A refinement of chrome ceramic coatings, Goetze Diamond Coating (GDC® 50) has proved its excellent wear-resistance in large bore engines. It is a hard chromium coating reinforced with minute diamond particles embedded in the extremely fine crack network.

• Compression rings
• Technological properties: Extremely high wear resistance, low cylinder wear, high thermal loading capacity
• Coating material: Chromium and diamond
• Coating application process: Electrochemical deposition
• Coating structure: Chromium coating with diamond (C)
• Hardness of coating: 900 - 1200 HV 0.1

In order to improve the wear resistance and tribological properties of the rings, different coatings have been used on running surfaces for many years. Galvanic coatings, thermal coatings and PVD coatings are used.  With demands on the load levels of modern internal combustion engines ever increasing, there is often a need to improve the thermal and/or mechanical load carrying capacity of piston ring coatings beyond early life. The patented coating system "Hard Chromium Matrix with Hard Particles Embedded in the Microcrack Network" meets such requirements for the whole life (thickness) of the coating. The variants resulting from the development effort, namely CKS® (chromium with aluminium oxide ceramic) and GDC® (chromium with microdiamond), have a crack network that extends either part-way or all the way through the thickness of the coating, depending on requirements, and is reinforced with embedded hard particles.   As a refinement of the chrome ceramic coating, the Goetze Diamond Coating (GDC® 50) has proved its excellent wear-resistance in large bore engines. Instead of aluminium oxide particles which are embedded in the micro fissure network of the CKS layer, small diamond particles are used. This is a hard chromium coating reinforced with minute diamond particles embedded in the extremely fine crack network with substructure. Compared to CKS® the coating wear was halved and scuff resistance further improved without significantly increasing cylinder wear.  These diamond particles have both higher wear-resistance and offer the advantage that they turn into carbon at high local temperature peaks. This produces a self-lubricating effect (like graphite inclusions) and hence gives the coating higher scuff resistance.