Chrome plating

Abstract: Today the development of clean technologies in all spheres of industrial manufacturing is an essential task, not only for material and metal finishing but also for plasma surface engineering. Among the most critical group of technologies which needs to be replaced by alternative technologies are processes used to produce functional galvanic and decorative coatings. The electroplating of finishes, such as hard chromium, cadmium and nickel in metal finishing is today recognized as a major source of environmental pollution in every country. Therefore wet bath technologies have started to lose favour compared with high performance dry coating methods such as physical vapour deposition (PVD), plasma-assisted chemical vapour deposition, chemical vapour deposition and thermal spraying. Among these techniques, the results obtained with PVD coatings in metal cutting and forming in the last 15 years show the most promising solution of the complicated situation in which galvanic coatings seemed to be technologically and economically irreplaceable. In this paper the general situation in this field is shown. Already today it is possible to replace efficiently some of the galvanic processes in specific cases (e.g. Cr, Ni, Cd, Zn, Au). It is important to point out that PVD is considered to be a technique which can provide not only metallic, but also alloyed and ceramic coatings with a virtually unlimited range of chemical composition and therefore controlled protective, mechanical and wear-resistant properties. Entering into competition with galvanic coatings the manufacturers of PVD coaters were confronted with new requirements: a huge quantity of substrates of the same size, to be chemically and plasma cleaned and then coated at the highest possible deposition rate. For industrial mass production one can therefore use only large PVD batch systems or in-line coaters. The alternative for today's low price galvanic coatings is therefore dry and clean PVD technologies, fully supported by legislation on environmental protection. The economics depend directly on the substrate type and the quantity. The first positive results on the replacement of electrodeposited nickel on aluminium substrates and hard chrome on soft iron are also reported here. A soldering test was made on a sputtered nickel layer. Wear and corrosion tests were performed with iron cores, coated with PVD CrN coating. All tests were made in the Slovenian automotive industry. Results show that for a large number of substrates PVD clean technology is already economically competitive with galvanic coatings.

Abstract: The development of new coating technologies for the wear and corrosion protection of large, high-quality components in the manufacturing industry is becoming more significant, not only from an economic but also from an ecological perspective. In various branches such as aerospace, oil and gas, automotive, papermaking, and others, hard chrome plating (HCP) is a widespread, standard process. However, the implementations of EU directives such as 1999/13/EC (VOC), 2011/65/EU (RoHS), and 2012/19/EU (WEEE) as well as the EU regulation EC 1907/2006 (REACH) to environmental protection, to environmental protection, CO2-reduction, and energy efficiency are leading to considerable market upheavals in the future. In HCP, toxic and carcinogenic hexavalent chromium (Cr6+) is used, which can only be used with authorization after the so-called sunset date in September 2017. Similar applies to the use of nickel in electroplating have been classified as dangerous for the environment and toxic by the World Health Organizati...