【作者】 黄垒；

【导师】 余红雅；

【作者基本信息】 华南理工大学 ， 材料加工工程， 2018， 硕士

【摘要】 磁粉芯作为一种复合软磁材料,通过粉末冶金工艺压制而成。磁粉芯具有良好的综合性能,它既综合了金属软磁材料和铁氧体软磁材料的优点,同时也可最大限度克服二者的不足。随着科技的快速发展,电子器件向着小型化、大容量、高精度及高灵敏度方向发展,因此要求磁粉芯具有高的饱和磁感应强度、高磁导率、低损耗等优异的性能。FeSiB磁粉芯的饱和磁感应强度较高、损耗较低、直流偏置性能好以及耐腐蚀性好,具有广阔的应用前景。不同粒度的FeSi B磁粉制备的非晶磁粉芯的磁性能不同。FeSiB磁粉粒度较小时,制备的磁粉芯的磁损耗较低,但是磁导率也较低;而磁粉粒度较大时,制备的磁粉芯的磁导率较高,但是磁损耗也较高。针对这一问题,本文针对不同粒度的FeSiB磁粉制备的磁粉芯具有不同的优缺点展开研究。(1)本文针对600目FeSiB磁粉制备的非晶磁粉芯,具有较低的磁损耗,但磁导率也较低,通过添加铁粉制备FeSiB/Fe复合磁粉芯来提高磁导率。主要研究了铁粉含量、磷化处理、磷化液浓度、压制压力及热处理对FeSiB/Fe复合磁粉芯磁性能的影响。通过实验得出结论:铁粉的添加可以有效提高FeSiB非晶磁粉芯的磁导率及饱和磁化强度,但是磁损耗也随着升高。通过对铁粉进行磷化处理,可以保障磁粉芯具有较高磁导率的前提下降低损耗,尤其Fe含量为20wt.%的FeSiB/Fe复合磁粉芯,在50mT、100kHz测试条件下,未被磷化时复合磁粉芯磁损耗为182.1W/kg,而磷化后复合磁粉芯的磁损耗为141.3W/kg,相对降低了22.5%,而且磁导率基本没有变化。基于上述实验,本文对制备工艺进行了优化。实验表明磷化液浓度、压制压力及热处理温度对复合磁粉芯性能影响很大。当铁粉添加量为20wt.%,磷化液浓度为4wt.%,在压制压力为1200MPa,退火温度为450℃时,得到此最佳工艺制备的复合磁粉芯,其磁导率为42.3,磁损耗为141.3W/kg。(2)针对300目FeSiB磁粉制备非晶磁粉芯,具有较高的磁导率,但磁损耗也较高。第一种方案是通过添加铁氧体制备FeSiB/铁氧体复合磁粉芯来降低磁损耗。主要研究了铁氧体粒径、含量对FeSiB/铁氧体复合磁粉芯的性能影响。通过实验得出结论:不同粒径的铁氧体对复合磁粉芯性能影响很大;添加500目铁氧体粉末的复合磁粉芯的磁性能比含有300目和700目铁氧体的复合磁粉芯磁性能较好。在50mT、100kHz测试条件下,铁氧体含量为10wt.%的复合磁粉磁导率为41.0,其磁损耗为115W/kg。相比与FeSiB非晶磁粉芯的磁损耗降低了24.8%,而磁导率有所降低。铁氧体含量对复合磁粉芯的性能影响也很大;含4wt.%铁氧体的复合磁粉芯的磁导率最高为42.4;未添加铁氧体的FeSiB磁粉芯的磁导率为43.3;含4wt.%铁氧体的复合磁粉芯的磁导率基本没有降低。随着铁氧体含量继续增加,复合磁粉芯的磁导率开始下降。随着铁氧体的含量增加,复合磁粉芯的磁损耗随着降低,Q值也会增加。在100kHz条件下,未添加铁氧体的FeSiB磁粉芯的磁损耗为152W/kg,而添加铁氧体质量分数为8wt.%的复合磁粉芯的磁损耗为120W/kg,后者降低了21.7%。第二种方案是通过对FeSiB非晶磁粉进行磷酸盐-有机硅树脂复合包覆来降低磁粉芯的磁损耗。主要研究了磷酸盐-有机硅树脂复合包覆、磷化液浓度及磷化温度对磁粉芯性能的影响。通过实验得出结论:磷酸盐-有机硅树脂复合包覆能够有效降低FeSiB磁粉芯的磁损耗。与未处理的FeSiB磁粉芯相比较,复合包覆的FeSiB磁粉芯的磁损耗降低了30.8%,但是同时也降低了磁粉芯的磁导率。磷化液浓度为6%时,复合包覆的FeSiB磁粉芯的磁损耗最低,相比较于未磷化处理的FeSiB磁粉芯降低了38.5%。磷化温度对磷化效果影响很大。150℃时磷化效果最好,磁粉芯的磁损耗最低,磁导率也较高,所以磷化温度为150℃时,具有较好的综合磁性能。更多还原

