RESUMO
Molding of nano structures by injection molding leads to special requirements for the tools e.g., wear resistance and as low as possible release forces of the molded components. On the other hand it is not allowed to affect the replication precision. Physical vapor deposition is one of the promising technologies for applying coatings with adapted properties like high hardness, low roughness, low Young's modulus and less adhesion to the plastics melt. Although physical vapor deposition technology allows the deposition of films on micro structures without changing the structure significantly, film deposition on nano structures and small micro structures leads to a relevant change in surface topography. For this reason direct structuring of physical vapor deposition coatings might be beneficial. In this paper structuring was done using a picoseconds ultraviolet laser, Lumera Laser "Rapid," with a master oscillator power amplifier system at 355 nm. Two different coatings were deposited by magnetron sputter ion plating physical vapor deposition technology for laser structuring tests ((Cr, Al)N, (Cr, Al,Si)N). After deposition, the coatings were analyzed by common techniques regarding hardness, Young's modulus and morphology. The structures were analyzed by scanning electron microscopy. The results show a high potential for laser structuring of coatings deposited via physical vapor deposition. Linear structures with sizes between 400 nm and 10microm were realized.
RESUMO
The process of thixoforming, which has been part of many researches during the last decades, combines the advantages of forging and casting for the shaping of metallic components. But due to the high temperatures of semi-solid steel alloys high demands on the tools are requested. To resists the thermal and mechanical loads (wear, friction, thermal and thermomechanical fatigue) protecting thin films are necessary. In this regard crystalline gamma-Al2O3 deposited via Physical Vapour Deposition (PVD) is a promising candidate: It exhibits high thermal stability, high oxidation resistance and high hot hardness. In the present work the application of a (Ti, Al)N/gamma-Al2O3 coating deposited by means of Magnetron Sputter Ion Plating in an industrial coating unit is presented. The coating was analysed by means of Rockwell test, nanoindentation, and Scanning Electron Microscopy (SEM). The coated tool was tested in thixoforging experiments with steel grade X210CrW12 (AlSI D6). The surface of the coated dies was examined with Scanning Electron Microscope (SEM) after 22, 42, 90 and 170 forging cycles.
