The　acceleration　effect　of　cobalt　on　carburization　of　tungsten　at　low　temperatures　was　studied　by　a　series　of　experiments　of　W,　C　and　Co　reactions　and　theoretical　evaluations.　Due　to　Co　addition,　the　formation　temperature　of　WC　was　greatly　reduced　(e.g.　a　decrease　from　1300　degrees　C　to　850　degrees　C　by　addition　of　1.0　wt%　Co).　Below　the　formation　temperature　of　the　ternary　phase,　the　converted　fraction　of　W　carburization　increases　with　increased　Co.　Modeling　of　reaction　kinetics　revealed　that　the　process　of　W　carburization　is　dominated　by　carbon　diffusion,　and　the　reaction　rate　constant　is　increased　much　with　the　increase　of　Co.　The　mechanism　was　proposed　that　Co　acts　as　the　medium　for　rapid　diffusion　of　C　atoms　and　promotes　W　carburization　by　accelerating　reaction　diffusion　kinetics.　The　present　findings　will　facilitate　to　develop　methods　for　synthesis　of　WC-Co　composite　powders　at　low　temperatures.　(C)　2017　Elsevier　B.V.　All　rights　reserved.