Federal-Mogul Powertrain has announced an upgrade to its GOETZE Diamond Coating (GDC) for piston rings, a technology that has been used in heavy-duty diesel engine applications for more than a decade. The new coating, GDC60, features higher diamond content than the established GDC50 to further reduce wear and has demonstrated lower friction and greater scuff resistance during testing.
“GDC60 will enable our customers to develop new, more efficient engines with higher cylinder pressures while staying with a familiar, well-proven ring coating technology,” commented Gian Maria Olivetti, chief technology officer, Federal-Mogul Powertrain. “This means they can continue to benefit from design features such as the inlays and Blitzchrom flank protection that are already well established in the market with GDC50, as well as lower validation costs compared to a completely different ring coating technology.”
In rig tests, GDC60 reduced the friction coefficient up to 7% and first engine tests have shown the potential for wear reduction of up to 10% compared to GDC50 coatings. This will also benefit the function of the oil rings.
In order to provide GDC60 with greater scuff resistance under high thermal load conditions, Federal-Mogul Powertrain has improved upon the microstructure of GDC50, creating a finer microcrack network containing increased numbers of nanodiamond particles that are also more uniformly distributed.
When conventional fresh oils are used, GDC60 shows a scuff resistance improvement of up to 20% on already high levels of thermal load capacity; the improvement is even higher when operating with aged oil. Confirmation studies carried out with very low viscosity lubricating oils (HTHS2.6) demonstrated that GDC60 can withstand the same thermal load level as PVD (Physical Vapour Deposition) coatings.
For specific applications, increased scuff resistance in combination with the proven high level of robustness under borderline loads makes GDC60 the optimum technical option within conventional piston ring coating families. Initial results from endurance testing in a highly loaded heavy-duty engine have confirmed the results of the rig test investigations.