Coating system for fluiding components from cast iron under degradation by wear, cavitation and corrosion

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Many mechanical parts are damaged by mechanical and corrosive loads, e.q. applications of pumps in plant constructions and off-shore properties. The resistance against wear (e.q. abrasion, erosion, and cavitation) and corrosion influence often in combination significantly the life span or the efficiency of such components.The optimisation of the current properties leads often to complex structures of the components. That is the reason to use casting as manufacturing technique and for reasons of economy as material lamellar graphit cast iron. To improve the resistance of the components against the degradation expensive steels and special cast materials are used. These materials are difficult to machine and lead to high manufacturing costs. High developed surfacing technologies have the potential to improve the capacity of components to withstand the loads through economic coatings and to use low cost base materials. The development of such coatings is carried out by experiments and experiences. For choosing coating systems for a defined loading combination the relation between mechanical-technological properties of the coatings and the properties under combined wear, erosion, cavitation and corrosion loading is still not sufficiently investigated.Primary aim of this proposal is the development of a coating system that improves the resistance of components of cast iron against the combined load (erosion, cavitation, corrosion). As coating materials for surfacing (plasma transferred arc surfacing) copper based materials and duplex steel are planned. A combination of welded coatings with thermal sprayed coatings shall be investigated in addition. The development of the coating needs investigation of the basic demands of surfacing cast iron and the influence of the mechanism of the degradation to the resistance of the welded coatings and the combination of welded and sprayed coating against the loads. The basic scientific findings can be transferred to other coating systems of cast iron components and are not limited to this project.