The ambient temperature. Because of sintered ND-Fe-b has a negative temperature coefficient (α-Br<-0.13%/, and α-Hcj<-0.6%/), using the moments highest of environment temperature and maximum temperature will have varying degrees of demagnetization on the magnet itself, both reversible and irreversible, recoverable and unrecoverable.
Environmental humidity. ND-Fe-b itself is prone to corrosion, oxidation, we generally take the form of surface treatment to protect the permanent magnet, but it does not solve the effects of relative humidity on the magnet. Environment the more dry, more long service life of the magnet. How to measure the magnetic properties of the high and low?
There are three main parameters: remanence Br (Residual Induction), Gauss, is a measure of parameters provided by the external magnetic field strength of the magnet and coercive force Hc (Coercive Force) and Oersteds, parameter is a measure of resistance to demagnetization; energy product BHmax, Gauss-Oersteds, energy storage is the characterization of a physical quantity.