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| Abstract No.: |
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Scheduled at:
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Tuesday, June 03, 2008, Room 08 9:30 AM
Fe-based Materials 1
Due to the worldwide rise of material costs Fe-based materials are becoming more and more a suitable alternative to established hard phase coatings
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| Title: |
Thermally sprayed coatings with stochastic microstructures for thermomechanically high stressed surfaces
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| Authors: |
Bert Drößler* / Institute of Materials Science, Leibniz Universität Hannover, Germany
Friedrich-Wilhelm Bach / Institute of Materials Science, Leibniz Universität Hannover, Germany
Kai Möhwald/ Institute of Materials Science, Leibniz Universität Hannover, Germany
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| Abstract: |
The experimental work described in this paper is carried out in the scope of the DFG research group 576 ”Microstructuring of thermomechanically high stressed surfaces“.
In practise, thermal spray metal and ceramic coatings are already used in the automotive sector, amongst others for creating percentage contact areas and improving lubricant holding/conditioning. At present only honed thermal spray coatings have been used without further microstructure advancements for optimized lubricant retention and distribution. There is a high potential in this field regarding the design and creation of defined functional structures though. One approach is the development of a coating process in which the coating surface topology can be controlled by systematic influencing the nap/pore structure creation (in regards to distribution, geometry, density). Additionally, lamellar coating fractures can scale off and hereby open pores in deeper layers as naps, thus generating the same surface microstructure again during the parts’ life cycle.
In the described ongoing research project plasma spray processes are analyzed for their usability to reliably generate evenly distributed porosity patterns and surface microstructures. Here, key process parameters are to be ascertained which allow systematic control of porosity, especially in terms of responsiveness and reproducibility. In this connotation the characteristics of coating porosity (open/closed porosity, pore shape, distribution) and mechanical coating properties combined with machining/slide wear have to be assessed for different tribological matchings. So far, various parameters like spray materials and composition, fractions and particle size distributions, spray distances and plasma parameters were varied in the experiments. The effect on coating porosity and tribological behavior were examined by metallographic analyzes, surface topology characterizations and tribological tests. The results will be used for the design of inner bore coating processes in prospective work packages.
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