▎ 摘　　要

NOVELTY - Preparation of graphene-modified composite powder involves mixing 10 ml graphene oxide solution and 1-5 mol starch, adjusting pH of resultant solution to 7-9 using sodium hydroxide, obtaining a reducing liquid, dripping 10 ml oxidizing solution, reacting at 50-90 degrees C for 3 hours, centrifuging at 8000 rpm for 10 minutes, washing resultant solid, drying at 80 degrees C, sintering at 200 degrees C for 2 hours, cooling, mixing resultant with graphene-modified lanthanum stannate powder, ball milling for 4-8 hours, mixing for 4 hours, drying and sieving using 200 mesh sieve. USE - Preparation of graphene-modified composite powder used for preparing electrical contact. ADVANTAGE - The method enables preparation of graphene-modified composite powder having excellent electroconductivity. The graphene-modified composite powder enables manufacture of electrical contact having excellent elongation and low resistivity. DETAILED DESCRIPTION - Preparation of graphene-modified composite powder involves adding lanthanum chloride and tin nitrate in molar ratio of 1:1 to deionized water, stirring, dissolving, obtaining a mixed solution (s1), mixing graphene oxide and deionized water, obtaining graphene oxide solution having concentration of 2 g/L, mixing resultant with solution (s1) in volume ratio of 1:10, ultrasonically dispersing for 0.5-2 hours, stirring, adding a gelling agent, adjusting pH value of resultant mixture to 7-9 using sodium hydroxide solution, stirring for 3-7 hours, centrifuging, separating solid, drying, grinding, vacuum-sintering at 800-1000 degrees C for 3-5 hours, cooling, obtaining graphene-modified lanthanum stannate powder (p1), mixing 10 ml graphene oxide solution and 1-5 mol starch, adjusting pH of resultant solution to 7-9 using sodium hydroxide, obtaining a reducing liquid, dripping 10 ml oxidizing solution, reacting at 50-90 degrees C for 3 hours, centrifuging at 8000 rpm for 10 minutes, washing resultant solid, drying at 80 degrees C, sintering at 200 degrees C for 2 hours, cooling, mixing resultant with powder (p1) in mass ratio of 40:60, ball milling for 4-8 hours, mixing for 4 hours, drying and sieving using 200 mesh sieve. The oxidizing agent comprises silver nitrate solution having concentration of 0.1-0.5 mol/L. An INDEPENDENT CLAIM is included for preparation of electrical contact.