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Hard Coatings: Diamond-like Carbon (DLC) and Tungsten Carbon Carbide (a.k.a. Tungsten-DLC or WCC)

Diamond-Like Carbon

Diamond-like carbon coated bearings

NHBB offers advanced surface coating solutions on miniature & instrument bearings to improve wear resistance and reduce heat and friction in demanding customer applications. Part of this offering includes hard, thin-film coatings like diamond-like carbon (DLC) and tungsten-DLC (tungsten carbon carbide), a.k.a. WCC.

These specialized, hard coatings provide increased bearing performance when the factors responsible for life-limiting bearing wear – corrosive conditions, high operating temperatures, dry bearing operation, negative pressure, etc. – are too extreme for standard oil- or grease-lubricated bearings.

Diamond-like carbon (DLC) and tungsten-DLC (WCC) exhibit high hardness and a low coefficient of friction over a wide operating temperature range, which contribute to high abrasive wear resistance, low heat generation, and no cold welding in poor lubrication conditions.

Both coatings possess good to excellent adhesion to bearing surfaces. This makes them highly resistant to flaking or chipping, with WCC offering more protection at high speeds. Furthermore, these hard coatings are corrosion resistant, nontoxic, and biocompatible, which is necessary for medical applications. They even stand up to repeated autoclaving, another important requirement within the medical industry.

NHBB’s ongoing research into different mixes of conventional lubricants and special coatings has shown that, for each specific coating, there is an optimal coating thickness that delivers increased tribological benefits. DLC and WCC are usually applied to bearing surfaces through physical or chemical vapor deposition (PVD or CVD) to thicknesses up to 5 micrometers.

Selecting the optimal thickness is a relatively simple task for most commercial uses, but it takes significant research to provide the optimal solution for unique or critical applications. NHBB is prepared to work with you to optimize the coating thickness so it adheres properly to the substrate and delivers the required wear resistance and life expectancy. Whenever possible, we’ll try to specify a coating thickness that precludes the need to resize the parts to accommodate a new layer.

With our variety of coatings and familiarity with many different bearing environments, NHBB can provide the optimum combination of bearing design, lubricant, and coating to deliver the exact characteristics that each customer needs.

Download a tech brief on Diamond-Like Carbon.

Contact the Precision Division’s applications engineering department for more information about hard, thin film coatings.