Multiprobe impedance measurement system for nondestructive evaluation and test of "green state" powder metallurgy parts

This paper describes an instrument capable of detecting flaws in "green-state" (prior to sintering) powder metallurgy (P/M) parts. The instrument uses a matrix of impedance measurements from a multiprobe array that contacts the surface of the P/M part. The array of measured data is processed to not only detect the presence of flaws but determine their location, size, and orientation as well. Experimental results show detection of flaws ranging in size from 10-200 /spl mu/m.