MAGNETIC PARTICLE INSPECTION Can find both surface and near sub-surface defects,Some inspection formats are extremely portable and low cost

Magnetic particle inspection (often abbreviated MT or MPI) is a nondestructive inspection method that provides detection of linear flaws located at or near the surface of ferromagnetic materials.

Since the wavelength of the crystal emission is between 350 and 750 nm, the wavelength is not very long, and the crosstalk caused is small. In addition, the distance between the diode pixels is relatively large, 0.5 mm, which greatly reduces the cross

Nondestructive testing (NDT) provides the ability to monitor various aspects of material and product quality without compromising part integrity.

The response peak of the diode is 800---900 nm, and the relative response at 560 nm is only about 50%.

There are an assortment of NDT techniques used throughout a broad cross-section of industries. The five most widely used techniques being radiography, ultrasonics, eddy current, liquid penetrant and magnetic particle.