Investigation of PVD arc coatings on polyamide fabrics

In contrast to conventional metallisation procedures for textile fibres and fabrics, physical vapour deposition (PVD) technologies allow the production of a defined structure of thin films on most fabric surfaces. This permits many new applications, especially for so-called technical textiles. The generation of properties such as supreme anti-static; electrical conductivity; shielding against electromagnetic radiation, protection against heat rays, chemical resistance, bacterial contamination, increased thermal stability and so on are only some examples. In the paper, initial results for coatings on polyamide fabrics are described. The experimental basis was an industrial PVD coating device of the HTC 1000/4 ABS™-type. Coating was performed in the arc deposition mode. Titanium and zirconium cathodes served as deposition materials. Nitrogen and acetylene were chosen for reactive processing. The aim of the study was to investigate some relevant correlations between the surface structures and functionalities of PVD-coated fabrics and the main process parameters. In particular, tribological and electrical properties were considered. Depending on the evaporation conditions, reactive metal deposition induces chemical and textural changes at the substrate surface due to an etching process. Higher reactive gas concentration leads to a more drastic recombination of the polymer surface and results in a fibroid fibre structure. Furthermore, reactive metal deposition leads to a better layer adhesion than a non-reactive metal deposition.