It is well accepted that the morphology and microstructure of the splats have a strong influence on the characteristics and properties of thermally sprayed coatings. McPherson has made pioneering and outstanding contributions in the above area, especially for plasma sprayed coatings. Recently, splat morphology - microstructure - properties correlation has also been attempted in the case of HVOF thermal spray coatings. However, only limited data is available in the case of detonation sprayed coatings inspite of the fact that DS coatings have been available commercially for a long time. In the present work, the influence of particle velocity and temperature on the splat morphology and also area coverage of the splat has been studied for detonation sprayed Al2O3 particles on a mild steel substrate. Further, the effect of two detonation spray process variables namely, oxy fuel ratio and shot frequency on splat morphology and splat area coverage has been evaluated. The above correlation has then been utilized to understand the variation of deposition efficiency of detonation sprayed Al2O3 coatings on mild steel as a function of spray process parameters.