Positive Material Identification (PMI) is one of the more specialized non-destructive testing methods. With Positive Material Identification the alloy composition of materials can be determined. If a material certificate is missing or it is not clear what the composition of a material is, then PMI offers the solution. PMI is particularly used for high-quality metals like stainless steel and high alloy metals. X-ray Fluorescence (XRF):- XRF analyzers are easy to use, the units are light and small in size, and the sample to be measured does not require much preparation. But, there are limitations on the number of elements that XRF units can measure.