# Phased Array Ultrasonic Testing of W/EUROFER Functionally Graded Coating

## TL;DR

This paper introduces a reliable phased array ultrasonic testing method for detecting delamination in W/EUROFER graded coatings used in nuclear fusion.

## Contribution

A novel phased array ultrasonic test method for analyzing interface characteristics and detecting delamination in FGM coatings.

## Key findings

- The method reliably detected two interfaces in W/EUROFER FGM coatings without delamination.
- Delamination in large-scale curved samples was accurately identified and verified with cross-sectional images.
- The technique works effectively for both small and large-scale components.

## Abstract

W/EUROFER functionally graded material (FGM) plasma-sprayed coatings are used as a protective layer in nuclear fusion applications. It is vital to develop a non-destructive test method to analyze interface characteristics and detect delamination in coatings. A phased array ultrasonic test method was developed in this work to analyze the coating interface characteristics. Two types of coated samples were tested: first, a W/EUROFER FGM-coated flat small sample, and secondly, a large-scale L-shape 50% W and 50% EUROFER curve-coated sample. The phased array ultrasonic test method reliably detected two separate interfaces in W/EUROFER FGM coating, and no delamination was detected, which was verified by cross-sectional image analysis. Secondly, the phased array ultrasonic test precisely detected delamination created during deposition in a large-scale L-shape 50% W and 50% EUROFER curve coated sample. The accuracy in detecting delamination was verified by cross-sectional images of the interface. The phased array ultrasonic test was found to be a reliable method for detecting delamination in multilayer coatings from small-scale to large-scale curved components.