Corrosion and wear protection, high surface hardness and low roughness: piston rods for hydraulic cylinders are among the main products of fluid technology that must meet these requirements. So far, the hydraulic industry has relied on hard chrome coatings to achieve these properties. However, the Cr-VI-containing electrolytes for chromium coatings are harmful to health and their approval requires an extensive approval procedure. At RUBIG, we therefore offer environmentally friendly PACVD and nitriding processes as an alternative.
Environmentally friendly alternatives: Nitriding and PACVD coatings
In a study conducted by RUBIG, nitriding and PACVD coating in particular emerged as suitable alternatives:
Specifically, in the plasma or gas nitriding process, atomic nitrogen is introduced into the surface of the substrate by diffusion, which increases the hardness. (Diffusion is the process by which atoms or molecules propagate in a material.) Hardness-increasing alloying elements such as aluminum, vanadium or chromium are essential for increasing the hardness. The iron nitride layer formed on the surface has a ceramic character and is characterized by a higher corrosion and wear resistance compared to the bare steel surface. In a subsequent process, the surface can be further oxidized to obtain a corrosion-resistant Fe3O4 layer.
With the PACVD technology (Plasma Assisted Chemical Vapor Deposition), coatings such as titanium nitride, titanium boron nitride or DLC (Diamond like carbon) can be deposited. With a layer hardness of regularly 1000 to 1500 HV, layer thicknesses of up to 20 µm and consequently excellent corrosion properties, the DLC layers in combination with a preceding nitration that are particularly suitable for the hydraulic industry. In comparison to hard chrome coatings, these technologies not only provide high [WA1] corrosion and wear resistance, but are also more environmentally friendly and less harmful to health.
Chrome alternatives offer higher corrosion resistance
In the present investigation, both corrosion resistance and tribological behavior of two commercially available chromium coatings were investigated and compared with the nitriding and coating processes developed by RUBIG. The result: The RUBIG alternatives have very good properties in terms of corrosion and wear resistance.
More efficient and more environmentally friendly
The new technologies for surface treatment offer significant advantages for the hydraulic industry. They are not only very powerful, but also more environmentally friendly and safer. The future of the hydraulic industry depends heavily on the implementation of such advanced technologies to meet the increasing demands for efficiency and sustainability.
Are you interested in the technology or the mentioned study? ThenAnnika Wagner is at your disposal.
Everything from a single source
RUBIG is not only a reliable service provider when it comes to the contract treatment of hydraulic components, but also a competent partner in the development of new processes as well as in the construction of the corresponding heat treatment and coating systems.
