R&D activities in the field of surface engineering are conducted in three areas: thermal sprayed (TS), plasma transferred arc (PTA) welded and physical vapour deposited (PVD) wear resistant coatings. In the field of TS coatings, the study is aimed at the production of composite coatings based on recycled hardmetal powders and commercial Fe-based self-fluxing alloy powders, in PTA welding – at the production of thick metal-matrix composite hardfacings, based on Fe- and Ni-based commercial spray powders and hardmetal/cermet reinforcements. Potential areas of application of coatings are the following cost-sensitive areas like mining, energy production, road building, agriculture, etc. Thin hard PVD coatings (mono-, multilayer and composite coatings of TiN, TiAIN, AlTiN; nanocoating nACo, etc.) and different coating systems (hardmetal + coatings, high speed steel + coatings, nitrided steel + coatings) were studied. To extend the application areas of thin hard coatings, the duplex coatings and duplex treatments (self-lubricated films on PVD coatings, laser hardening of PVD coated surfaces) were investigated. As a result of the studies, the principles for coatings selection under different operation conditions are formulated.
1. European Technology Platforms on Advanced Engineering Materials and Technologies (EuMaT): http://eumat.eu/ (03.05.2011).
2. Mellor, B. G. Surface coatings for protection against wear. Woodhead publishing, Cambridge, UK, 2006.
3. Bach, F. W. Laarmann, A. and Wenz, T. Modern Surface Technology. Wiley, Weinheim, 2004.
4. Kulu, P., Käerdi, H. and Mikli, V. Retreatment of used hardmetals. In Proc. TMS 2002 Recycling and Waste Treatment in Mineral and Metal Processing: Technical and Economic Aspects. Lulea, 2002, vol. 1, 139–146.
5. Kulu, P. and Zimakov, S. Wear resistance of thermal sprayed coatings on the base of recycled hardmetal. surface coat. technol. 2000, 130, 46–51.
6. Surzhenkov, A. Duplex treatment of Steel Surface. PhD Thesis, Tallinn University of Technology, TUT Press, 2011.
7. Deuis, R. L., Yellup, M. and Subramanian, C. Metal-matrix composite coatings by PTA surfacing. Composites Sci. Technol. 1998, 58, 299–309.
8. Branagan, D. J., Marshall, M. C. and Meacham, B. E. High toughness high hardness iron based PTAW weld materials. Mater. Sci. Eng. 2006, A 428, 116–123.
9. Recycling and reuse of scrap metals. Nuclear Energy Agency. OECD, Paris, 1996.
10. Zikin, A., Ilo, S., Kulu, P., Hussainova, I., Katsich, C. and Badisch, E. Plasma transferred arc hardfacing of recycled hardmetal reinforced nickel-matrix surface composites. Mater. Sci. (Medžiagotyra), 2012, 18, 12–17.
11. Katsich, C. and Badisch, E. Effect of carbide degradation in a Ni-based hardfacing under abrasive and combined impact/abrasive conditions. Surface Coat. Technol., 2011, 206, 1062–1068.
12. Nurminen, J., Nökki, J. and Vuoristo, P. Microstructure and properties of hard and wear resistant MMC coatings deposited by laser cladding. Int. J. Refract. Met. Hard Mater., 2009, 27, 472–478.
13. Zikin, A., Hussainova, I., Katsich, C., Badisch, E. and Tomastik, C. Advanced chromium carbide-based hardfacings. Forthcoming.
14. Kulu, P. Selection of powder coatings for extreme erosion wear conditions. Adv. Eng. Mater., 2002, 4, 392–397.
15. Kleis, I. and Kulu, P. Solid Particle Erosion: Occurrence, Prediction and Control. Springer, London, 2008.
16. Gregor, A. Hard PVD Coatings for Tooling. PhD Thesis, Tallinn University of Technology, TUT Press, 2010.
17. Zum Gahr, K.-H. Microstructure and Wear of Materials. Tribology Series 10, Elsevier, Amsterdam, 1987.18. Feasibility Study for an Estonian Materials Technology Programme. http://www.mkm.ee/ innovatsiooniuuringud/ (31.05.2012).