Hirst Magnetic Instruments Ltd, is pleased to announce the extension of the range of its award-winning Pulsed Field Magnetometer (PFM) products – the new products are aimed at small sample testing and quality control for grain boundary diffusion (GBD) magnets allowing users to test sample sizes down to 1x1x1mm and with sample test temperatures from ambient to 200 oC.
The previous generation PFM12 and PFM14 which has been superseded by the generation 8, PFM08-10 have been used by many magnet makers to test thin slices for GBD magnets with excellent results, extensions to the range allow customers to more accurately test smaller samples and cubes where GBD has been selectively applied to both improve magnet performance in applications such as EV motors (and wind turbines) and also reduce magnet costs for these applications.
Find out more of about Generation 8 PFMs
The extended PFM08 range of magnet characterisation/magnetometer can accurately measure the magnetic hysteresis curve and extract key values for all magnetic materials (Ferrite, NdFeB, SmCo, AlNiCo and coated magnets). The PFM can apply a field of up to 10.5 Tesla so even the most coercive materials and highest grades of Neodymium (NdFeB) magnets can be accurately measured. Traditional permeameters cannot measure these high coercivity materials due to pole piece saturation limitations.
Hirst PFMs perform a full 4 quadrant measurement of the magnetic hysteresis loop of the material using their integral magnetiser and demagnetiser. This means they can work with magnetised and unmagnetised samples without the need for an external magnetiser.
As well as larger sample sizes, greater levels of temperature control, and improved measurement repeatability the PFM08 generation of machines also includes a new Hirst algorithm called Self Demagnetization Field Function, SDFF™, that accurately generates an open-to-closed circuit mapping (O2C™). The SDFF™ maps the PFM open-circuit measurement onto a closed-circuit, permeameter-like measurement. The SDFF™ is part of a powerful magnetic material characterisation software suite called HirstLab v2.0.
Hirst have worked in collaboration with the National Institute of Metrology (NIM) in China, the University of Exeter, and the UK National Physics Laboratory (NPL) on PFM development over a number of years. The HirstLab v2.0 software and Hirst proprietary SDFF™ technology has been implemented in collaboration with the National Institute of Metrology (NIM), Beijing, as part of a contract for the first PFM08-30 MT placed by NIM.
The first generation of Hirst industrial PFM was launched in 1998 and the company won an Institute of Physics business award for the PFM and SDFF™ technology in 2020.