Embodiments disclosed herein relate to using cobalt (Co) to fine tune the magnetic properties, such as permeability and magnetic loss, of nickel-zinc ferrites to improve the material performance in electronic applications. The method comprises replacing nickel (Ni) with sufficient Co.sup.+2 such that the relaxation peak associated with the Co.sup.+2 substitution and the relaxation peak associated with the nickel to zinc (Ni/Zn) ratio are into near coincidence. When the relaxation peaks overlap, the material permeability can be substantially maximized and magnetic loss substantially minimized. The resulting materials are useful and provide superior performance particularly for devices operating at the 13.56 MHz ISM band.

In additive manufacturing operations, powders used in stereolithographic processes need to be precisely spread out in a uniform fashion at every pass of the stereolithographic process to ensure predictability in powder surface morphology. Typically, this is difficult to achieve with conventional powders because often these powders suffer from poor flowability, which may further deteriorate over time, and impairs the efficiency of the stereolithographic processes. The present disclosure describes additive manufacturing powders having improved physical characteristics such as flowability and tap density, which are less sensitive or insensitive to ambient humidity. For example, there is described a powder that includes spherical particles having a particle size distribution of less than 1000 micrometers and having a measurable flowability as determined in accordance with ASTM B213 at 75% relative humidity.

A magnetic material which is likely to be cracked or chipped. The magnetic material is a magnetic material including ferrite particles and segregated particles containing Bi and Si, and characteristically, the magnetic material contains, as a main constituent, 46.0 mol % to 50.0 mol % Fe.sub.2O.sub.3, 0.4 mol % to 8.0 mol % CuO, 23.0 mol % to 32.0 mol % ZnO, and 18.0 mol % to 22.0 mol % NiO, and the ratio of the average particle size of the segregated particles to the average particle size of the ferrite particles is 0.04 or more and 0.19 or less (i.e., 0.04 to 0.19).

A coil device comprising a coil, and a ferrite core arranged in a hollow portion of the coil, and a resin covering them; the ferrite core being a Ni ferrite core having initial permeability μi of 450 or more at a frequency of 100 kHz and a temperature of 20° C., and an average crystal grain size of 5-9 μm, both of temperature-dependent inductance change ratios TLa and TLb and stress-dependent inductance change ratios PLa and PLb being −0.6% to +0.6%, and both of the sum of TLa and PLa and the sum of TLb and PLb being more than −1.0% and less than +1.0%; and an antenna comprising it.

A ferrite composition includes main-phase particles, first sub-phase particles, second sub-phase particles, and a grain boundary. At least 10% or more of the main-phase particles contain a portion whose Zn concentrations monotonously decrease from a particle surface toward a particle central part along a length of 50 nm or more. The first sub-phase particles contain Zn.sub.2SiO.sub.4. The second sub-phase particles contain SiO.sub.2. A total area ratio of the first sub-phase particles and the second sub-phase particles is 30.5% or more.

The present invention provides: a ferrite particle containing a crystal phase component containing a perovskite crystal represented by the compositional formula RZrO.sub.3 (where R is an alkaline earth metal element); and an electrophotographic developer carrier core material, an electrophotographic developer carrier, and an electrophotographic developer containing the ferrite particles.

A ferrite composition includes a main component and a sub-component. The main component includes 10.0 to 38.0 mol % of a Fe compound in terms of Fe.sub.2O.sub.3, 3.0 to 11.0 mol % of a Cu compound in terms of CuO, 39.0 to 80.0 mol % (excluding 39.0 mol %) of a Zn compound in terms of ZnO, and a balance of a Ni compound. The sub-component includes 10.0 to 23.0 parts by weight of a Si compound in terms of SiO.sub.2, 0 to 3.0 parts by weight (including 0 parts by weight) of a Co compound in terms of Co.sub.3O.sub.4, and 0.1 to 3.0 parts by weight of a Bi compound in terms of Bi.sub.2O.sub.3 with respect to 100 parts by weight of the main component.

A ferrite sintered body contains from 48.2% by mole to 49.7% by mole Fe in terms of Fe.sub.2O.sub.3, from 2.0% by mole to 8.0% by mole Cu in terms of CuO, from 12.0% by mole to 19.0% by mole Ni in terms of NiO, and from 28.5% by mole to 33.0% by mole Zn in terms of ZnO, in which when Fe, Cu, Ni, and Zn are converted to Fe.sub.2O.sub.3, CuO, NiO, and ZnO, respectively, and when the total amount of the Fe.sub.2O.sub.3, the CuO, the NiO, and the ZnO is 100 parts by weight, the ferrite sintered body contains from 5 ppm to 25 ppm B in terms of elemental B and 6 ppm to 25 ppm Nb in terms of elemental Nb.

A ferrite sintered body contains Fe, Mn, Zn, Cu, and Ni. Supposing that Fe, Mn, Zn, Cu, and Ni are converted into Fe.sub.2O.sub.3, Mn.sub.2O.sub.3, ZnO, CuO, and NiO, respectively, and the sum of the contents of Fe.sub.2O.sub.3, Mn.sub.2O.sub.3, ZnO, CuO, and NiO is 100 mol %, the sum of the contents of Fe.sub.2O.sub.3 and Mn.sub.2O.sub.3 is 48.47 mol % to 49.93 mol %, the content of Mn.sub.2O.sub.3 is 0.07 mol % to 0.37 mol %, the content of ZnO is 28.95 mol % to 33.50 mol %, and the content of CuO is 2.98 mol % to 6.05 mol %. Furthermore, 102 ppm to 4,010 ppm Zr in terms of ZrO.sub.2 and 10 ppm to 220 ppm Al in terms of Al.sub.2O.sub.3 are contained per 100 parts by weight of the sum of the amounts of contained Fe.sub.2O.sub.3, Mn.sub.2O.sub.3, ZnO, CuO, and NiO.

A ferrite sintered body contains from 45.0% by mole to 49.7% by mole Fe in terms of from Fe.sub.2O.sub.3, 2.0% by mole to 8.0% by mole Cu in terms of CuO, from 25.0% by mole to 45.0% by mole Ni in terms of NiO, and from 1.0% by mole to 20.0% by mole Zn in terms of ZnO, in which when Fe, Cu, Ni, and Zn are converted to Fe.sub.2O.sub.3, CuO, NiO, and ZnO, respectively, and when the total amount of the Fe.sub.2O.sub.3, the CuO, the NiO, and the ZnO is 100 parts by weight, the ferrite sintered body contains from 5 ppm to 25 ppm B in terms of elemental B and from 6 ppm to 25 ppm Nb in terms of elemental Nb.