【Abstract】 The magnetic powder cores is a kind of composite soft magnetic material,which is prepared by powder metallurgy process.The magnetic powder cores has a good comprehensive performance,and it not only combines the advantages of metal soft magnetic materials and ferrite soft magnetic materials,but also can overcomes the lack of both.With the rapid development of technology,electronic devices are developing toward miniaturization,large capacity,high precision,and high sensitivity.Therefore,magnetic powder cores are required to have excellent properties such as high saturation magnetic induction,high magnetic permeability,and low loss.FeSiB amorphous magnetic powder cores has high saturation magnetic induction,low loss,good DC bias performance and good corrosion resistance,and it has broad application prospects.The magnetic properties of amorphous magnetic powder cores prepared with different particle sizes of FeSiB are different.When the magnetic particle size is small,the magnetic powder cores has low magnetic loss,but the magnetic permeability is also low.When the magnetic particle size is large,the magnetic powder cores has a high magnetic permeability,but the magnetic loss is also high.In order to solve this problem,this paper researches on the advantages and disadvantages of magnetic powder cores prepared with different sizes of FeSiB magnetic powders.The 600-mesh FeSiB amorphous magnetic cores has low magnetic loss and also low magnetic permeability.The purpose of this paper is to improve magnetic permeability by adding iron powder to prepare FeSiB/Fe composite magnetic powder cores.The effect of iron powder content,phosphating treatment,phosphating solution content,pressing pressure and heat treatment on the magnetic properties of FeSiB/Fe composite magnetic cores has been studied.The addition of iron powder can effectively increase the magnetic permeability and saturation magnetization of FeSiB magnetic powder cores,but the core loss also increases.The core loss can be reduced while ensuring high magnetic permeability by phosphating the iron powder,especially when FeSiB/Fe composite magnetic cores with Fe content of 20 wt.%.Under 50 mT,100kHz test condition,the FeSiB magnetic cores has core loss of 182.1W/kg,and the core loss of the composite magnetic cores after phosphating is 141.3W/kg,a relative decrease of 22.5%,and the magnetic permeability does not decrease substantially.Based on the above experiments,the preparation process is optimized.Phosphating solution content,pressing pressure and heat treatment temperature have a great influence on the properties of the composite magnetic cores.When the addition amount of iron powder is 20 wt.%,the concentration of phosphating solution is 4wt.%,the pressing pressure is 1200 MPa and the annealing temperature is 450℃,the composite magnetic cores can be prepared by the optimum process.The magnetic permeability is 42.3,and the core loss is 141.3W/kg.The 300-mesh FeSiB amorphous magnetic cores has high magnetic permeability and also high core loss.In order to reduce the magnetic core loss,the first method is to prepare the FeSiB/Ferrite composite magnetic powder core by adding ferrite powder.The effect of ferrite particle size and content on the performance of FeSiB/ferrite composite magnetic cores has been studied.The addition of ferrite can effectively reduce the magnetic loss of the magnetic powder cores.Ferrite with different particle sizes has a great influence on the properties of composite magnetic powder cores.The composite magnetic powder cores containing 500-mesh ferrite powder has better magnetic properties than the composite magnetic powder cores containing 300-mesh and 700-mesh ferrite powder.Under 50 mT,100kHz test condition,the magnetic permeability of composite magnetic powder containing 10 wt.% ferrite is 41.0,and the core loss is 115W/kg.Compared with FeSiB magnetic powder cores,the core loss is reduced by 24.8%,while the magnetic permeability is reduced.The ferrite content has a great influence on the properties of the composite magnetic powder cores.The magnetic permeability of the FeSi B magnetic powder cores is 43.3,and the magnetic permeability of the composite magnetic cores containing 4wt.% ferrite is up to 42.4 basically no reduction.As the ferrite content continues to increase,the magnetic permeability of the composite magnetic cores decreases.As the content of ferrite increases,the core loss of the composite magnetic cores decreases and the Q value increases.At 100 kHz,the core loss of FeSiB magnetic cores is 152W/kg,while the core loss of composite magnetic cores with 8wt.% ferrite is 120W/kg,a decrease of 21.7%.In order to reduce the magnetic core loss,the second method is to prepare the FeSiB magnetic cores by composite coating of phosphate-silicone resin.The effect of phosphate-silicone resin composite coating,phosphating solution content and phosphating temperature on the properties of the magnetic powder core has been studied.Phosphate-silicone resin composite coating can effectively reduce the core loss of FeSiB magnetic cores.Compared with the untreated FeSiB magnetic powder cores,the magnetic core loss of the composite coating FeSiB magnetic powder cores is reduced by 30.8%,but at the same time,magnetic permeability of magnetic cores are also reduced.When the content of phosphating solution is 6wt.%,the composite coating FeSiB magnetic powder cores has the lowest core loss.Compared with the FeSiB magnetic cores,the composite coating magnetic cores is reduced by 38.5%.Phosphating temperature has great influence on the phosphate effect.150℃ has the best phosphate effect and the lowest er core loss,and the magnetic powder core permeability are higher comparatively.Therefore,when the phosphating temperature is 150℃,it has good comprehensive magnetic properties.更多还原