Study On Diamond-like Carbon Film Prepared By Liquid Electrochemical Method

Diamond-like carbon?DLC?film is composed of diamond structure?sp³?and graphite structure?sp²?,and it is considered as promising material in the fields of machinery,electronics,optics and aerospace parts because of its excellent properties which are similar to diamond film,such as high hardness,good chemical stability,high optical transmittance and relatively wide optical band gap.Compared with the preparation of diamond film,the preparation of DLC film utilizes simpler equipment under milder conditions.In this work,DLC films were prepared by liquid electrochemical method,and the influence of electrode distance,concentration of electrolyte and concentration of nitrogen doped on the surface morphology,structure and properties of films have been discussed.The main work and conclusions of the experiment are as follows.DLC films were obtained from pure dimethyl sulfoxide at 140 V.Raman tests illustrate the films prepared have typical diamond-like structure.SEM and AFM images indicate that films are composed of homogeneous nanoparticles,and the increase of electrode distance increases the surface roughness of the film.The electrochemical tests show that as-prepared DLC film electrodes have wide potential windows in 0.5 mol·L^-1 H₂SO₄ solution.The cyclic voltammograms curves of[Fe?CN?₆]^3-/4-on film electrodes have not shown obvious oxidation and reduction peaks,which illustrate that as-prepared DLC film electrodes have not shown obvious electrochemical activity.In brief,current density changed with the electrode distance,so the morphology,structure and properties of thin films have been changed.DLC films were obtained from the mixture of dimethyl sulfoxide and water at140 V.The results of Raman spectra after fitting show that the G peak move down and I_D/I_G decrease with water content,which indicate that sp³ hybridization content in the membrane has increased.SEM images indicate that films are composed of homogeneous nanoparticles.Tafel tests show that DLC films have excellent corrosion resistance,and the film obtained from 5%?v/v?dimethyl sulfoxide aqueous solution exhibits the best corrosion resistance,since the film have the most abundant sp³hybridization and least defect.Nitrogen-doped DLC films were obtained from the mixture of dimethyl sulfoxide and carbamide at 140 V.EDX analysis shows that film mainly contain C,N,O,H.Raman spectra indicate that the proportion of sp²-C and disordered structure in the film increase with carbamide content.According to SEM and AFM images,films are composed of homogeneous nanoparticles,and the introduction of nitrogen decreases the surface roughness of film.The electrochemical tests of indicated that DLC:N film electrodes have wide potential windows in 0.5 mol·L^-1 H₂SO₄ solution,which have showed no obvious catalytic ability of decomposition of water.The cyclic voltammograms curves of[Fe?CN?₆]^3-/4-on film electrodes appear obvious oxidation and reduction peaks at slow scanning speed,which illustrate that as-prepared DLC:N film electrodes haven't shown particularly outstanding electrochemical activity.