Slurry parameters were controlled prior to spray-drying to visualize and govern an understanding of which parameters govern hollow coring and granule morphology during spray-drying. An aqueous alumina using a polyviny...Slurry parameters were controlled prior to spray-drying to visualize and govern an understanding of which parameters govern hollow coring and granule morphology during spray-drying. An aqueous alumina using a polyvinyl alcohol binder (PVA) system was analyzed and granules were processed by altering the slurry specific gravity and viscosity value prior to spray-drying. Spray-dried granules were uniaxial dry-pressed at varying moisture contents to show the plasticizing effects of moisture during compaction. A novel characterization method using a field emission electron microscope (FESEM) was implemented to image the green microstructures of the granules and compacted samples. Slurries with a higher specific gravity and viscosity resulted in denser granules with spherical shapes. Viscosity affected the binder segregation during the spray-drying process. Granules stored at higher moisture contents resulted in denser compacts with fewer intergranular pores and cracks along granule boundaries. Using a FESEM resulted in higher resolution for green microstructural characterization.展开更多
In this work,the BMS-12 pre-sintered material was used as the basic material,and the optimal secondary additive addition amount was found by the wet pressing process.Then,the anisotropic ferrite material was prepared ...In this work,the BMS-12 pre-sintered material was used as the basic material,and the optimal secondary additive addition amount was found by the wet pressing process.Then,the anisotropic ferrite material was prepared by dry-pres sing method,and the effects of camphor adhesives,calcium stearate lubricant and powder particle size on the magnetic properties were studied.The experimental results show that the appropriate addition amount of camphor adhesive and calcium stearate lubricant is 0.6 wt%and 0.8 wt%,respectively.High remanence and coercivity can be obtained for particle size of 0.85-1.00μm.Superior dry-pressed magnet ferrite was prepared with typical properties of magnetic induction intensity of Br=421 mT,induction coercivity of Hcb=296 kA·m-1,intrinsic coercivity of Hcj=369 kA·m-1 and maximum energy product of(BH)max=33.3 kJ·m-3,which have reached the level of TDK corporation product of FB5 D.This shows that the dry-pressed magnet of La-Ca-Sr-Co system has higher remanence and intrinsic coercivity than the traditional wetpressed Sr-ferrite.展开更多
文摘Slurry parameters were controlled prior to spray-drying to visualize and govern an understanding of which parameters govern hollow coring and granule morphology during spray-drying. An aqueous alumina using a polyvinyl alcohol binder (PVA) system was analyzed and granules were processed by altering the slurry specific gravity and viscosity value prior to spray-drying. Spray-dried granules were uniaxial dry-pressed at varying moisture contents to show the plasticizing effects of moisture during compaction. A novel characterization method using a field emission electron microscope (FESEM) was implemented to image the green microstructures of the granules and compacted samples. Slurries with a higher specific gravity and viscosity resulted in denser granules with spherical shapes. Viscosity affected the binder segregation during the spray-drying process. Granules stored at higher moisture contents resulted in denser compacts with fewer intergranular pores and cracks along granule boundaries. Using a FESEM resulted in higher resolution for green microstructural characterization.
基金financially supported by the National Natural Science Foundation of China(No.51401023)the National Basic Research Program of China(No.2014CB643702)Youth Innovation Fund Project of BGRIMM Technology Group(Nos.QCJ201809,QC-201724 and QCJ201820).
文摘In this work,the BMS-12 pre-sintered material was used as the basic material,and the optimal secondary additive addition amount was found by the wet pressing process.Then,the anisotropic ferrite material was prepared by dry-pres sing method,and the effects of camphor adhesives,calcium stearate lubricant and powder particle size on the magnetic properties were studied.The experimental results show that the appropriate addition amount of camphor adhesive and calcium stearate lubricant is 0.6 wt%and 0.8 wt%,respectively.High remanence and coercivity can be obtained for particle size of 0.85-1.00μm.Superior dry-pressed magnet ferrite was prepared with typical properties of magnetic induction intensity of Br=421 mT,induction coercivity of Hcb=296 kA·m-1,intrinsic coercivity of Hcj=369 kA·m-1 and maximum energy product of(BH)max=33.3 kJ·m-3,which have reached the level of TDK corporation product of FB5 D.This shows that the dry-pressed magnet of La-Ca-Sr-Co system has higher remanence and intrinsic coercivity than the traditional wetpressed Sr-ferrite.
