This　paper　presents　our　detailed　investigation　into　the　effect　of　the　WC-Co　content　on　the　microstructure　and　properties　of　supersonic　plasma　sprayed　NiCrBSi　composite　coatings　on　Inconel　718.　The　results　showed　that　the　NiCrBSi/WC-Co　composite　consisted　predominantly　of　Ni,　Ni3Fe,　Ni3B,　CrB,　WC,　Cr7C3,　and　WFeB2,　in　addition　to　lesser　amounts　of　W2C,　Cr3Ni2Si,　and　Co3B.　The　coating　containing　15　wt　%　WC-Co　exhibited　the　most　compact　microstructure　with　the　lowest　number　of　defects,　as　well　as　the　lowest　porosity　(i.e.,　0.6%).　The　mechanical　properties　of　the　as-sprayed　coatings　were　significantly　enhanced　by　the　addition　of　WC-Co.　Upon　increasing　the　WC-Co　content,　the　friction　coefficients　of　the　as-sprayed　coatings　increased　from　0.59　to　0.74.　The　main　wear　mechanisms　transformed　from　abrasive　wear　coupled　with　spallation　for　the　NiCrBSi　coatings　with　a　low　WC-Co　content　to　adhesive　wear　and　fatigue　fracture　for　coatings　with　a　medium　WC-Co　content,　to　a　combination　of　brittle　fracture　failure　and　slight　abrasive　wear　for　coatings　with　a　high　WC-Co　content.　Furthermore,　the　coating　with　15　wt%　WC-Co　registered　a　higher　microhardness　(910.6　HV)　and　adhesive　strength　(44.7　MPa),　and　a　lower　wear　rate　(8　x　10(-6)　mm(3)　/(N　m))　than　the　other　as-sprayed　coatings,　indicating　that　this　was　the　optimal　WC-Co　content　for　this　type　of　NiCrBSi-based　composite　coating　on　Inconel　718.　The　synergy　between　the　compact　structure,　higher　microhardness,　and　adhesive　strength　was　considered　responsible　for　the　excellent　wear　resistance　of　the　NiCrBSi-based　composite　coating　with　a　WC-Co　content　of　15　wt%.　(C)　2019　Elsevier　B.V.　All　rights　reserved.