Feasibility Study Of DLC Coating Preparation For Complex Shape Industrial Mold

DLC coatings have been used in small-sized molds and have achieved good results,but have less application on complex-shaped molds.In order to explore the application feasibility of DLC coating on complex shape industrial molds,this paper takes tire mold as the research object,and mainly study the following aspects:?1?The design of simulating samples and preparation of DLC coating.The design of the simulating sample was based on the typical pattern characteristics of the tire mold.Hydrogen-based diamond-like coating?H-DLC?and fluorine-doped diamond-like coating?F-DLC?were deposited on the matrix?S35C?by magnetron sputtering combined with plasma enhanced chemical vapor deposition?PECVD?.?2?Study on the hydrophobic properties of DLC coatings on multiple feature surfaces.In order to study the demolding and cleaning performance of the tire mold DLC coating,the coating surface morphological,thickness,and cross-sectional morphological analyses of the samples were performed using SEM,EDS spectrum and white light interferometer.Water contact angles,alcohol contact angles and surface energy were measured by an optical contact angle meter.The research shows that the hydrophobic properties of the multiple feature surfaces of the two DLC coatings are good,which meets the demolding requirements.?3?Study on nano hardness and bond strength of DLC coatings.In order to study the ability of the tire mold DLC coating to resist detachment and to resist damage,the scratch test and hardness test were performed on the two DLC coatings using a scratch tester and a nanoindenter.The research shows that the hardness and bond strength of the two DLC coatings meet the tire mold working requirements.The hardness and bond strength of the H-DLC coating are more excellent,and its critical load Lc₂ is 61.77N,hardness is19.86GPa and elastic modulus is 162.56GPa.The bond strength increases as the pattern angle and the width-depth ratio increase.?4?Study on friction and wear of DLC coatings.In order to study the influence of rubber flow and rubber vulcanization on the mold surface when DLC coating is working,the friction and wear test machine was used to simulate the rubber vulcanization environment,and the friction and wear experiments were carried out on the surface of the matrix and the two DLC coatings.The research shows that the two DLC coatings have good friction and wear characteristics,which can provide protection for the matrix and reduce friction and wear resistance.The F-DLC coating has good friction and wear properties,when the roughness is 55 nm,the friction coefficient is 0.1835 and the wear amount is 0.011g.After experimental research,when the pattern angle is greater than 105°and the width-to-depth ratio is greater than 1.5,the deposition of the DLC coating on the groove is facilitated.The surface characteristics and working performance of the two DLC coatings meet the tire mold work requirements,and have the conditions for becoming the surface coating of tire mold.Among them,F-DLC coating has better application prospects in industrial molds.