Preparation Process And Performance Of Bonded Magnet

Recent years, with the development of microelectronic technique, all of the electronic products are becoming smaller and portable in the market. Micro-machine is used widely in the electronic products to meet the needs. Now, ferrite is the main materials of micro-machine in the market, and by sintering to make all kinds of products. But it makes sintered magnets could not meet the needs that deformation in sintering, low yield, low dimensional precision, low shock strength and difficult in multipolar magnetism charging, even worse is that the magnet and the axle can't be made to be a whole in the same step. With low density compared to the sintered magnet, bonded magnet is good for light weight of electric appliance;meanwhile with the bonder it can be made to products with all kinds of shape;with better uniformity and high precision, it is better for mass production;what's more, its shockproof, easy magnetism charging in multipolar and machine-shaping with axle. Just for its so many merits, it is absorbing more and more noticing.This paper focus on the influence of the bonder, anti-friction material, resin acceptor and the powder on the bonded magnet, and draw some conclusions following:1. to study the influence of anti-friction material by adding different anti-friction material and with different adding method;by surface treatment of the powder to study the function of resin acceptor to the magnet, meanwhile analysis the influence of the procession, and made some conclusions:First: found the best way to add the anti-friction materials: at first coating the surface of powder with plastering, then coating it again with solution .of anti-friction uniformly, thus enhance the magnetic properties and its distribution, also we found that 4wt% is the best way to adding the anti-friction materials.Second: annexing agent is very important in surface treatment, phthalate could distribute well with small magnitude, but poor shock resistance;silicohydride consists well with resin for its functional group which has cross linkage with plastering in itshydrophobic group and thus enhance the shock resistance, but with large magnitude;Third: specific surface area of nylonl2 is far large than that of nylon6, so as plastering nylon 12 need more magnetic powder than nylon6, and under a certain powder second-prilling can optimize the distribution, but to control the temperature is key operation or the nylon will become deteriorative.2. by measuring ^ analysis^ comparing different powder and magnetic-motor, we can conclude:First: plate powder is better to enhance the density of injection magnet and its properties, the properties n grain size distribution > pattern x liquidity and the damage of the powder after injection influence the magnetic properties, it can improve the properties with the powder which optimized by two grain size distribution and new mixing process.Sencond: pack density influence the motor magnet greatly, the relation between Hc^ Bs and pare:Hc=Hci (1-p) fnBs=pBsiTo raise He demands lowing P, but to raise the magnetism demands high p, they are contradictory, so how to control the pack density p is very important in the motor making.