Multi-probe impedance measurement system for non-destructive 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 which contacts the surface of the P/M part. The array of measured data is processed to not only detect the presence of flaws, but also determine their location, size, and orientation. Experimental results show detection of flaws ranging in size from 10 μm to 200 μm