Hard chrome plating has been the standard solution for manufacturers for more than six decades to increase the hardness, abrasion resistance and corrosion resistance of various components. Common applications include hydraulic cylinders and pistons, piston pins, valves, rolls, molds, dies, press punches, shafts and rotors for pumps, etc.
However, conventional hard chrome electroplating process known as hex-chrome or chrome (VI) plating generate hexavalent chromium ions which is a known carcinogen. In the European Union, the use of hexavalent chromium is in the process of becoming prohibited.
Several alternative technologies have been developed, among which various thermal spray, PVD and CVD coatings could be mentioned. Known commercial products are Hardide® CVD coatings, Duralar PACVD coatings, InnerArmor plasma spray coatings, Tribond™ PVD and PACVD coatings, etc.
Two Swedish companies, Tribonex and Bodycote have joined forces to bring to the market a new technology – CorroNite™ – that is based on a thermal processing & coating concept (TP&C). CorroNite™ is currently being explored as a promising alternative to hard chrome. Prototype hydraulic rods have been produced and tested in close cooperation with Volvo Construction Equipment and Trelleborg Sealing Solutions within the Strategic Innovation Program for Graphene, SIO Grafen, a joint initiative of Vinnova, Formas and the Swedish Energy Agency. CorroNite™ coated rods have been evaluated together with PFAS free seals and demonstrated excellent performance in terms of endurance and friction behavior, performing similar to hard chrome. CorroNite™ also gives the rods a beautiful dark color and shine!
