Method and device for nanosecond pulse laser-assisted preparation of nano-diamond

Abstract

The invention relates to a method and device for nanosecond pulse laser-assisted preparation of nano-diamond. A mixed liquor of graphite powder and deionized water is exposed to nanosecond pulse laser irradiation generated by a laser generator, the graphite powder absorbs the laser energy and then rapidly generates high-temperature high-pressure plasmas, and during the nanosecond-level extremely non-equilibrium process, diamond nucleates and grows. Conical high-pressure gas jetted out of a conical nozzle forms a barrier to a trace amount of splashing liquid during the reaction, so as to protect a laser head and recover the splashing liquid and increase the synthesis efficiency of nano-diamond. The method and device provided by the invention solve the problem in the prior art that the synthetic diamond method has harsh conditions or low synthesis efficiency, achieves the effect of synthesizing diamond nanoparticles under normal temperature and normal pressure, ensures that the synthesized nano-diamond has good dispersion and uniformly size distribution, and has significant application in the aspects of ultra-precision machining and lubrication.

Description

technical field [0001] The invention belongs to the field of artificially synthesized nano-diamonds, in particular to a method and a device for synthesizing nano-diamonds by irradiating graphite with high-power pulsed laser at normal temperature and pressure. technical background [0002] Nanoscale diamond has a high grain boundary density and size effect, so it shows unique properties in magnetism, nonlinear optics, light emission and absorption, photoconductivity, etc., and has a wide range of applications in the fields of machinery, optics, and electronics. prospect. [0003] At present, the methods of obtaining nano-diamonds are mainly detonation method and chemical vapor deposition method. The two methods have harsh reaction conditions and require high temperature and high pressure conditions, and the purification process of detonation ash in the later stage of detonation method is complicated; chemical vapor deposition method can only obtain Diamond film, and it is di...

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Problems solved by technology

[0003] At present, the methods of obtaining nano-diamonds are mainly detonation method and chemical vapor deposition method. The two methods have harsh reaction conditions and require high temperature and high pressure conditions, and the purification process of detonation ash in the later stage of detonation method is complicated; chemical vapor deposition method can only obtain diamond film, and it is difficult to obtain granular diamond in the products of the above two methods

[0004] In recent years, Wang Jinbin and others have synthesized nanoscale diamonds by using laser shocks on solid graphite targets in liquids, but the synthesis efficiency is low by relying on the intermittent method of collecting graphite sputtering liquid

Sun Jing and others synthesized nano-diamonds by bombarding graphite suspension with millisecond pulse laser, but there was a problem of liquid sputtering during the synthesis process. The sputtering liquid polluted the laser focusing mirror, and the surface stability of the suspension was poor, which affected synthetic efficiency

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