| Due to its’ excellent performance sintered Nd2Fe14B(S-Nd2Fe14B)permanent magnet material being widely used in various fields of national economy and defense industry.With the rapid development of information technology,automation,growing awareness of energy conservation and environmental protection,the demand for Nd2Fe14 B material constantly amplified,The Nd2Fe14 B material be prepared only by Nd,Fe,B elements with a high remanence and energy product,but low coercivity(lower than the theoretical value of 1/3~1/5).It is difficult to satisfy the usage.Even though the way of depening on adding heavy rare earth magnets to improve the coercivity,the over-reliance on scarce resources also increased the production cost.Thus,Preparation of high performance S-Nd2Fe14 B magnet increasingly becomes a hot research.In order to improve coercivity and the value of industrial application,the effects of adding(Neodymium)Nd,Al2O3,nano Titanium(Ti)and(0.2Nd+Ti)wt% on the grain boundary in(Dy/Tb)-free(Pr Nd)31(Al Co Cu Ga Zr)1.55B0.98 Febal ally powders were investigated.The main results were as follows:By grain-boundary with Nd powder,the coercivity of the magnet is significantly improved.The Nd addition on coercivity andremanence respectively accord the line of Hc J=16.19+0.58 x,Br=13.71-0.131 x.By grain boundary adding Al2O3 within the range of 0.0~0.4%(wt.),the magnet coercivity can radiate downward trend after the first rise.Br and(BH)max with Al2O3 added slowly declining.When adding 0.2wt% Al2O3 magnet coercivity significantly increased about 5.0%,the composite magnetic can best.Microstructure observation showed that the grain boundary adding Al2O3 can promote the densification of the magnet,the refractory oxide can pinning grain boundaries,grain refinement,the grain size uniform,which is the cause of increasing the coercivity.Adding nano Ti significantly increased the magnet of Hcj and HK/Hcj.Nano Ti refractory solid form in the presence of grain boundaries during sintering,can inhibit grain growth,pinning the grain boundaries,increasing the coercivity.When the addition amount of 0.0~0.3wt%,the coercivity is increased from 16.15 KOe to 17.56 KOe,Hk/Hcj from 0.83 up to 0.98.When adding 0.1wt% nano Ti,magnetic properties were prepared for the performance of high performance magnet N48 H grades.When the addition amount 0.2wt%,Br felled 0.5%,while the coercivity can be increased by 6.1%,taking into account the cost of added Nano Ti,0.2wt% is the optimal dosage.Grain boundary combined addition of nano Ti and Nd magnet can significantly improve coercivity,the coercivity can be prepared up to 19.28 KOe sintered Nd2Fe14 B magnet without Dy and Tb.Magnet remanence and coercivity amount of change in the composite satisfy the regular that Br=13.65-0.161 x,Hcj=17.32+0.551 x.When Nano Ti compound added 0.2wt% and 1.0wt% Nd,the magnet exceed the standard of N45 H magnetic parameters;adding 0.2wt% Ti composite with the 2.0wt% Nd,the magnetic properties can be prepared to adapt to wind turbines magnet.That can be provided a good reference value to preparation of(Dy/Tb)-free sintered Nd Fe B to improve the coercivity. |
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