The　bonding　at　the　interface　in　cold　sprayed　coating　is　considered　to　be　a　very　crucial　factor　determining　its　mechanical　properties,　physical　and　chemical　behavior　such　as　tensile　strength,　hardness,　electrical　and　thermal　conductivities,　as　well　as　corrosion　resistance.　Therefore,　in　this　study　the　deformation　behavior　of　the　particle　initial　surface　is　investigated　in　order　to　reveal　the　evolution　of　free-oxide　interface　during　the　high-velocity　particle　impact　in　cold　spray.　The　variation　of　the　stress　at　the　interface　during　the　impact　is　also　examined　to　evaluate　the　bonding　between　particle　and　substrate,　and　further　to　predict　the　bonding　strength　for　the　experiments.　Results　show　that　the　area　ratio　of　the　free-oxide　interface　and　the　whole　interface　are　0.52,　0.7　and　0.76,　respectively,　for　the　case　of　copper　particle　impact　at　500　m/s,　800　m/s　and　1100　m/s.　Moreover,　the　free-oxide　interface　in　case　of　800　m/s　is　about　3　times　as　much　as　that　in　case　of　500　m/s　while　the　free-oxide　interface　of　1100　m/s　is　approximately　5　times　as　much　as　that　of　500　m/s.　The　compressive　stress　in　the　normal　direction　at　the　position　where　free-oxide　interface　occurs　is　higher　than　the　yield　strength　of　the　material　and　during　the　whole　impact,　the　tensile　stress　is　no　more　than　the　tensile　strength　of　the　material.　©　Copyright　2017　by　DVS　Media　GmbH.　All　rights　reserved.