document: Aeroengine turbine disks often consist of paramagnetic, that means non-ferromagnetic Nickel based alloys. Sometimes, parasitic small ferromagnetic particles can be included in these disks that may decrease the mechanical stability. For this reason, in case of a suspicion disks are to be analysed with respect to ferromagnetic inclusions. These inclusions generate a magnetic density which can be measured by a flux gate magnetometer using the magnetic remanence method [1]. The detection principle of ferromagnetic impurities in non-magnetic metallic materials is based on their remanence. Before such a measurement can be carried out, the aeroengine turbine disks are premagnetised in axial direction. As ferromagnetic materials show the well-known hysteresis behaviour, those materials can be magnetised by a strong magnetic field which drives the magnetic material into saturation. When removing the magnetic field, the remanence is left. This remaining flux density is used to detect them in non-magnetic materials.
doc_bio_tags: B I I O O O B O O O O O O O B I I I O O O O O O O O B I I I O O O O O O O O O O O O O O O O B I O O O O B I O O O O O O B I I O O B I I O O B I I I I O O O O O O O O O O O O B O O O O O B I I O B O O O O O O O O O B I O O O O O O O B I I O O O O O O O O B I I I O O O O O B I I O O O O O O O O
extractive_keyphrases: aeroengine turbine disks decrease the mechanical stability detection principle of ferromagnetic impurities ferromagnetic inclusions flux gate magnetometer hysteresis behaviour magnetic density magnetic remanence method measurement paramagnetic parasitic small ferromagnetic particles premagnetised remaining flux density removing the magnetic field strong magnetic field
abstractive_keyphrases: non-ferromagnetic nickel based alloys