Location

Snowbird, UT, USA

Start Date

1-1-1999 12:00 AM

Description

Since ceramic/metal joints currently play an important role of the structural parts for applications in electrical, electronic or aerospace industries, techniques must be developed for evaluating the integrity of these joints. Such techniques as collimated X-ray beam radiography [1], indentation fracture, and laser speckle imaging have been developed with limited success. No truly nondestructive techniques for evaluating joint strength have been established to date. If a conventional C-scan mode apparatus could be applied directly for detecting a defect such as a delamination on a joint interface, it might be an attractive solution in terms of visualizing the defect as a first step in the evaluation. The shape of the standard specimen of the ceramic/metal joint is essentially a rectangular bar. When the C-scan mode apparatus is used to visualize the jointed interface, an acoustic wave is required to be incident from the ceramic side of the specimen. When considering the attenuation of an ultrasonic wave in the frequency range from 10 to 100 MHz and the thickness of the ceramic portion of the specimen, the wave may not reach the interface, or the wave reflected from the interface may not be detected. When using frequencies lower than 10 MHz, the interface may be imaged, but with limited resolution. Moreover, the contrast may be poor because of water diffusing into the crack in the surface of the specimen. When a conventional A-mode apparatus such as a digital oscilloscope is used to obtain quantitative data, reflected waveforms might be collected. However, the data might not be good enough to analyze details of a defect, such as caused by a fracturing process. Recent studies have shown that delaminations at a ceramic/metal joint, such as a Si3N4/Cu/Steel joint, originate along the periphery of the interface [2].

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

18B

Chapter

Chapter 5: Engineered Materials

Section

Coatings, Interfaces, and Bonds

Pages

1479-1485

DOI

10.1007/978-1-4615-4791-4_190

Language

en

File Format

application/pdf

Share

COinS
 
Jan 1st, 12:00 AM

Detection of Delaminations Located at Ceramic/Metal Jointed Interface by Scanning Acoustic Microscopy

Snowbird, UT, USA

Since ceramic/metal joints currently play an important role of the structural parts for applications in electrical, electronic or aerospace industries, techniques must be developed for evaluating the integrity of these joints. Such techniques as collimated X-ray beam radiography [1], indentation fracture, and laser speckle imaging have been developed with limited success. No truly nondestructive techniques for evaluating joint strength have been established to date. If a conventional C-scan mode apparatus could be applied directly for detecting a defect such as a delamination on a joint interface, it might be an attractive solution in terms of visualizing the defect as a first step in the evaluation. The shape of the standard specimen of the ceramic/metal joint is essentially a rectangular bar. When the C-scan mode apparatus is used to visualize the jointed interface, an acoustic wave is required to be incident from the ceramic side of the specimen. When considering the attenuation of an ultrasonic wave in the frequency range from 10 to 100 MHz and the thickness of the ceramic portion of the specimen, the wave may not reach the interface, or the wave reflected from the interface may not be detected. When using frequencies lower than 10 MHz, the interface may be imaged, but with limited resolution. Moreover, the contrast may be poor because of water diffusing into the crack in the surface of the specimen. When a conventional A-mode apparatus such as a digital oscilloscope is used to obtain quantitative data, reflected waveforms might be collected. However, the data might not be good enough to analyze details of a defect, such as caused by a fracturing process. Recent studies have shown that delaminations at a ceramic/metal joint, such as a Si3N4/Cu/Steel joint, originate along the periphery of the interface [2].