Nickel-cobalt　alloys　were　electrodeposited　on　copper　sheets　in　sulfate　bath　containing　288.5　g/l　NiSO4　center　dot　6H(2)O,　30　g/l　CoSO4　center　dot　7H(2)O,　40　g/l　HBO3,　15　g/l　NaCl　and　0.08　g/l　lauryl　sodium　sulfate.　The　effects　of　cobalt　content　on　microstructure,　microhardness,　and　wear　resistance　of　electroplating　nickel-cobalt　alloys　were　studied　by　using　SEM　and　XRD　techniques,　and　microhardness　tester　and　wear　tester.　The　relationship　between　the　microhardness　of　nickel-cobalt　alloy　coatings　and　heat　treatment　procedures　was　also　investigated.　The　experimental　results　show　that　cobalt　content　(W-t)　in　coating　increases　with　Co2+/(Co2+　+　Ni2+)%　(X)　in　plating　solution.　Fitted　regression　equation　is　as　following:　W-t　=　-0.7399　+　2.2847X　-　0.0133X(2).　The　increase　of　cobalt　content　leads　to　that　the　longitudinal　section　morphology　of　coating　transforms　from　the　cone　into　sphericity　and　at　last　into　the　shape　of　willow　leaf,　and　its　structure　transforms　from　face　centered　cubic　(fcc)　nickel　solid　solution　into　fcc　cobalt　solid　solution　and　at　last　into　hcp　cobalt　solid　solution.　The　increase　of　cobalt　content　results　in　the　increase　of　microhardness　of　nickel-cobalt　alloy　coatings,　and　the　hardness　reaches　a　maximum　value　(363　HV)　when　cobalt　content　is　54.9%.　After　heat　treatment　at　400　degrees　C　and　600　degrees　C,　the　microhardness　of　coatings　begins　to　decrease　except　the　coating　containing　79.2%　Co.　Moreover,　the　wear　resistance　of　electroplated　coatings　increases　with　the　increase　of　cobalt　content.