Advanced Diamond Coatings for Mechanical Seals

摘要

Since 2007 the hot filament CVD-technology for crystalline diamond thin-film coatings has found its way into the mechanical seal market. Meanwhile this new technology has proved successful in hundreds of applications in a wide range of mechanical seal applications. The reliability and lifetime of mechanical seals was enhanced by factors with diamond coated faces under poor lubrication conditions or in applications with abrasive or chemical aggressive medium. Prior to field applications screening tests by means of a statistical test plan had been carried out in order to find the best ceramic-diamond-system for seal face applications with regard to friction, wear, adhesion, and seal face flatness. Input factors were the substrate itself, the polishing and cleaning process of the substrate, the pre-coating technology, the diamond thickness, the diamond grain size, the grain orientation, the electrical conductivity and the filament process itself. In total 58 different diamond systems with more than 600 individual tests were carried out to find the best diamond system.