Blog | LGC ARMI

Positive Material Identification

Written by Dave Coler | Jan 23, 2018 9:00:00 AM

Positive material identification or PMI is the  verification of metal alloys based on their chemical composition.  This methodology is used for a wide range of applications where the grade of metal alloy used in a particular application needs to be confirmed.  PMI is used in a wide range of applications, but most commonly in industrial settings where using the wrong metal alloy grade  can result in premature corrosion or even failure creating a potentially serious safety hazard.  The chemical verification of alloys already being used in industrial applications often requires that the analysis be non -destructive and performed insitu.  This is most commonly performed using a handheld XRF unit often called a "PMI gun" or portable OES instrument.  

These units are usually pre-calibrated  with a general purpose application in the factory and are programmed to readout the alloy grade based on the chemical analysis collected by the instrument.  These portable systems are relatively easy to use and and the analysis is fast enough that a large number of quality checks can be completed by a single person in one shift. 

While the instruments are pre-calibrated, it is often recommended that a certified reference material of the metal alloy being verified be used as a check sample.  ARMI provides a wide range of metal alloy CRM's covering  stainless, carbon and low alloy steels, copper, brass and bronzes, nickel and cobalt alloys, titanium alloys and aluminum alloys.  These are available as thin discs appropriate for use with  handheld XRF or portable OES units.

See what is available on our product page or contact us for more details.  If you need a CRM of an alloy grade we don't have, let us know and we can develop one.