Electroplating. Chemical nickel. Dispersion and combination coatings

The uniformity of their thickness is characteristic of chemical-nickel coatings. Their phosphorus content influences their resistance to corrosion and wear. Addition of dispersing agents improves their properties. Another possibility to influence the coating properties is combining chemical-nickel- and PVD coatings. The discussion covers introduction; coating combinations; combination with PVD coatings; dispersion coatings; and higher service life. Chemical nickel precipitation is based on a reduction of the nickel ions to nickel metal in an aqueous process solution. The chemical reaction partners and suppliers of the necessary ions to achieve this are hypo-phosphite ions in the solution that in the course of reaction are oxidized to ortho-phosphite. The coating that is formed is a nickel-phosphorus alloy, the Durni-Coat&reg coating (in short: DNC coating). The DNC coatings differentiate themselves in their mechanical, chemical, and physical properties in part by phosphorus-free electroplated or metallurgically produced nickel. The Durni-Coat coatings that are deposited without external sources of electricity are uniform. The performance of these coatings especially the tribological and corrosion values, are influenced by the phosphorus content that can be 3-14%. For example, Durni-Coat coatings with higher phosphorus content are less wear resistant that those with lower phosphorus content, but in exchange they are more ductile and corrosion resistant.