Influence of SiC Addition on Mechanical Behavior of Thermal Barriers with the Aid of Acoustic Emission

David Jeronimo Busquets,Maria Dolores Salvador,Amparo Borrell,Carlos Bloem

doi:10.3390/jcs5010016

Abstract

The improvement of high temperature materials with lower heat transfer coefficients lead to the development of thermal barrier coatings (TBCs). One of the most widely used materials for thermal barrier coatings is Y2O3 stabilized ZrO2 (Y-TZP) because of its excellent shock resistance, low thermal conductivity, and relatively high coefficient of thermal expansion. The aim of this work is to study the TBCs mechanical behavior with the addition of SiC into the suspension of Y-TZP/Al2O3 by acoustic emission (AE). Additionally, a microstructural analysis and a finite elements model were carried out in order to compare results. The coatings were made by suspension plasma spray (SPS) on metal plates of 70 × 12 × 2 mm3. An intermetallic was deposited as a bond coating, followed by a coating of Y-TZP/Al2O3 with and without 15 wt.% SiC, with thicknesses between 87 and 161 μm. The AE becomes a fundamental tool in the study of the mechanical behavior of thermal barriers. The use of wavelet transforms streamlines the study and analysis of recorded sound spectra. The crack generation arises at very low stress levels.

Highlights

Nowadays, the world is clamoring for more efficient and eco-friendly machines, resulting in more efforts toward achieving that goal
Results and Discussion study of the accumulated energy; the amount of energy released in each event; and elements method, andMHz, a study of failureper mode frequencies patterns
The results divided into different categories: a microstructural the number of acoustic events. These results will be substantiated with ancharacterization; analysis of finite were done in order to recognize machine, base metal, base metal, and anchor layer into noisea subsequent analysis of the acoustic emission events that, in turn, was subdivided elements method, and a study of failure mode frequencies patterns

Summary

Introduction

The world is clamoring for more efficient and eco-friendly machines, resulting in more efforts toward achieving that goal. The mainstream way is to increase the pressure or temperature on engines and thermomechanical machines. It is common to raise inlet air temperature, increasing the efficiency of the process described by Kristen et al [1], but it entails development of more heat resistant materials or better thermal insulators. Many studies have been done on ceramic coatings because it has a double function. These are thermal insulation, which reduces the components’ temperature, and protection improvement, which reduces corrosion. These materials are called thermal barrier coatings (TBCs)

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Conclusion