Fatigue behaviour of Plasma Sprayed Titania and Chromia Coatings

Angelos Koutsomichalis,Michalis Vardavoulias,Nikolaos Vaxevanidis,Antonios Lontos,George Loukas,S Pantelakis,K Tserpes,G Lampeas

doi:10.1051/matecconf/202134902009

Abstract

Cr2O3 and TiO2 powders were deposited by atmospheric plasma spray (APS) on steel substrates. Microstructural analysis of the coatings showed typical lamellar structure with good coating quality. Fatigue strength was studied by using cyclic testing (measuring with an inhouse-built apparatus the strength of the coated systems under a wide range of impact cycles) and static loading tests (Vickers tests standards with 600N and 1500N) measuring the adhesion properties of the coatings. In low cycles (1x103) Titania coatings exhibited better strength, while at intermediate (4.5x105) and high (1x106) number of impact cycles, both Chromia and Titania coatings exhibited quite similar strength characteristics. At low impact force the thickness of the coatings plays critical role with better performance obtained by Chromia coatings. During static loading both coatings exhibited similar characteristics at the crater diameter but with larger crater depth for Titania. Chromia coatings exhibited higher strength resistance than Titania coatings with better mechanical properties and coating structure.

Highlights

The coating technology has the advantage of combining two dissimilar materials to improve, in a synergistic way, the performance of the whole
One of the most common deposition techniques for thick coatings, is characterized by a set of unique features, such as the wide range of materials, homogeneous coatings, fine microstructures, high deposition rate and a process being performed in any conceivable environment [1, 2].The purpose of this study is to study the fatigue properties of Cr2O3 (Chromia) and TiO2 (Titania) coatings
This paper focuses on the fatigue behaviour of chromia and titania plasma sprayed coatings, introducing a unique fatigue tester and seeks to address the relation of coating application and structure on their fatigue behaviour in an effort to elucidate prior findings

Summary

Introduction

The coating technology has the advantage of combining two dissimilar materials to improve, in a synergistic way, the performance of the whole. A rather limited number of research studies have been carried out on the fatigue behaviour of plasma sprayed coated specimens with conflicting findings relative to the https://doi.org/10.10 51/matecconf /202134902009 influence of coatings on the fatigue life either enhancement [8,9] or debit [10,11]. Some studies investigate the effect of substrate preparation prior to coating deposition, such as shot peening or grit blasting, which are considered as residual stress contributors mitigating fatigue debits incurred by coating application [12] or attempt to isolate the coating’s influence on fatigue life [13]

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