Powder jet machining can be used for both material removal (abrasive jet machining) and material deposition processes (powder jet deposition) by changing the powder spray conditions. The transition from the removal to the deposition is investigated. The transition between these two phenomena, removal and deposition, is studied through simulating the impact phenomena of two alumina particles with a glass substrate using the Smoothed Particle Hydrodynamics (SPH) method in this study. Crystalline structures of an alumina film created were observed with a Transmission Electron Microscope (TEM). Observation indicates that a thick multicrystalline film is created when the blasted particles are monocrystalline alumina. It is also concluded that fractures within the particle material are necessary for the deposition process, and that fragments less than 100 nm in size contribute to the deposition of the thick films.