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Tuesday, June 03, 2008, Auditorium 2 4:15 PM Junior Session This session will deal with different topics, most promising young talents, both from industry and universities will report shortly about their work. This session is accompanied by a special poster exposition. All visitors of this session are allowed to elect their favorite contribution, the winner will be anounced on the awards banquet |
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HVOF sprayed TiC-strengthened Fe-coatings as alternative for conventional carbide materials |
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Thomas Warda* / Surface Engineering Institute
RWTH Aachen University, Germany Kirsten Bobzin / Surface Engineering Institute, Germany Felix Ernst/ Surface Engineering Institute, Germany Katharina Richardt/ Surface Engineering Institute, Germany Guido Reisel/ Sulzer Metco WOKA GmbH, Germany |
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HVOF-sprayed carbide based coatings such as WC/Co or Cr3C2/NiCr are industrially well established for wear and corrosion protection applications. Due to their high carbide content of typically 75 wt.% and more, they are providing a very high hardness and excellent wear resistance. However, at the same time this characteristic is resulting in major difficulties during post-processing steps. Cost-effective machining processes such as turning and milling are usually not applicable and any sprayed oversize has to be reduced by grinding. An alternative concept based on TiC-strengthened Fe-base materials offers promising properties and is already in use for sintering processes. The reduced content of in a ferrous matrix embedded carbides (33 wt.%) can provide improved characteristics for optimal machinability. Depending on the carbon content the Fe-base material can additionally offer a temperable matrix for enhanced wear behaviour. Within this study the sprayability of TiC-strengthened Fe-powders with a gaseous and a liquid fuel driven HVOF-system has been investigated. The resulting coatings have been analysed with respect to microstructure, hardness and phase composition and compared to sintered reference materials. Furthermore the Fe/TiC-coatings have been heat treated to proof the retained temperability of the Fe-matrix after thermal spray processing. Currently the machinability and the corrosion and wear resistance of the sprayed coatings are investigated. |