Oxidation and laser ignition characteristics of Mn, Mo, Ta, and W powders in oxygen-rich environments

Manganese (Mn), molybdenum (Mo), tantalum (Ta), and tungsten (W) powders offer exceptional properties such as high strength, combustibility, and substantial volumetric combustion enthalpy, making them valuable for aerospace and industrial applications. This study investigates their oxidation and burning characteristics through thermogravimetric-differential scanning calorimetry and high-pressure combustion tests. Onset oxidation temperatures were determined as 340.23 degrees C, 475.01 degrees C, 523.90 degrees C, and 535.70 degrees C for Mn, Mo, Ta, and W, respectively. Mn forms Mn2O3 and Mn3O4, with combustion products exhibiting surface holes as substance migration channels. Mo and W form volatile oxides (MoO3, WO3) sublimating above 800 degrees C and 1200 degrees C, respectively, while Ta forms stable Ta2O5. Luminous intensity measurements quantified combustion evolution, revealing ignition delay times of 64 ms, 77.5 ms, 97.8 ms, and 128 ms for Mn, Mo, Ta, and W under 0.5 MPa oxygen, with Mn and Ta showing intense flames and faster reaction rates. Scanning electron microscope and X-ray diffraction analyses identified Mn3O4, MoO3, Ta2O5, and WO3 as primary combustion products. This study provides insights into the oxidation and combustion behaviors of high-density metal powders, supporting improved safety in powder metallurgy, 3D printing, and energetic material design. (c) 2025 The Society of Powder Technology Japan. Published by Elsevier BV and The Society of Powder Technology Japan. All rights are reserved, including those for text and data mining, AI training, and similar technologies.