Sn Metal Preparation Process And Properties Of Bonded Ndfeb Magnets

With the progress of the society and the rapid development of science, inthe high-tech fields, the demand of permanent magnetic material is growing,and the study of bonded NdFeB gets more and more. the current researchhotspot is how to make the method of magnets molding from the experimentaltheory to mass production, but the problem need to resolved is to constantlyimprove the level of technology, science and equipment, and to reduce the costof binding magnets, improve the performance to enhance its competitiveness.Research shows that the organic bingder magnets have its defection, such asexcessive internal stress, be affected easily by water, be fragile, pooranticorrosive ability of resistance to organic solvent, cannot be used properly inhigh temperature conditions, limited the range of application of the organicbinder NdFeB magnets. To improve the shortcoming of the organic binder, thehigh-performance bonded NdFeB magnets were prepared by using the metal Snas binder. Meanwhile, the influence of various process variables (passivation,the type and qulity of binder and solvent, rosin, pressure of warm compaction,curing time)on the magnetic properity of bonded NdFeB magnets had beeninvestigated systematically.The results of experiment show that the preparation technology of bondedNdFeB magnets as follows: magnetic powder passivated, additives1%rosin,anhydrous alcohol (0.2ml/g) and10%binder Sn were mixed evenly, when thetemperature was230℃, pressure of warm compaction was1400MPa, theholding time kept10minutes, cooling, magnetization, detection. The optimallymagnetic properties were given in following: denstiy ρ=6.492g/cm~3,remanence Br=0.789T, intrinsic Hcj=719kA/m, maximum energy product(BH)_m=110.9kJ/m~3, compressive strength σbc=81.5Mpa.It is concluded that passivation, additives rosin, solvents, binder Sn, pressureof warm compaction, the curing time have the effect in the certain degree onmagnetic properties of the bonded NdFeB magnets, and are the important effectfactor of the preparation technology of the bonded NdFeB magnets.