Abstract
We have developed a method of powder immersion. Test pieces; components or materials are tested in pressurized powder. The acoustic impedance can be controlled by the pressure applied. This method's strong point is that we are able to match the acoustic impedances of the powder and the test pieces by controlling the pressure of the powder. When the acoustic impedances of the powder and the test pieces match, the reflection of elastic waves is greatly reduced. In this paper we applied the powder immersion method to the testing of engineering plastics and magnesium alloy. We confirmed that the echoes from the test piece surfaces almost completely disappear when the acoustic impedance of the powder matches that of the test piece.
