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5354 |
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Wednesday, June 07, 2017, Hall 27 12:10 PM Ceramic Coatings |
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The influence of grain size on the mechanical properties of plasma sprayed zirconia coatings |
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Pawel Sokolowski* / Wroclaw University of Science and Technology, Poland Leszek Latka/ Wroclaw University of Science and Technology, Poland Monika Michalak/ Wroclaw University of Science and Technology, Poland Radek Musalek/ Institute of Plasma Physics, Czech Republic |
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One of the trends in the coating industry is the production of finely grained coatings. In the case of plasma spraying this aim was achieved by the application of liquid feedstocks. The studies were performed in order to analyze and understand the effect of grain-size of the coatings produced by plasma spraying on their mechanical properties. The coatings were deposited by Powder Plasma Spraying (PPS) and Suspension Plasma Spraying (SPS) methods using 8 wt.% of Y2O3 stabilized zirconia powder (Oerlikon Metco 204NS). In the case of conventional PPS, the coarse and as-produced powder with the particle diameter of dv50L40µm was used. For the purpose of SPS, the powder was milled by high-energy ball milling. Three kinds of powders having various particles size were produced and sprayed: (i) submicrometer-sized powder dv50L1µm, (ii) and submicrometer-sized powder dv50L0.5µm (iii) and nano-sized powder with dv50L100nm. All feedstock materials were deposited by SG-100 plasma torch with radial injection. Then, the studies of mechanical properties were performed. The adhesion and cohesion of coatings were determined by the use of the tensile strength test and scratch test, respectively. Youngs modulus (E) and hardness (H) were determined by the instrumented indentation technique (IIT). The evolution of failure during loading was analyzed by in-situ SEM bending test. |