Basic concept and characteristics of DLC coating

"DLC" is the abbreviation of "DIAMOND-LIKE CARBON" in English. DLC is a kind of material composed of carbon element, which is similar to diamond in nature, and has a structure of graphite atoms. Diamond like carbon (DLC) film is a kind of amorphous film, which can be basically divided into hydrogen containing diamond-like carbon (a-C: H) coating and hydrogen free diamond-like carbon coating. The hydrogen content of hydrogen containing DLC coating is between 20% - 50%, and the SP3 composition is less than 70%. Tetrahedral amorphous carbon (ta-c) film is common in hydrogen free DLC coating, and sp3 bond is dominant in ta-c coating, generally higher than 70%. DLC thin films have high hardness, high elastic modulus, low friction coefficient, wear resistance and good vacuum tribological properties, which are very suitable for use as wear-resistant coatings.

Typical application of DLC coating:

1) Cutting tools: drill bits, milling cutters, carbide inserts (for processing non-ferrous metals).

2) Metal material forming die: punch, die, precision blanking, stamping forming parts.

3) Mold forming: mold cavity and core, ejector pin and various inserts.

4) Engine parts: valves, piston pins, ejector rods, pistons.

5) Other parts: shafts, gears, bearings, cams, etc.

The company introduced the professional DLC coating equipment PL1068 from Switzerland, and deposited DLC2 (a-C: H) coating and DLC3 (ta-c) coating by combining magnetron sputtering with PECVD. The hardness of DLC2 is 2500HV, and the friction coefficient is 0.2. The hardness of DLC3 coating is up to 6000HV, and the friction coefficient is 0.1. The excellent performance has attracted many tool manufacturers and die manufacturers.