2017 Volume 58 Issue 678 Pages 611-616
Environment issues have restricted the industry-wide trend to reduce the amount of Cl or P additive used for lubrication in metal forming. Diamond like carbon （DLC） has superior tribological properties such as low friction and wear resistance under poor lubrication. However, DLC has never been applied to severe forging in metal forming. Thus, we focused on a Si-containing DLC （DLC-Si） coating with high adhesion strength, which has been used in the sliding parts. The combination of DLC-Si and polymer-containing oil without S or P additive, was evaluated by the ball penetration test. An observation of the workpiece and the DLC-Si coated ball also indicated a high lubrication performance of the combination. The low friction working of the combination is probably different from that due to the high viscosity of polymer-containing oil. We found that DLC-Si coatings with polymer-containing oils have a great potential to reduce friction and wear. It would suggest that strong adsorption on DLC-Si coatings is effective for lubricating for the combination of DLC-Si coatings and polymer-containing oils.
