Global quality directives have banned use of hexavalent chromates in most applications, replacing them with the weaker trivalent chromium passivates. For fasteners, the organo-mineral topcoats have advanced to provide torque and friction modification, and other benefits.

Authors: Jean-Jacques DUPRAT, CTO COVENTYA Group and Mike KELLY, VP Anti-Corrosion Coatings, COVENTYA USA

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Published in Fastener Tech. International. www.fastenertech.com

Electroless Nickel coatings reinforced with diamond, silicon carbide, boron nitride, or PTFE particles can impart specific wear and lubricity properties to complex surfaces.

Author: Lloyd Ploof, COVENTYA USA

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www.asm-electrolessnickel.com

www.nasf.org

Les revêtements de chrome sont utilisés depuis de nombreuses années pour des applications décoratives ou techniques. Le chrome décoratif repose sur l’élaboration d’un revêtement très mince de 0,1 à 1 µm afin d’obtenir une surface brillante avec une bonne résistance à l’usure et à l’abrasion ainsi qu’une résistance au ternissement.

Auteur: Nicolas Pommier, Chef de Produit Décoration. COVENTYA France

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Chromate based conversion coatings are widely used for the protection of Aluminium and Aluminium alloys. They act as a protective coating against corrosion and serve also as a base for paint adhesion. Toxicological studies have evidenced the hazardous character of hexavalent chromium.

Authors: Lionel Thiery, Technical Manager & Frédéric Raulin, Product Manager for protection segment, and Key Industry Manager for Automotive Industry. COVENTYA France

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www.surfair.com

During the last decade, a technical revolution has occurred in the technology for applying conversion coatings to zinc and zinc alloy deposits. All hexavalent chromates have been banned by the EC and have been generally replaced by trivalent chromium passivates. Despite some similarities, the mechanisms by which these two technologies convert a zinc coated surface are radically different. This paper aims to explain the mechanism of formation of the conversion layer and to describe how the technology is being used throughout the world for industrial applications.

Authors: Jean-Jacques Duprat, CTO of COVENTYA Group and Lionel Thiery, Technical Manager of COVENTYA France

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Für die Überprüfung der Beständigkeit von Korrosionsschutzsystemen ist der neutrale Salzsprühtest nach DIN EN ISO 9227 (alt: DIN 50021-SS) momentan die am meisten verwendete Methode. Die erhaltenen Ergebnisse in „Stunden bis Zink-Korrosion / Grundmaterial-Korrosion“ sind wichtige Indikatoren für die Bewertung und Freigabe dieser Systeme.

Author: Klaus Wojczykowski, COVENTYA Germany

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www.zvo.org
www.galvanotechnik.com/Jahresinhalte
www.galvanotechnik.com/English

Nel lusso la bellezza di un oggetto è percepita come qualità. Gli aspetti estetici assumono un’importanza pari a quella delle prestazioni dei prodotti. Perciò è grande l’attenzione prestata ai trattamenti superfi ciali, che stanno acquisendo anche un’altra valenza: quella della unicità, anche per arginare il fenomeno della contraffazione.

Trattamenti e Finiture, febbraio 2008.
COVENTYA, Precious Metals

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For over 10 years, the substitution of chromate processes on zinc has been one of the driving forces in supply house development laboratories. Passivations based on CrIII seemed to be their accepted replacements. Their development has proceeded over several stages leading up to a programme of optimisation relating to corrosion resistance performance....

Authors : L. Thiery & N. Pommier, COVENTYA France

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