Flaky alumina particles including mullite in a surface layer of the flaky alumina particles. A method for producing flaky alumina particles including forming a mixture by mixing together an aluminum compound that contains elemental aluminum, a molybdenum compound that contains elemental molybdenum, and silicon or a silicon compound that contains elemental silicon, the aluminum compound being in an amount greater than or equal to 50 mass %, calculated as Al.sub.2O.sub.3, the molybdenum compound being in an amount less than or equal to 40 mass %, calculated as MoO.sub.3, the silicon or the silicon compound being in an amount of 0.5 mass % or greater and less than 10 mass %, calculated as SiO.sub.2, relative to a total mass of the flaky alumina particles taken as 100 mass %; and firing the mixture.

Provided is a color encoding method including providing a composition including a liquid medium and magnetic nanoparticles dispersed in the liquid medium; applying a magnetic field to the composition to align the magnetic nanoparticles; and applying a patterned energy source to the composition to solidify the composition, wherein more than one region of the composition are sequentially solidified with varying magnetic field strength to fix a plurality of color codes.

The present invention relates to a method for producing a magnetic powder, including: preparing a precursor solution containing an iron precursor and a silica precursor; spraying the precursor solution to form iron/silica precursor droplets; drying the iron/silica precursor droplets to produce iron/silica precursor particles; and heat treating the iron/silica precursor particles to produce an iron oxide/silica composite powder in which iron oxide particles are embedded in a silica matrix. The present invention also relates to a magnetic powder produced by the method. The present invention may provide an iron oxide magnetic powder that does not use rare earth elements and a method for producing the same.

With an aim to provide an oxide particle with controlled color characteristics, the present invention provides a method for producing an oxide particle, wherein the color characteristics of the oxide particle are controlled by controlling a M-OH bond/M-O bond ratio, which is a ratio of a M-OH bond between an element (M) and a hydroxide group (OH) to a ratio of an M-O bond between the element (M) and oxygen (O), where the element (M) is one or plural different elements other than oxygen or hydrogen included in the oxide particle selected from metal oxide particles and semi-metal oxide particles. According to the present invention, by controlling the M-OH bond/M-O bond ratio of the metal oxide particle or the semi-metal oxide particle, the oxide particle with controlled color characteristics of any of reflectance, transmittance, molar absorption coefficient, hue, and saturation can be provided.

Various embodiments of the present disclosure provide an additive manufacturing method. The method includes forming a first layer of a first ceramic material and forming a second layer of a second ceramic material. The method further includes contacting the first layer of the first ceramic material, the second layer of the second ceramic material, or both with a saturant. The method further includes heating the first layer of the first ceramic material, the second layer of the second ceramic material, or both to a temperature in a range of from about 50° C. to about 300° C. The method further includes applying pressure to the first layer of the first ceramic material, the second layer of the second ceramic material, or both. The pressure can be in a range of from about 10 kPa to about 800 MPa. The method further includes at least partially dissolving a portion of an external surface of a ceramic particle of the first layer of the first ceramic material, the second layer of the second ceramic material, or both. The method further includes fusing a portion of the dissolved portion of the external surface of the ceramic particle to from a product having a density in a range of from about 65% to about 100% relative to a corresponding fully densified product and optionally containing no organic binder.

The present invention relates to silicon-compound-coated fine metal particles, with which surfaces of fine metal particles, composed of at least one type of metal element or metalloid element, are at least partially coated with a silicon compound and a ratio of Si—OH bonds contained in the silicon-compound-coated fine metal particles is controlled to be 0.1% or more and 70% or less. By the present invention, silicon-compound-coated fine metal particles that are controlled in dispersibility and other properties can be provided by controlling the ratio of Si—OH bonds or the ratio of Si—OH bonds/Si—O bonds contained in the silicon-compound-coated fine metal particles. By controlling the ratio of Si—OH bonds or the ratio of Si—OH bonds/Si—O bonds, a composition that is more appropriate for diversifying applications and targeted properties of silicon-compound-coated fine metal particles than was conventionally possible can be designed easily.

Methods and systems are described for fabricating a component using 3D printing. A 3D printed piece is created including a body of the component, a support structure, and a first sacrificial interface region coupling the body of the component to the support structure. The body of the component is formed of a first metal or ceramic material and the first sacrificial interface region is formed at least partially of a second metal or ceramic material. The body of the component is then separated from the support structure by applying a chemical or electrochemical dissolution process to the 3D printed piece. Because the second metal or ceramic material is less resistant to the dissolution process than the first metal or ceramic material, the first sacrificial interface region at least partially dissolves, thereby separating the body of the metal component from the support structure, without dissolving the body of the component.

Methods and apparatuses for in situ synthesis of alloys and/or composites are disclosed, the method comprising: (a) providing an apparatus having: an electromagnetic energy source; an autofocusing scanner; a powder system; a powder delivery system; and computers coupled and configured to control the electromagnetic energy source, the autofocusing scanner, the powder system, and the powder delivery system; (b) programming the computers with structural and material specifications of the sample; (c) using the computers to control electromagnetic radiation, powder mixture, and powder deposition parameters; and (d) focusing and scanning the electromagnetic radiation onto the sample while two or more powders are concurrently deposited onto the sample to deposit layers onto the sample for multiple metal powder synthesis, metal and ceramic synthesis, ceramic synthesis, and/or gradated composition synthesis, wherein the layers comprise at least one new material which differs from the two or more powders. Other embodiments are described and claimed.

A silicon oxide-coated iron powder has a small particle diameter, can achieve high in a high frequency band, and has high insulating property. In a method for producing the powder, a silicon alkoxide is added to a slurry containing iron powder having an average particle diameter of 0.25 m or more and 0.80 m or less and an average axial ratio of 1.5 or less dispersed in a mixed solvent of water and an organic material containing water in an amount of 1% by mass or more and 40% by mass or less. Then, a hydrolysis catalyst for the silicon alkoxide is added to perform silicon oxide coating, the method resulting in a silicon oxide-coated iron powder having the high in a high frequency band and the high insulating property.

A silicon oxide-coated soft magnetic powder has excellent insulating property and provides a high powder compact density. In making the powder, silicon alkoxide is added to a slurry containing soft magnetic powder containing iron in an amount of 20% by mass or more dispersed in a mixed solvent of water and an organic solvent containing water in an amount of 1% by mass or more and 40% by mass or less. A hydrolysis catalyst for the silicon alkoxide is then added to perform silicon oxide coating. The coated magnetic powder has a coverage factor R of 70% or more defined by R=Si100/(Si+M) (wherein Si and M represent molar fractions of Si and elements constituting the soft magnetic powder obtained by an XPS measurement), a powder compact density of 4.0 g/cm.sup.3 or more, and high at high frequency and high insulating property.