Preparation And Application Research Of Composited Diamond-like Carbon Films

Diamond-like carbon?DLC?film similar to diamond film,with excellent properties like high hardness,low friction coefficient,wear resistance,corrosion resistance,chemical stability,etc.,has great application prospects as new functional thin film material for surface protection as well as solid lubrication.The application process of DLC film began in the mid-1980s,but so far DLC film still has not been large-scale applied throughout the world.The main reason is that several key problems such as low adhesive stress,poor toughness and tribological instability which restrict the mechanical and tribological performance of DLC film.Therefore,how to change the film design concept,develop new DLC film so as to improve the comprehensive properties of DLC film,has great realistic and social value of realizing the the large scale application of DLC film in the world.From the perspective of theory and practical application,DLC composite films were designed and prepared to prolong the service life of composite material cutting tools and improve the surface quality,as the hinge for the accomplishment of micro and meso scale components/structure composite manufacturing,which included:?1?The hydrogenated amorphous carbon??-C:H?films were synthesized by anode linear ion source technology.The preparation principle and growth mechanism were analyzed.Different ion source voltage?400V-1000V?,pulsed negative bias voltage?-600V?-1400V?and substrate temperature?50°C?250°C?were applied to study the influence rule on the film morphology,microstructure,adhesive strength,toughness and wear resistance.The best comprehensive mechanical properties were achieved at ion source voltage of 1000V,pulsed negative bias voltage of-1400V,and substrate temperature of 100°C.?2?The Ti doped DLC?Ti-DLC?composite films were synthesized by medium frequency magnetron sputtering technology.The preparation principle and growth mechanism were analyzed.Different medium frequency current?2A?6A?,Ar flow rate?40sccm?120sccm?and pulsed negative bias voltage?-400V?-1200V?were applied to study the influence rule on the film morphology,microstructure,adhesive strength,toughness and wear resistance.The best comprehensive mechanical properties were achieved at medium frequency current of 5A,Ar flow rate of 100sccm and pulsed negative bias voltage of-800V.?3?The modulation period and modulation ratio of DLC multi-layer composite films were changed to study the influence rule on the comprehensive performance.While the modulation period was 366nm and the modulation ratio was 1:1,compared to a-C:H film,the adhesive strength increased from 97N to 1110N,CPRs increased from 2195N² to 2980N²,friction coefficient decreased from 0.1 to 0.08 and wear rate decreased from 1.13×10^-7mm³/?m·N?to 4.82×10^-8mm³/?m·N?.?4?Type-E Glass fiber reinforced plastics?GFRP?were dry turning by using the uncoated,?-C:H coated and DLC multilayer composite film coated cutting tools.The influence of different cutting depth,feed and cutting speed on the cutting process were investigated.From the perspective of tool wear,the service life of cutting tools was significantly extended after coated.All kinds of cutting tools exhibited abrasive wear morphology.In addition to that,coated cutting tools also showed film peeling off and failure.Compared with a-C:H coated cutting tool,DLC composite film coated cutting tools had obvious advantages on adhesive strength and wear resistence.From the perspective of surface quality,the surface roughness was lower and the defects of fiber extraction,fracture and bending were reduced when applied DLC coated cutting tools.From the choice of cutting parameters,machining GFRP should adopt small cutting depth,low feed rate and high cutting speed.?5?Theoretical research and test verification were carried out on the composite manufacturing for micro and meso scale components/structure.Taking grooves and steps as the verification objects,after precision cutting and DLC multilayer composite film compensation,the surface hardness increased from HV775.96 to HV1016.34,and the surface wear resistance was greatly improved with friction coefficient reducing from 0.75 to 0.08.What's more,the finish size finally achieved the design size 400?m and 700?m with precision grade of IT5.