Abstract. The state of laser processing in surface materials modification in Poland is reported, based on own experience, coworkers and coauthors results, as well the literature review. The curriculum concerning historical development of lasers and laser technology in Poland, laser-matter interaction, as well basis of different laser techniques applied in materials surface engineering (solid state hardening, melting, alloying, cladding, ablation, shot peening, cleaning and texturing) are reviewed, and compared with results of coauthors, as well with a wide range of Polish authors papers. Finally, it is concluded that overall state of research on laser application in surface engineering in Poland is well developed and still growing industrial application is observed.
Abstract. The mechanical and tribological behavior of physical vapor deposited coatings on soft substrate materials gains increasing interest due to economical and environmental aspects -e.g. substitution of steels by light-weight metals or polymers in transport vehicles. Nevertheless, such soft materials require surface protection against wear in tribological contacts. Single layer hard coatings deposited at room temperature are brittle with a relatively poor adhesion. Therefore, they should be better substituted by tough multilayer coatings of soft-hard material combinations. However, the mechanics of such multilayer coatings with several 10 nm thick bilayer periods is difficult and yet not well described. The presented work tries to fill the gap of knowledge by focusing both on mechanical investigations of hardness, adhesion, and wear and on microscopic elucidation of deformation mechanisms. In the paper 1 µm thick Ti/TiN multilayer stacks were deposited by magnetron sputtering on soft austenitic steel substrates at room temperature to prevent distortion of functional components in future applications. High hardness was found for 8 and 16 bilayer films with modulation ratio Ti:TiN = 1:2 and 1:4. This was attributed (with use of transmission electron microscopy) to stopping the crack propagation in thin Ti layers of the multilayer systems by shear deformation combined with different fracture mechanisms in comparison with that for the TiN single layers (edge cracks at the border of the contact area and ring cracks outside, respectively).
Functionalization of surfaces is an important task for nanotechnology to add specially designed physico-chemical properties to materials. Besides chemical modification of surfaces, physical adaptations gain increasing interest. Thus, understanding the influences of film deposition on surface topography formation is the basis for future developments. For physical or chemical vapour deposited (PVD, CVD) films, structure zone models were developed, clearly showing the influences of temperature and vapour energy and, thus, surface and bulk diffusion on film structures based on four different structure zones. Generally, similar zones are also found in PVD coatings on polymeric substrates; However, due to restrictions in coating temperatures due to the thermal resistance of most polymers, the coating temperature is restricted to mostly 50˚C, excluding thermal activation of at least surface diffusion of inorganic materials (metals and their nitrides, oxides, carbides, etc.) and resulting in columnar growth with dome-shaped column tops. Additionally, the high difference in mechanical properties between "stiff" inorganic coatings and "flexible" polymers implicates stress-induced growth phenomena, resulting in wrinkling, cracking and finally the formation of a superseding structure, depending on substrate and film materials and the vapour energy of the deposition method.
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