PMI

Introduction & Principle

Positive Material Identification (PMI) is the testing tool used to identify the materials by detecting the alloy composition. Some of the elements that can be identified using PMI are Ti, V, Cr, Mn, Co, Fe, Cu, Zn, Ni, Se, Nb, Mo.

There are two type of PMI methods used, one is X-ray fluorescence and the other one is Spark emission spectrography.

For X-ray fluorescence type, the equipment contains either radioactive sources or X-ray tube, which sends out radiation. The exposed material then sends temporarily element specific radiation back, generating energy. As every element has its own atomic structure, this reflection will generate a different energy level for every element. This energy is measured and detected and thus identifying the alloy elements. The advantage of the XRF method is used to execute without damaging the material, easy for operation and result available immediately.

Spark emission Spectrography is based on optical emission. The equipment consists of a probe which releases a spark that is used to vaporize the material being analyzed. The atoms and ions in this vapor produce a spectrum which can be optically measured and then recalculated to determine the components of the material.

Application

PMI is applied whenever the customer required the certainty of composition of the material or whenever the material test certificate is not available. PMI is one of the major testing tools used on construction projects.