A method of manufacturing a silicon-containing oxide-coated aluminum nitride particle; a method of manufacturing a heat dispersing resin composition containing the silicon-containing oxide-coated aluminum nitride particle; and the silicon-containing oxide-coated aluminum nitride particle. The method of manufacturing includes: a first step of covering the surface of the aluminum nitride particle with an organic silicone compound including a specific structure; and a second step of heating the aluminum nitride particle covered with the organic silicone compound at a temperature of 300° C. or more and less than 1000° C., wherein the content of carbon atoms in the silicon-containing oxide-coated aluminum nitride particle is less than 1000 ppm by mass.

A method of manufacturing a silicon-containing oxide-coated aluminum nitride particle; a method of manufacturing a heat dispersing resin composition containing the silicon-containing oxide-coated aluminum nitride particle; and the silicon-containing oxide-coated aluminum nitride particle. The method of manufacturing includes: a first step of covering the surface of the aluminum nitride particle with an organic silicone compound including a specific structure; and a second step of heating the aluminum nitride particle covered with the organic silicone compound at a temperature of 300° C. or more and less than 1000° C., wherein the content of carbon atoms in the silicon-containing oxide-coated aluminum nitride particle is less than 1000 ppm by mass.

Provided is a surface-treated spinel particle (B) including a spinel particle (A) including a magnesium atom, an aluminum atom, and an oxygen atom and a surface treatment layer disposed at least a portion of the surface of the spinel particle (A). The surface treatment layer includes a surface-treating agent including an organic compound or a cured product of the surface-treating agent. The spinel particle (A) further includes molybdenum. The crystallite diameter of the [111] plane of the spinel particle (A) is 220 nm or more. Also provided are a method for producing the surface-treated spinel particle (B), a resin composition including the surface-treated spinel particle (B), and a molded article.

Provided is a surface-treated spinel particle (B) including a spinel particle (A) including a magnesium atom, an aluminum atom, and an oxygen atom and a surface treatment layer disposed at least a portion of the surface of the spinel particle (A). The surface treatment layer includes a surface-treating agent including an organic compound or a cured product of the surface-treating agent. The spinel particle (A) further includes molybdenum. The crystallite diameter of the [111] plane of the spinel particle (A) is 220 nm or more. Also provided are a method for producing the surface-treated spinel particle (B), a resin composition including the surface-treated spinel particle (B), and a molded article.

To provide plate-like alumina particles that are less likely to wear apparatuses. Plate-like alumina particles containing germanium or a germanium compound. The plate-like alumina particles preferably have a molar ratio of Ge to Al, [Ge]/[Al], of 0.08 or more as determined in an XPS analysis. The plate-like alumina particles preferably contain the germanium or germanium compound in a surface layer. The plate-like alumina particles preferably have a density of 3.7 g/cm.sup.3 or more and 4.1 g/cm.sup.3 or less. The plate-like alumina particles preferably have a molar ratio of Ge to Al, [Ge]/[Al], of 0.08 or less as determined in an XRF analysis.

A method of producing new hydrophobic aluminas by i) providing a slurry comprising an alumina compound, the slurry having a pH of above 5.5; ii) mixing an organic composition comprising carboxylic acids with long hydrocarbon chains with the slurry to form an acid modified slurry; iii) hydrothermally conditioning the acid modified slurry to form a hydrothermally aged slurry; and iv) drying the hydrothermally aged slurry. The new hydrophobic aluminas have surface modified structures distinguished by a low humidity content and very small nanoparticles. These new hydrophobic aluminas can be uniformly dispersed in a substrate, for example polymers.

The present invention provides a new glitter pigment suitable for providing high-brightness whitish reflected light. The glitter pigment according to the present invention includes: a flaky substrate 1; and a silicon oxide layer 2 and a titanium oxide layer 3 formed in this order on the flaky substrate 1, wherein in the case where the flaky substrate is the glass flake, the glass flake has a thickness of 284 to 322 nm, the silicon oxide layer has a thickness of 89 to 109 nm, and the titanium oxide layer has a thickness of 51 to 86 nm. In the case where the flaky substrate is the alumina flake, the alumina flake has a thickness of 260 to 280 nm, the silicon oxide layer has a thickness of 79 to 102 nm, and the titanium oxide layer has a thickness of 47 to 87 nm.

The present invention provides a new glitter pigment suitable for providing high-brightness whitish reflected light. The glitter pigment according to the present invention includes: a flaky substrate 1; and a silicon oxide layer 2 and a titanium oxide layer 3 formed in this order on the flaky substrate 1, wherein in the case where the flaky substrate is the glass flake, the glass flake has a thickness of 284 to 322 nm, the silicon oxide layer has a thickness of 89 to 109 nm, and the titanium oxide layer has a thickness of 51 to 86 nm. In the case where the flaky substrate is the alumina flake, the alumina flake has a thickness of 260 to 280 nm, the silicon oxide layer has a thickness of 79 to 102 nm, and the titanium oxide layer has a thickness of 47 to 87 nm.

To provide an aluminum nitride particle having a hexagonal columnar barrel part and bowl-like projection parts at both ends of the columnar part, wherein the long diameter (D) of the barrel part is 10 to 250 μm, the ratio (L.sub.1/D) of the distance (L.sub.1) between the apexes of the two projection pars to the long diameter (D) of the barrel part is 0.7 to 1.3, and the percentage of the length or thickness (L.sub.2) of the barrel part to the distance (L.sub.1) between the apexes of the two projection parts is 10 to 60%. The aluminum nitride particle can provide high heat conductivity and excellent electric insulation to a resin when it is filled into the resin.

To provide an aluminum nitride particle having a hexagonal columnar barrel part and bowl-like projection parts at both ends of the columnar part, wherein the long diameter (D) of the barrel part is 10 to 250 μm, the ratio (L.sub.1/D) of the distance (L.sub.1) between the apexes of the two projection pars to the long diameter (D) of the barrel part is 0.7 to 1.3, and the percentage of the length or thickness (L.sub.2) of the barrel part to the distance (L.sub.1) between the apexes of the two projection parts is 10 to 60%. The aluminum nitride particle can provide high heat conductivity and excellent electric insulation to a resin when it is filled into the resin.