Stable aqueous suspension liquid of finely divided diamond particles, metallic film containing diamond particles and method of producing the same

Abstract

An aqueous suspension liquid of finely divided diamond particles comprising 0.05 to 160 parts by weight of a finely divided diamond particles in 1000 parts of water, wherein; (i) the finely divided diamond particles have an element composition consisting mainly of 72 to 89.5% by weight of carbon, 0.8 to 1.5% of hydrogen, 1.5 to 2.5% of nitrogen, and 10.5 to 25.0% of oxygen; (ii) and, almost all of said diamond particles are in the range of 2 nm to 50 nm in diameters thereof (80% or more by number average, 70% or more by weight average), (iii) and, said finely divided diamond particles exhibit a strongest peak of the intensity of the Bragg angle at 43.9° (2θ±2°), strong and characteristic peaks at 73.5° (2θ±2°)and 95° (2θ±2°), a warped halo at 17° (2θ±2°), and no peak at 26.5°, by X-ray diffraction (XRD) spectrum analysis using Cu—Kα radiation when dried, (iv) and, specific surface area of said diamond particles when dry state powder is not smaller than 1.50×10m/kg, and substantially all the surface carbon atoms of said particles are bonded with hetero atoms, and the total absorption space of said powder is 0.5 m/kg or more, when dried. The diamond particles are very active and dispersible in aqueous liquid in stable, and have essentially same mechanical properties as that of usual diamonds.