Nondestructive Internal Observation of Ceramics Using Electron-Acoustic Microscopy

摘要

An electron-acoustic microscopy (EAM) was proposed in 1980 as a means of nondestructive internal observation using ultrasonic signal excited by a choppedelectron beam. In a series of EAM studies, we have used semiconductor devices as a specimen. In this study, a ceramic disk making with a hot pressing method was lapped and a part of the disk surface was coated Au by vacuum deposition. The Au film on the surface was grounded for descharge. The disk used as a specimen, EAM images (EAIs) were obtained as the same of the devices case. Pores in the disk were detected nondestructively and the observable depth of the disk was depends on the change of acceleration voltage (HV) of the beam. EAIs at three HV conditions, with HV = 25kV, HV = 30kV and HV = 35kV were displayed on a CRT in blue, green and red respectively and were superimposed using a personal computer. The color at the pore in the superimposition image was changed. This indicated that the pore was a distribution with depth direction.