Technical Diagnostics and Non-Destructive Testing, 2025, №01

2025 №01 (01)

DOI of Article 10.37434/tdnk2025.01.02

2025 №01 (03)

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"Tekhnichna Diahnostyka ta Neruinivnyi Kontrol" (Technical Diagnostics and Non-Destructive Testing) #1, 2025, pp. 10-15

Evaluation of microscopic defects in hydraulic turbine blade coatings

C.A. Tugui¹, A. Savin², V.M. Uchanin³

¹Materials Processing Technologies and Equipment Department, Gheorghe Asachi Technical University, Iași, Romania. E-mail: tzugui.andrei@yahoo.com
²Nondestructive Testing Department, National Institute of Research and Development for Technical Physics, Iasi, Romania. E-mail: asavin@phys-iasi.ro
³G.V. Karpenko Physico-Mechanical Institute of the NAS of Ukraine NASU. 5 Naukova str., 79060, Lviv, Ukraine. E-mail: vuchanin@gmail.com

Hydro-abrasive wear is a major problem for the efficiency and durability of Francis turbines, widely used in hydroelectric power plants due to their ability to transform hydraulic energy into sustainable electricity. Constantly exposed to abrasive particles in water, turbine components are subjected to intense stresses, which lead to progressive deterioration and shortening of their lifespan. In this context, scanning electron microscopy (SEM) analysis becomes an essential tool for the evaluation and understanding of microscopic defects induced by hydro-abrasive wear. SEM allows for the detailed characterization of the affected surfaces and the identification of the types of damage, thus providing fundamental data for the optimization and selection of abrasion-resistant materials. Thermal spray of materials, such as Metco 71VF-NS (WC12Co) are an important solution in combating wear, being renowned for their increased hardness and strength. These sprayed layers not only protect the turbines from the effects of hydro-abrasive wear, but also contribute to the overall efficiency of the system by reducing the frequency of repairs and maintenance. Thus, in the context of renewable energy, where reliability and durability of equipment are essential, the use of advanced materials to protect Francis turbines represents a crucial step towards sustainable and efficient production of electricity based on hydraulic resources. 22 Ref., 2 Tabl., 5 Fig.
Keywords: thermal spraying, coatings, SEM, structure, thickness, porosity

Received: 27.11.2024
Received in revised form: 21.02.2025
Accepted: 22.03.2025

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