DLC coating

DLC coating, also known as diamond like coating, combines high hardness (>HV2100) and lower dry friction coefficient (0.05-0.1), making it a coating that can achieve oil-free self-lubricating. This coating has an extremely low coating treatment temperature of up to 130 degrees, suitable for all metal materials and most non-ferrous metal substrates. The DLC coating does not change the effective size and surface roughness of the parts

The unique lubrication performance of DLC coating is widely used in engine components, non-ferrous metal cutting tools, non-ferrous metal and stainless steel forming and stamping molds, sliding sealing components, semiconductor industry molds, injection molds, textile industry, etc

DLC is a general term for carbon film coatings, and the specific performance needs to be adjusted according to the actual situation, such as workpiece material, processing conditions, and usage (friction coefficient, speed, pressure, etc.) to adjust the ratio of SP3 to SP2, achieve changes in thickness, wear resistance, hardness, and other indicators, and adapt to the specific usage situation of the workpiece.

The research data comes from the SKF official website: https://evolution.skf.com

The friction coefficient of coated bearings depends on the usage environment. Due to the ability to coat rings or rolling elements (or both), several different friction coefficients can be provided. The bearing with the lowest friction coefficient is a bearing with DLC coating on both the ring and rolling element. However, under dry conditions, coating DLC on only one surface can greatly prolong the wear life in sliding tests, but coating DLC on both surfaces can further prolong the wear life. The reason why DLC coating surface can prolong the service life of bearings is because the friction coefficient of this coating is very low and the surface hardness is very high. In fact, the friction coefficient is very similar to the friction value of low friction materials such as PTFE and MoS2, thus providing a stable lubrication effect.

There is an important difference between DLC and solid lubricants such as PTFE. DLC does not wear under high pressure. Another unique feature of DLC is the running in characteristics of the coating. Although it is very hard, a small portion of the surface will become a low friction contact area. This effect serves to protect the reverse side of the steel, otherwise these reverse sides will be damaged by the harder coating. This effect, combined with hardness, creates ideal solid lubrication conditions.