Ecological process for depositing thin layers with high tribology resistance for reconditioning the hydraulic turbines

Abstract

Abstract Plasma thin-film deposition can be used to refurbish hydraulic turbine assemblies and subassemblies. In the case of reconditioning by the plasma jet deposition method, one or more plasma jet passes may be carried-out over the worn surface until the gaps achieved by the effect of the hydro-abrasive wear are filled with the depositing material. This paper presents the results obtained at the hardness tests of the thin layers deposited by plasma jet with powders based on Nickel and Boron (Deloro 60). Also, the adhesion of the multiple layers to the base material as well as the adhesion between the layers and the defects that appear on its separation surface were studied. The samples were also analysed from the point of view of the chemical composition by EDX probe and structurally by optical and electron microscopy Vickers-type micro-hardness tests were performed to determine the micro-hardness of the base material and the deposited layer. The VEGA II LMH electron microscope (TESCAN) with TAX QX2 EDX module was used to determine the material structure. The samples were obtained by the method of spraying in mesh spray with Ni powder. By this type of deposition, an easy method of obtaining and rectifying the blades of the hydraulic turbines is obtained with aims to harden the turbine’s blades, in order to increase the wear resistance without affecting the corrosion resistance.