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Non-destructive evaluation of the mechanical behaviour of TiN-coated steels by laser-induced ultrasonic surface waves

: Schneider, D.; Ollendorf, H.; Schwarz, T.


Applied physics. A 61 (1995), S.277-284
ISSN: 0340-3793
ISSN: 0721-7250
ISSN: 0947-8396
Fraunhofer IWS ()
acoustic emission; acoustic surface wave; adhesion test; akustische Emission; akustische Oberflächenwelle; Dünnschichtmeßtechnik; E-Modul; Kratztest; non-destructive testing; photoacoustic test method for thin films; photoakustische Dünnschichtmeßtechnik; Schichthaftung; scratch test; thin film characterisation; TiN-film; TiN-Schicht; Weibull statistic; Weibull-Statistik; Young's modulus; zerstörungsfreie Prüfung

Measuring the propagation velocity of ultrasonic surface waves has been used to determine the Young's modulus of TiN films on steel. Wide-band surface wave im- pulses are generated by a pulsed nitrogen laser and detected by a piezoelectric PVDF-foil transducer. A spectrum of the surface wave phase velocity is obtained from the Fourier transformation of the surface wave signals. The TiN films were deposited after different pre-sputtering times with argon ions to vary the adhesion on the steel substrate. The adhesion behaviour of the films were investigated with the scratch tester. A correlation was found between the Young's modulus of the film material and the acoustic emission activity in the scratch test, which has been shown to be a suitable measure for the adhesion.