Plasma-sprayed　ceramic　coatings　are　deposited　by　flattened　splats　together　with　some　nonmelted　particles.　In　this　study,　both　nonmelted　particles　and　molten　splats　in　plasma-sprayed　alumina　coatings　were　examined　by　a　combination　of　scanning　electron　microscopy,　x-ray　diffraction　analysis,　and　confocal　Raman　analysis　to　aim　at　the　comprehensive　understanding　and　quantitative　evaluation　of　coating　microstructure.　Results　showed　that　the　nonmelted　particles　can　be　clearly　identified　from　the　polished　cross　section　due　to　the　raised　pattern　morphology　(with　convexes)　resulting　from　the　higher　hardness　of　the　nonmelted　particles　than　molten　splats.　Raman　analysis　revealed　that　there　was　little　alpha-Al2O3　phase　in　the　flattened　splat　region,　which　confirmed　that　alpha-Al2O3　phase　in　the　coating　originated　only　from　nonmelted　particles.　Moreover,　it　is　proposed　that　attention　should　be　paid　to　the　weak　bonding　of　the　nonmelted　particles　to　surrounding　flattened　splats　during　the　preparation　of　samples　for　the　quantitative　characterization　of　coating　microstructure.