HVOF and HVAF Coatings of Agglomerated Tungsten Carbide-Cobalt Powders for Water Droplet Erosion Application

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• 作者：F. Tarasi ; M. S. Mahdipoor ; A. Dolatabadi ; M. Medraj…
• 关键词：high ; velocity air fuel thermal spray ; high ; velocity oxy ; fuel thermal spray ; water droplet erosion resistance ; WC ; Co
• 刊名：Journal of Thermal Spray Technology
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：25
• 期：8
• 页码：1711-1723
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Surfaces and Interfaces, Thin Films; Tribology, Corrosion and Coatings; Characterization and Evaluation of Materials; Operating Procedures, Materials Treatment; Analytical Chemistry;
• 出版者：Springer US
• ISSN：1544-1016
• 卷排序：25

文摘

Water droplet erosion (WDE) is a phenomenon caused by impingement of water droplets of several hundred microns to a few millimeters diameter at velocities of hundreds of meters per second on the edges and surfaces of the parts used in such services. The solution to this problem is sought especially for the moving compressor blades in gas turbines and those operating at the low-pressure end of steam turbines. Thermal-sprayed tungsten carbide-based coatings have been the focus of many studies and are industrially accepted for a multitude of wear and erosion resistance applications. In the present work, the microstructure, phase analysis and mechanical properties (micro-hardness and fracture toughness) of WC-Co coatings are studied in relation with their influence on the WDE resistance of such coatings. The coatings are deposited by high-velocity oxygen fuel (HVOF) and high-velocity air fuel (HVAF) processes. The agglomerated tungsten carbide-cobalt powders were in either sintered or non-sintered conditions. The WDE tests were performed using 0.4 mm water droplets at 300 m/s impact velocity. The study shows promising results for this cermet as WDE-resistant coating when the coating can reach its optimum quality using the right thermal spray process and parameters.