Magnetic particle Inspection (MPI) is a non-destructive testing (NDT) process for detecting surface and near surface flaws in ferromagnetic materials and is Primarily used for crack detection. Introducing a magnetic field into the materials either locally or overall. The material can be magnetized by direct or indirect magnetization. If there is a surface-breaking flaw, the magnetic field is distorted, causing local magnetic flux leakage around the flaw. This leakage flux is displayed by covering the surface with very fine iron particles applied either dry or suspended in a liquid. The particles accumulate at the regions of flux leakage, producing a build-up which can be seen visually even when the crack opening is very narrow. Thus, a crack is indicated as a line of iron powder particles on the surface.