Newly developed chromium-free organic-inorganic composite coated steel sheet with excellent corrosion resistance

From the point of view of ecology, there has been a trend of measurable advances in coated steel sheets for electrical appliances. For further advancement, completely hexavalent chromium-free coated products need to be developed. Despite the large amount of research of chromium free coating being carried out for many years, there have never been products that could provide excellent corrosion protection with a low cost treatment until recently. Recently, in response to the increasing demands for ecological products, new chromium-free coated steel sheets were industrialized independently by each of the six major steel companies in Japan in 1998. Those products were adopted for chassis and cases of audio-visual and office equipment. Features and practical characteristics of one of the new products, GEO-FREONTIER COAT (GF) developed by NKK Corp. are to be presented.