Magnetron Sputtered Ti-Basis Hard Material Coatings on Thermoplastic Polymers for Applications in Particle Sensitive Environments

Even under demanding environments, like clean rooms, polymers are already used in different-ranges of applications. The wear and particle generation within a specific particle size even under-mechanical stress is a limiting factor. So it was the aim to develop an innovative material-concept, that enables to apply a thermoplastic polymer coated with a thin hard material (thickness-up to 2.5 gm), which also prevents for electrostatical discharges and is usable for complex-bodies. Therefore it was necessary to improve the wear resistance and the adherence between the-polymer and the coating. To take also economic aspects into consideration a two step production-process sequence was required, consisting of the injection moulding process and then the plasma-deposition process including a plasma pre-treatment. In this investigation, poly(butyleneterephthalate)-(PBT) and poly(amide) 6.6 (PA) and polycarbonate (PC) were chosen as substrate-material. The coating materials used, which were mainly deposited by Magnetron Sputter Ion-Plating (MSIP), were on titanium basis (Ti-N). To get detailed chemical information about the-coatings and the interfacial region they were analyzed by X-Ray Photoelectron Spectroscopy-(XPS), additionally Secondary Ion Mass Spectrometry (SIMS) experiments were carried out to-confirm the results. The process parameter’s influence on the microstructure, which extend from-amorphous to columnar (crystalline), and the film thickness were analyzed by SEM. It will be-shown and discussed, that it is possible to improve the coating’s adherence by plasmapretreatment-as well as to reduce the particle generation after a suitable etching and coating process.