Effect of powder morphology on the structure and properties of Al2O3 based coatings obtained by detonation spraying

Aluminum oxide (Al2O3) remains a crucial material in the field of engineering ceramics, particularly in industrial applications. Notably, its transitional phases, in addition to the α-phase, demonstrate good properties. In this article the structure and properties of coatings obtained by detonation spraying from aluminum oxide powder with different production methods (fragmentation and spherical particle shape) and crystalline modification (α-Al2O3 and γ-Al2O3) but with similar average particle size were studied. The goal of the study was to investigate the influence of the morphology and phase composition of the powder on such properties of the coatings as microstructure, porosity, roughness and hardness. The results of the study showed that agglomerated spherical powder leads to low porosity of the coatings, while crushed fragmentation particles provide dense layers. In addition, the coating obtained using fragmentation powder showed higher hardness, and the surface had twice the roughness, compared to the coating applied using spheroidal powder. These results confirm the effect of the morphology of the original powder on the final properties and efficiency of the coatings. The study showed that the detonation spraying method allows for the efficient application of coatings from two types of Al2O3 powders with different morphology (spherical and fragmentation) and phase composition (γ-Al2O3and α-Al2O3) but with similar particle sizes.