Tensile Analysis of Plasma Spray Coating Material by Classification of AE Signals

J. Ocean Eng. Technol. 2001;15(4):60-65.

K. ONO

Acoustic Emission 파형분류에 의한 플라즈마 용사 코팅재의 인장해석

김귀식,오명범

제주대학교 기계공학과,제주대학교 기계공학과,UCLA 재료공하과

Keywords: Plasma spray, Ceramic coating layer, Acoustic emission waveform, Tensile testing, Power spectrum analysis

핵심용어: 플라즈마 용사, 세라믹 코팅피막, 음향방출파형, 인장시험, 주파수해석

Abstract

Thermal spray coating is formed by a process in which melted particles flying with high speed towards substrate, then crash and spread on the substrate surface cooled and solidified in a very short time, Stacking of the particles makes coating. In this study, the exfoliation of $Al_2$O$_3$ and Ni-4.5wt.%Al thermally sprayed coating which were deposited by an atmospheric plasma spray apparatus are investigated using an AE method. A tensile test is conducted on notch specimens in a stress range below the elastic limit of substrate. The wave forms of AE generated from the three coating specimens can be classified by FFT analysis into two types which low frequency(type I waveform is considered to corresponds exfoliation of coating layers and type II waveform corresponds the plastic deformation of notch tip or the resultant fracture of coating. The fracture of the coating layers can estimate by AE event and amplitude, because AE features increase when the deformation generates.