Mechanochemical synthesis of Cr3C2: investigating the role of pressure and temperature

Abstract

Chromium carbide (Cr₃C₂) is valued for its outstanding chemical stability, oxidation resistance, hardness, and thermal durability, making it essential for protective coatings, cutting tools, and wear-resistant components. Conventional Cr₃C₂ synthesis typically requires high temperatures and reducing atmospheres, leading to high energy consumption and significant equipment wear. Recently, we demonstrated that mechanochemical synthesis provides a more energy-efficient route, producing Cr₃C₂ with enhanced electrical conductivity and enabling its use in high-tech applications such as conductive fillers for fuel-cell electrodes. However, achieving single-phase Cr₃C₂ by ball milling remains challenging due to incomplete reaction and mixed-carbide formation, often requiring a subsequent annealing step at ∼800 °C. In this study, we systematically investigate the influence of applied pressure and temperature on the mechanochemical formation of Cr₃C₂ to optimize phase purity and electrical performance. We show that increasing pressure significantly enhances phase selectivity, yielding Cr₃C₂ with superior conductivity and eliminating the need for post-annealing. This work establishes pressure-assisted mechanochemistry as an efficient and scalable pathway for producing high-purity Cr₃C₂ for advanced energy and coating applications.