Preparation of Al₂O₃-Ti₃SiC₂ agglomerated powder for plasma spraying

High-temperature microwave-absorbing materials play a crucial role in enhancing the stealth capabilities of hot-end components in advanced warplanes. Among them, Al₂O₃ and Ti₃SiC₂ have a wide range of applications in this field. However, the two powders have poor fluidity after physical mixing, which makes them difficult to use directly for plasma spraying, so secondary granulation is required. In this research, agglomerated powders composed of Al₂O₃ and Ti₃SiC₂ are successfully prepared using centrifugal spray drying. The study indicates the influence of various factors, including slurry solid content, PVA solution content, spray disk rotational speed, inlet air temperature, and outlet air temperature, on the morphology, surface roughness, and particle size distribution of the agglomerated powders.The results show that optimizing the content of solid and PVA in the slurry is beneficial to improve the sphericity and surface roughness of the powder, controlling the rotational speed of the spray disk can effectively control the particle size distribution of the powder, and a reasonable inlet/outlet temperature will help to further improvement of the sphericity of the powder. Optimal conditions for producing high-quality agglomerated powders are: 60% solid content, 3% PVA solution content, a spray disk rotational speed of 40 r·min⁻¹, an inlet air temperature of 250 ℃, and an outlet air temperature of 130 ℃. Under these conditions, the agglomerated powders exhibit high sphericity, low surface roughness, a bulk density of 1.92 g·cm⁻³, a fluidity of 37.1 s/50 g, and a tightly concentrated particle size distribution（D₁₀ = 30.1 μm, D₅₀ = 56.7 μm, and D₉₀ = 90.1 μm）. These powders, obtained through this method, can be directly utilized in plasma spraying and are suitable for large-scale production, thereby holding significant promise for the research and development of high-temperature wave-absorbing materials based on Al₂O₃ and Ti₃SiC₂.