Facing EU environmental limits on traditional plating, C.T.I. breaks through with a near-diamond Diamond-Like Carbon (DLC) coating — high hardness, low friction, corrosion- and wear-resistant with high thermal conductivity — backed by US and Taiwan patents.
Diamond-Like Carbon (DLC — C.T.I. brand name "Black Diamond") is an amorphous carbon coating with a structure close to diamond. As EU environmental regulations tighten and traditional hexavalent-chromium plating faces limits, C.T.I. breaks through with DLC — giving piston rings a high-hardness, low-friction, corrosion- and wear-resistant, high-thermal-conductivity, eco-friendly surface treatment, backed by US and Taiwan patents.
Diamond-Like Carbon (DLC) is an amorphous carbon material that combines diamond-like (sp³) and graphite-like (sp²) bonds, deposited on the piston-ring substrate by physical vapour deposition (PVD), chemical vapour deposition (CVD) and similar methods. Because its structure is close to diamond, it has both extremely high hardness and extremely low friction — one of the most advanced piston-ring surface treatments available.
1. High hardness: in Vickers testing, C.T.I.'s DLC coating exceeds 2500 Hv0.05 — far harder than ordinary plating, greatly improving wear resistance.
2. Low friction: conventional plated coatings have a friction coefficient of about 0.3–0.4; DLC lowers it to below 0.04, cutting friction losses and improving fuel efficiency under high load and speed.
3. Corrosion resistance: DLC has excellent chemical stability, resisting a wide range of corrosive media.
4. High wear resistance: its outstanding hardness significantly extends ring and engine service life.
5. High thermal conductivity: DLC conducts heat well, quickly transferring piston heat to the cylinder wall.
As EU and other environmental regulations increasingly restrict hexavalent-chromium and similar plating processes, the industry is seeking greener, sustainable alternatives. DLC contains no hazardous heavy metals, has a cleaner process, and surpasses traditional plating in hardness, friction, corrosion resistance and thermal conductivity — an ideal choice for high-performance piston rings.
C.T.I. has a deep research base in DLC (Black Diamond) and leads the world with US patent US 905744B2 and Taiwan patent M300746. These cover the preparation of the coating and the tuning of film performance, giving C.T.I. a strong foundation for high-performance, highly reliable DLC piston rings and surface-treatment services, while meeting its environmental responsibilities.
© C.T.I. Traffic Industries Co., Ltd. Original content by C.T.I. — reproduction, copying or commercial use without permission is prohibited.
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