What Is Positive Material Identification?
What Is Positive Material Identification?
Positive Material Identification is a non destructive testing method used for verifying the chemical composition of various materials, primarily metals and alloys. Positive Material Identification testing is a relatively fast form of non destructive testing, that is primarily used to verify that supplied materials conform to the right specifications and standards for the purpose that they need to be used for. The most common form of positive material identification testing is X-Ray fluorescence, using a handheld gun that is portable, easy to use and cost effective, allowing it to be used on or offsite in the field, production floor or a non destructive testing laboratory. Positive Material Identification is used for safety compliance and quality assurance to make sure that the correct materials are being used for the purpose that is intended. Its use is incredibly important in such fields such as power generation, oil & gas, manufacturing, pharmaceutical, nuclear, aerospace and metal fabrication.
How Does X-Ray Fluorescence Work?
X-Ray Fluorescence, often abbreviated to XRF, is the most widely used form of positive material identification. XRF is a process where electrons are displaced from their atomic orbital positions, which releases a burst of energy that corresponds with a particular element. The X Ray Fluorescence gun works by firing an X-Ray beam with enough energy to displace the electrons from the inner shells from an X-Ray tube within the gun itself. This displacement occurs as a result of the difference in energy between the primary X-ray beam emitted from the gun and the binding energy that holds electrons in their proper orbits; the displacement happens when the X-ray beam energy is higher than the binding energy of the electrons with which it interacts. When electrons are knocked out of orbit, the atom becomes unstable, and must immediately correct this by replacing the lost electron with another from higher up in the orbit. This is known as fluorescence. Because electrons have higher binding energies the further they are from the nucleus of an atom, the atoms will lose energy when this takes place, equivalent to the distance between each electron shell, which is different for each element. The XRF gun then registers this energy, and categorizes the material being inspected by the presence of these energies and allows the user to get a good idea of how much of each material is present in the material being tested.
The entire X Ray Fluorescence process takes only a small fraction of a second, which allows non destructive testing technicians to receive positive material identification results very quickly within seconds. For large samples with lots of different elements in small parts per million quantities this may take slightly longer, but no longer than a few minutes. Positive material identification using X-Ray fluorescence is known for its speed and accuracy with results. For more information on the applications of positive material identification and how SureCheck can help you with other NDT Solutions, contact us today!
To learn more about why NDT is essential, read our guide to “Why Is Non Destructive Testing So Important”.
Alongside Positive Material Identification, there are many other techniques that can be used either in conjustion with PMI testing or as an alternative. You can read more about these below:
How does Magnetic Particle Inspection Work?
