Cavitation is one of the most serious problems that affect hydraulic systems and components, mainly power turbines. Welding deposits have been traditionally used to protect components from cavitation damage. Since the protection process is normally associated to maintenance repairs (welding overlay), there are some difficulties related to weld distortion and residual stresses as well as some economic problems regarding to process efficiency and time. Thermal spraying has been recently tested as an alternative to welding in such applications. Some of the materials tested have been proved to be ineffective or inappropriate due to several causes like poor adhesion or mechanical damage. This work refers to a study of wear resistant coatings applied by thermal spraying and welding for cavitation resistance applications. The coatings were applied by High Velocity Oxygen Fuel (HVOF) and Flame Spraying and by Shielded Metal Arc Welding (SMAW). Hardness, roughness as well as cavitation resistance characteristics of the coatings were evaluated. The results show that the obtained coatings are promising for protection in cavitation resistance applications.

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