Preparation Of Sm 2 Fe 17 Alloy Precursor By Microwave Ultrasonic Synergistic Coprecipitation Method

Sm₂Fe₁₇Nx rare earth permanent magnet material have the advantages of a high saturation magnetization,Curie temperature,high anisotropy field,and its thermal stability,resistance to oxidation and corrosion resistance are very excellent,very promising to become the next mainstream permanent magnet materials.The preparation method of Sm₂Fe₁₇ Nx at this stage are still have the disadvantages of complex process,operational inconvenience,high cost that make it difficult to achieve large-scale industrial production,so it is very necessary to explore a new method for easy industrial production.Preparation of Sm₂Fe₁₇ Nx by co-precipitation reduction diffusion is a cost-effective way,the first step is prepared Sm-Fe composite oxide by co-precipitation,samarium-iron composite oxide via reduction and diffusion that obtained the Sm₂Fe₁₇ alloy,and then conduct nitride processing to Sm₂Fe₁₇ alloy,finally obtain Sm₂Fe₁₇ Nx rare earth permanent magnet material.Suitable particle and morphology of samarium iron composite oxide is the basis for excellent Sm₂Fe₁₇ Nx,there are many studies about the preparation of samarium-iron composite oxide by co-precipitation,but it is rarely study about the preparation of samarium-iron composite oxide by microwave and ultrasonic synergistic co-precipitation method.Therefore,based on the current research method,preparation of suitable size and uniform morphology of Sm-Fe composite oxide by the collaborative of microwave and ultrasound,the main work and the related results are as followsIn this paper,ferric chloride and samarium chloride as raw materials,ammonium bicarbonate as the precipitating agent,the impact of heating,ultrasonic power,ultrasonic time,pH,dispersant,reaction temperature,aging time on the Sm-Fe composite oxide precursor particle were investigated.Experimental results show that it can obtain the right size Sm-Fe composite oxide precursor on the conditions of the microwave and ultrasonic synergy,microwave heating,ultrasonic power 150 W,ultrasonic duration 15 min,pH value of 6,the reaction temperature is 25 ?,aging time of 1h;The effect of polyethylene glycol to improve the aggregate on Sm-Fe composite oxide precursor is not obvious.Drying process mainly study the effects of microwave drying and conventional electric vacuum drying on the morphology and particle size of the precursor,also studied weight loss during drying process,the results showed that: the precursor that prepared by microwave drying have regular morphology,more full and uniform distribution of particles,much better than the conventional electric vacuum dried precursor,drying process within the first 90 min is more serious weight loss,followed by periods of weight loss situation is not particularly obviously,180 min until no further weight change,so the optimum drying time is 180 min.The thermal decomposition process mainly study the influence of thermal decomposition temperature and time on the morphology and particle size of Sm-Fe composite oxide,TG-DTA analysis shows that thermal decomposition temperature of precursor should be greater than 661 ?;The changes of Sintering temperature will makes the Sm-Fe composite oxide's morphology and size changes greatly,to judge from the morphology and size,optimal sintering temperature is 700 ?;The extended of thermal decomposition holding time will make the Sm-Fe composite oxide particle size increasing,so 60 min is appropriate;The XRD pattern shows that the final product is the composite oxide of Fe₂O₃ and FeSmO₃.