Application of wear-resistant PACVD coatings in aluminium diecasting: economical and ecological aspects

One of the major manufacturing techniques for aluminium precision parts is the pressure diecasting process. However, nowadays the state of the art inv olves the application of large amounts of lubricants. Their side effects in clude a decrease in the surface quality of the cast as well as ecological r isks. The deposition of wear-resistant coatings provides a means of minimis ing the use of lubricants while at the same time increasing the lifetime of the diecasting tools. In this study, nitrides, carbides and borides of tit anium were synthesized with regard to their composition, structure, hardnes s, adhesion, wetting behaviour and corrosion resistance to aluminium melt. The coated cores were exposed to diecasting praxis tests under tightened-up conditions, reducing the amount of lubricants. The optimal PACVD coating l ed to an increase in lifetime by a factor of 300 compared to an uncoated to ol. A reduction of 97% of the original amount of lubricants could be achiev ed. (C) 1999 Elsevier Science S.A. All rights reserved.