Theory and Method
A Ferrograph works by passing an oil sample across a ferrographic substrate positioned in a magnetic field. Ferrous particles deposit strongly along the magnetic gradient, while non-ferrous particles and contaminants deposit according to flow and settling behavior. This creates a deposition track in which larger and more strongly magnetized particles appear earlier on the slide, helping speed microscopy-based classification.
After preparation, the ferrogram is examined under an optical microscope to classify particle type, size range, surface texture, and likely wear mechanism. The transparent deposition track helps distinguish metallic, organic, and non-metallic debris more easily and that particles are arranged according to magnetization response and size, which improves analysis speed.
