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Adopting suitable pretreatment,a compact and even nickel-phosphorus alloy coating was obtained on W-Cu alloy by electroless deposition from solutions containing nickel sulphate as a source of nickel and sodium hypophosphite as the reducing agent and a source of phosphorus.The Ni-P coating was prepared from acidic baths maintaining at 90 ℃ with the pH of 4.8.The microhardness,adhesion and corrosion resistance mechanism of Ni-P deposit and its various states at various tempering temperatures were studied.The microhardness of the Ni-P alloy deposit increases much more by tempering at various temperatures.The Ni-P deposit has a qualified adhesive force with W-Cu alloy substrate checked by thermal shock test and scribe test and the adhesive force is increased firstly and then decreased with the increasing of tempering temperature.