Preparation and characterization of micro-spherical ruthenium particles using spray drying combined with microwave calcination of ammonium hexachlororuthenate (IV)

Abstract

The quality of ruthenium (Ru) powders has a direct impact on the performance of sputtering Ru targets. This study employed spray granulation coupled with microwave calcination to prepare high-sphericity and uniform particle size Ru powders using ammonium hexachlororuthenate (IV) (AH). Spray granulation was applied to prepare AH powders with uniform particle size, high sphericity, and great dispersibility. AH@10, prepared by blending spherical AH powders and near-spherical Ru powders generated by microwave calcination at a mass ratio of 9:1, absorbs more microwaves than AH, which is promising for preparing Ru powders with faster and greater production than AH by microwave calcination. The response surface methodology (RSM) based on central composite design (CCD) was used to optimize the process of microwave calcination AH@10 in accordance with the thermal decomposition and self-reduction mechanism of AH. Three parallel verification experiments were performed under optimal microwave conditions (heating time 68.00 min, heating temperature 500 °C, and material mass 28 g), and the products were collected and characterized. The results show that the response surface model is accurate, and near-spherical Ru powder with high morphology was obtained after spray granulation and microwave calcination AH@10. This work is anticipated to produce Ru powders that could be used as a sputtering target in industry, as well as other high-performance metal powders.