PMI(Material reliability identification)

The full name of PMI is Positive Material identification, то есть, spectral field detection, detection of the content of various elements in the material and brand determination. Mainly used to determine whether the elements in the material meet the requirements of the specification.
There are currently three main methods of PMI testing:
Spectral analysis: various elements can produce their own unique spectra under the excitation of high temperature and high energy, according to the characteristic spectra generated after the element is excited to determine the chemical composition and approximate content of the metal method, called spectral analysis. Обычно, the sample is excited by external energy such as arc, electric spark, laser, и т. д., so that the measured element emits characteristic spectrum. After spectral analysis, it was compared with the spectrum table of chemical elements.
Volumetric analysis: The standard solution (a solution of known concentration) is used to completely react with the measured element in the metal, and then the content of the measured element is calculated according to the volume of the standard solution consumed.
PMI(Material reliability identification)

Spark identification method: mainly used in steel, grinding wheel grinding due to friction, high temperature action, various elements, particles produced when the number of sparks, shape, fork, color and other different, to identify the chemical composition of the material (component elements) and the approximate content of a method.
When conducting material analysis, handheld XRF, ОЭС, and handheld LIBS spectrometers can be used for rapid determination, preparation, and reliable analysis in the field. It is widely used in the production and management of nuclear power plant, нефтехимическая промышленность, машиностроение, casting and forging, waste metal recycling. Helps to identify unknown materials, harmful materials mixed in, thereby improving product quality.
X-ray fluorescence (РФА)
The handheld XRF spectrum analyzer is the most commonly used element identification instrument in the factory, which can provide analysis results quickly and accurately, and is convenient to carry.
PMI(Material reliability identification)

The principle is that the X-ray tube emits a beam of rays into the sample of the workpiece, which excites electrons and separates them from the inner layer, and the vacancy in the inner layer is replaced by the electrons in the outer layer. When the electrons fill the hole, the energy is released in the form of secondary rays, which is fluorescence. Each element will release its own unique energy characteristic spectral line, by measuring the energy characteristic spectral line released by the workpiece sample, you can determine what kind of element exists, through the measurement algorithm of the instrument, you can detect the sample element analysis and element content qualitative and quantitative.
Handheld XRF spectrometers can measure low levels of light elements such as silicon (И), сера (С), phosphorus (п), алюминий (Ал), магний (мг), and more. Однако, elements lighter than magnesium XRF spectrometer, such as carbon (С), и т. д., can not be measured, so this limitation, it is not possible to grade carbon steel and stainless steel, low alloy steel and other materials with low carbon content, and for stainless steel carbon is the basic element of testing different grades of stainless steel, so XRF spectrometer can not distinguish 316 is L, H grade stainless steel.
Laser Induced Breakdown Spectroscopy (LIBS)
PMI(Material reliability identification)

With the development of new technology, the new portable laser element spectrum analyzer has been available, the biggest advantage of the laser spectrometer is that it can measure carbon elements, which can be achieved only in the past, but LIBS does not need external argon cylinder, regulator and other devices, and the argon tank device is inside the instrument, which is very convenient to use. Simply prepare samples on the workpiece sample surface before use, LIBS spectrometers can measure low levels of carbon elements, so it is easy to grade stainless steel, в то же время, it can also calculate carbon equivalent (CE) and residual elements (RE).
The principle is to use a pulsed laser to ablate the surface of the sample and generate plasma. When it cools, the electrons from the cooled plasma are excited, causing the plasma to glow, and each element of the periodic table produces a unique LIBS spectral peak, which can be determined and quantified by a percentage concentration (%) or a parts per million concentration (Ppm) by detecting the characteristic spectral peak and intensity emitted by the element by the detector.