Study On Electrochemical Deposition Of Diamond-like Carbon Films In Aqueous Solution

Diamond-like carbon film(DLC)is very similar to diamond film because of its various characteristics,so it can be applied to many fields(chemistry,optics,electricity,tribology,etc.).At the same time,the preparation process of the diamond-like film and the process conditions required for its preparation are simpler and more energy-saving than the conditions required for the preparation of the diamond film.The development of the preparation technology of DLC films is also becoming more and more perfect,and the electrochemical deposition technology has attracted widespread attention.However,during the preparation of electrochemically deposited DLC films,there are some non-negligible defects,such as excessive residual stress in the film,heat intolerance,and low adhesion to the substrate,which greatly limits the research on it.In this paper,a chlorocarboxylic acid aqueous solution is used as the electrolyte to electrochemically deposit DLC films in the aqueous solution.The effects of different electrolytes,different deposition conditions,and different amounts of phosphorus doping on the structural composition,surface morphology,thickness and conductivity of the film are studied.,The experiment content and results are as follows:1.Study on Electrochemical Deposition of Diamond-like Carbon Films in Chloroacetic Acid Aqueous SolutionIn this part,an aqueous solution of acetic acid substituted with different numbers of chlorine atoms is used as the electrolyte.The DLC film is electrochemically deposited under the conditions of a voltage of 3.0 V,a time of 15 min and a temperature of 25?,and investigates the substitution of different numbers of chlorine atoms in the acetic acid aqueous solution.The effect of the substitution quantity of chlorine atoms on the structure,morphology,thickness and conductivity of diamond-like carbon films.The experimental results show that DLC films can be successfully prepared in these several aqueous solutions,and the morphology,thickness and conductivity of the films deposited in chloroacetic acid aqueous solutions are better than other electrolytes.In dichloroacetic acid and trichloroacetic acid The DLC film deposited in the aqueous solution is very easy to fall off,the film thickness is low,and the conductivity decreases.It is inferred that the difficulty of electrochemical deposition of diamond-like carbon films in aqueous chloroacetic acid is chloroacetic acid,acetic acid,dichloroacetic acid,and trichloroacetic acid in order from easy to difficult.2.Study on Electrochemical Deposition of Diamond-like Carbon Films in Aqueous Organic Acids with Different Carbon Chain LengthsThis part uses chloroacetic acid,3-chloropropionic acid,4-chlorobutyric acid,and 5-chloropentanoic acid aqueous solutions as electrolytes,electrochemically deposits DLC films,and explores when chlorocarboxylic acid aqueous solutions with different carbon chain lengths are used as electrolytes.Influence on the structure,morphology,thickness and conductivity of the deposited film.The experimental results show that the parity of the carbon chain length of organic acid has a great influence on the electrochemically deposited diamond-like carbon film.When the carbon chain length of the organic acid is odd,the particle size of the deposited film is very small,and there is no obvious gap between the particles.The surface of the film is very flat,but the thickness and conductivity of the film are average;when the organic acid carbon chain length is an even number,the particle size of the deposited film is large,the gap between the particles is large,and the adhesion to the substrate decreases when the film thickness increases.It is easy to fall off,but the conductivity of the film is better.3.Study on Electrochemical Deposition of Phosphorus Doped Diamond-like Carbon Films in Chloroacetic Acid Aqueous SolutionIn 0.1 mol(?)L^-1chloroacetic acid aqueous solution,0-100 ppm phosphoric acid was added as the dopant,and the phosphorus-doped diamond-like carbon(P-DLC)film was prepared by electrochemical deposition method,and the doping amount and existence of phosphorus element were explored The influence of the form on the morphology,thickness and conductivity of the film.By comparing the surface morphology and structure of the deposited film with the thickness and conductivity data of the film,it can be seen that adding a suitable concentration of dopant phosphoric acid can significantly increase the thickness and conductivity of the film.After changing different reaction conditions,the optimal conditions for electrochemical deposition of phosphorus-doped diamond-like carbon films can be determined as follows:phosphoric acid 30 ppm,low voltage of 3.5 V,and time of 10 min.At this time,the content of phosphorus in the film is 1.8%.It can be seen that reasonable control of the amount of phosphorus doped can indeed improve some of the defects in the preparation of DLC films by electrochemical deposition.