Yttria-stabilized zirconia thin films via MOCVD for thermal barrier and protective applications in injection moldingDonnerstag (06.07.2017) 17:00 - 17:20 Uhr Bestandteil von:
Steel tools, which are used in industrial high-throughput processes like injection molding, are susceptible for wear and corrosion due to rapid cyclic temperature and pressure fluctuation as well as the use of abrasive polymers. For the protection of tool surfaces high quality ceramic thin films can be applied by metal-organic chemical vapor deposition (MOCVD). In addition to protective properties ceramic materials like yttria-stabilized zirconia (YSZ) are able to thermally insulate tool surfaces providing a more precise temperature regulation with intent to avoid the formation of surface flaws, e.g. weld lines, in the later plastic parts. At the same time it enables the shortening of cycle times as well as the decrease of energy demands during the molding process.
In this work we demonstrate the fabrication of zirconia based thin films and multilayer systems on steel tools with complex 3D surfaces via MOCVD using metal acetylacetonates as precursor materials. Coating development was carried out by measuring the film thicknesses at different parameter settings. The usage of autonomous liquid flow controllers enables the formation of multilayer systems as well as the control of crystallinity by addition of different dopants to the material. Alternating crystalline and amorphous layers lead to an increase in flexibility and diminishment of local stress in the joint material. For process development substrates were engineered according to tool geometry containing typical cavities and defined cracks aspect ratios up to 1:60. That application enables the proof of conformity and the verification of homogeneous film thickness distribution. Exploitation of these results offers the coating of tools, which are tested regarding their desired properties by industrial project partners under production conditions.