Oerlikon Balzers, Liechtenstein, August 29, 2019 – Oerlikon Balzers, a leading supplier of surface technologies, has developed new amorphous hydrogen-free carbon (a-C) coatings, BALIQ CARBOS and BALIQ CARBOS STAR, which deliver an exceptional combination of high hardness, low friction and low roughness for applications with extreme contact pressures and sliding velocities.
The BALIQ CARBOS and BALIQ CARBOS STAR coatings are very versatile and best utilised in applications with high contact pressure combined with sliding velocities, such as in all high-performance motorsport vehicles specifically for applications such as the camshaft, piston pins, valves, lifters and finger followers. The coating is also used within the general industries’ market for applications such as weaving reeds, valve plates and valve stems and in pneumatic valves.
The coating technology of tomorrow
In a proprietary process developed by Oerlikon Balzers, BALIQ CARBOS and BALIQ CARBOS STAR coatings are applied utilising Scalable Pulsed Power Plasma (S3p), which combines the advantages of the arc evaporation and sputtering methods. Arc evaporation is known for producing dense coatings with high adhesion. Sputtering, a conventional coating technology where atoms are ejected from a target or source material to be deposited on a substrate, is known for high levels of smoothness.
The result is a hydrogen-free DLC coating that delivers the benefits of low friction carbon coatings with the smoothness achieved by sputter- or PACVD-applied coatings without additional polishing treatments.
New dimensions in hardness, durability and smoothness
The S3p technology also generates a high fraction of tetrahedral bonds (50-60%) to a hardness up to 40 GPa (indentation hardness, HIT). In comparison, typical DLC coatings achieve hardness levels in the range of 20-30 GPa and only 10-15 for WC/C coatings. The coatings exhibit three times lower abrasive wear than a 20 GPa hard DLC coating as measured by a calo test.
The coating process operates at a relatively low temperature, below 200 degrees Celsius as compared to up to 350 degrees for other DLC coatings, which enables its application to a much wider selection of substrates, including aluminum and steel.
For applications that require maximum load bearing capacity, BALIQ CARBOS STAR provides even higher tribological performance. This modified coating provides the required surface hardness and significantly improves resistance in high load bearing applications.
Because maximum load bearing capacity also depends to a large extent on the substrate, an additional chromium nitride-based layer is added to BALIQ CARBOS STAR to resist extreme loadings when using softer substrates like stainless steel and titanium – or substrates that are subject to continuous knocks.