▎ 摘　　要

NOVELTY - A tone-adjustable nano-level sound generator comprises copper blocks, sound wave generating film and electrical signal input unit. The sound wave generating film is a graphene film prepared by formulating graphene oxide into aqueous solution of graphene oxide, suction filtering, performing fumigation, uniformly coating melted solid transfer agent on the surface of reduced graphene oxide film, cooling, heating the reduced graphene oxide film, allowing the solid transfer agent to sublimate or volatilize, spraying layer of metallic titanium, molybdenum or cobalt on the surface of chemically reduced graphene film by magnetron sputtering, chlorinating graphene film sputtered with metal at 800-1200 degrees C, and dispersing metal nanoparticles in the form of chloride, placing graphene film after chlorination in high temperature furnace, warming up to 5-20 degrees C at the rate of 1500 degrees C/minute and heating to 2-5 degrees C at the rate of 2000 degrees C/minute. USE - Tone-adjustable nano-level sound generator. ADVANTAGE - The tone-adjustable nano-level sound generator has excellent sound quality, high sound definition, and provides graphene film with excellent electrothermal properties, thermal conductivity. DETAILED DESCRIPTION - Tone-adjustable nano-level sound generator comprises copper blocks, sound wave generating film and electrical signal input unit. Both ends of the sound wave generating film are overlapped on the surface of the copper block. Two copper blocks are respectively connected to the positive and negative poles of the electrical signal input unit. The sound wave generating film is a graphene film with thickness of not more than 60 nm, density of 2.0-2.2 g/cm3 and crosslinking degree of 1-5% between graphene layers. The graphene film is prepared by (1) formulating graphene oxide into aqueous solution of graphene oxide with concentration of 0.5-10 mu g/mL, suction filtering, (2) placing graphene oxide film attached to suction filtration substrate in a closed container, performing fumigation at 80-100 degrees C for 0.1-1 hour, (3) uniformly coating the melted solid transfer agent on the surface of the reduced graphene oxide film, slowly cooling to room temperature, until the film and substrate are separated, (4) heating the reduced graphene oxide film, allowing the solid transfer agent to sublimate or volatilize, (5) spraying layer of metallic titanium, molybdenum or cobalt on the surface of chemically reduced graphene film by magnetron sputtering, (6) chlorinating graphene film sputtered with metal at 800-1200 degrees C, and dispersing metal nanoparticles in the form of chloride, (7) placing graphene film after chlorination in high temperature furnace, warming up to 5-20 degrees C at the rate of 1500 degrees C/minute and heating to 2-5 degrees C at the rate of 2000 degrees C/minute. The molar amount of sputtered metal nanoparticles is not more than 30% of the molar amount of carbon atoms in the graphene film.