Abstract No.:
5284

 Scheduled at:
Wednesday, June 07, 2017, Hall 26 2:00 PM
Wear Protection I


 Title:
Hot-gas corrosion-erosion resistance by thermally-sprayed pseudo-alloys

 Authors:
Rico Drehmann / Chemnitz University of Technology, Germany
Hanna Pokhmurska / Institute of Materials Science and Engineering (IWW), Technische Universität Chemnitz, Germany
Ralf Winkelmann*/ Brandenburgische Technische Universität Cottbus-Senftenberg, Germany

 Abstract:
A key parameter influencing wear resistance is the geometry of the abrasive particles. The equivalent diameter of the particles that primarily cause the wear protection effect should be larger than the grooving trace of the abrasive. A further demand is a uniform and dense distribution of the particles in the matrix. Both requirements can only partially be achieved with hard phases. A different strategy to provide a high wear resistance is the use of pseudo alloys. One possibility for their production is a thermo-mechanical treatment of conventionally sprayed coatings. An alternative technology has been developed. Hard material particles are kinetically charged and fired into the heated spray coating. They are fixed in the layer to assume the primary wear protection. The thermal energy supports reactions between the substrate and the sprayed layer, thus improving adhesion. The reproducible sprayed layers emerged as pseudo alloys. A positive result of the incorporation of ceramic hard materials in the spray layer is the occurrence of compressive stresses in the coating. Parameter studies led to optimal values, the wear rate being a criterion of optimization. The jet erosion wear tests were performed at temperatures up to 750 °C and input speeds of 37.5 m/s. As an abrasive, a +150-212 µm quartz sand was used. 16Mo3 steel served as a reference material. The Al-based alloys were used as coating material. In the transition region to the substrate, a microstructure with multi-phase Fe-Al alloys has been formed. The alloying elements of the spray additive material influence the phase formation significantly. Analyzes of the worn surfaces confirm a good bonding of the embedded hard particles, resulting in increased wear resistance. Metallographic tests served to explain the measured wear rates.

<= go back