oxidation resistance of MoSi₂coatings during service. This study provides experimental and mechanistic insights into the temperature-dependent growth behavior of Mo₅Si₃during the high-temperature oxidation of MoSi₂coating, and provides guidance for predicting the service life and improving the oxidation resistance of silicide coatings.

Keywords: MoSi2; high-temperature oxidation; oxidation-resistant coating; temperature dependence mechanism; transition metal silicide.