Coatings, Vol. 15, Pages 1078: A Study of the Properties of Two-Layer Coatings Based on TiO2-Cr2O3/Ta

Coatings doi: 10.3390/coatings15091078

Authors:
Bauyrzhan Rakhadilov
Zhangabay Turar
Dauir Kakimzhanov
Dastan Buitkenov

In this work, a comparative study of the corrosion resistance and microstructural characteristics of oxide coatings based on TiO2 and TiO2 + Cr2 + Cr2O3 both deposited onto and without a tantalum sublayer has been carried out. The coatings were formed through thermal spraying, and their corrosion behaviour was evaluated through potentiodynamic polarisation in 3.5% NaCl solution using a potentiostat–galvanostat in a three-electrode cell. The TiO2 + Cr2O3 composite coating, applied with a tantalum sublayer, had the lowest corrosion current density and the most positive corrosion potential, indicating its high corrosion resistance. The morphology and elemental composition of the coatings were analysed using scanning electron microscopy (SEM) and energy-dispersive analysis (EDX). The microstructural analysis revealed that the coatings with Cr2O3 added were characterised by an increased density, a more uniform phase distribution, and improved adhesion to the substrate. The obtained results confirm that combined TiO2 + Cr2O3 coatings with a tantalum sublayer are promising for use in aggressive environments due to their high corrosion resistance and structural stability.

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