Hydroxyapatite　(HA)　coatings　are　usually　deposited　on　the　metallic　implant　to　increase　the　biocompatibility　and　protect　the　bloodstream　from　harmful　metal　ions.　Atmospheric　plasma　spray　(APS)　is　known　as　a　cost　effective　deposition　method.　However,　the　low　crystallinity　of　APS　deposited　coating　accelerates　its　dissolution　in　body　fluid.　We　used　micro-plasma　spray　(MPS)　to　develop　chemically　stable　HA　coatings,　and　performed　APS　as　reference.　Results　showed　that　MPS　deposited　coatings　exhibited　(002)　crystallographic　texture　while　the　reference　sample　did　not.　The　texture　intensity　and　crystallinity　were　improved　by　shortening　stand-off　distance.　These　suggested　that　different　formation　procedures　of　HA　coatings　were　involved　and　three　mechanisms　were　proposed　by　sketching　typical　splats.　To　evaluate　the　chemical　stability　of　the　coatings　in　a　physiological　environment,　in　vitro　experiments　were　performed　in　Hanks＇　solution.　Well　crystallized　(similar　to　100%)　HA　coating　with　the　strongest　crystallographic　texture　exhibited　superior　stability　up　to　14　days.　Crystals　with　(002)　orientation　was　more　stable　than　that　with　(211)　orientation.　Hence　columnar　structure　with　nanopores　emerged　on　the　coating　surface　after　incubation,　and　this　may　facilitate　the　future　osteoblast　growth.　Furthermore,　HA　coating　with　weak　and　no　crystallographic　texture　induced　apatite　layer.　However,　vertical　cracks　and　cleavage　at　coating-apatite　interface　may　cause　coating　separation.　(C)　2017　Elsevier　B.V.　All　rights　reserved.