5050) of 100-900 nm. The α-alumina particles are produced in such a way that pseudobohemite is mixed with a fluoride-based mineralizer and ultrapure water and pulverized to obtain a powder which is then fired and grown into a polyhedral shape. The polyhedral alumina particles make surface contact and are coated on the surface of a porous polymer substrate, and empty space induced by the interstitial volume between particles is formed larger than that of spherical particles, thereby being capable of achieving excellent air permeability while effectively suppressing thermal contraction of the porous polymer substrate. In addition, due to a nano-level particle size, excellent dispersibility and the formation of a thin coating layer can be achieved.
H01M 50/446 - Composite material consisting of a mixture of organic and inorganic materials
H01M 50/449 - Separators, membranes or diaphragms characterised by the material having a layered structure
H01M 50/489 - Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
C09D 1/00 - Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
C09D 7/00 - Features of coating compositions, not provided for in group ; Processes for incorporating ingredients in coating compositions
2.
PLATE TYPE Α-ALUMINA AND MANUFACTURING METHOD THEREFOR
The present invention provides a method for manufacturing plate type α-alumina particles, plate type α-alumina particles produced therefrom, and a pearlescent pigment comprising same, the method comprising the steps of: (S1) adding pseudoboehmite, molten salt, and additives to a dispersion medium, and mixing, drying, and pulverizing same; (S2) heating dried powder obtained after pulverization in step (S1) to 800-900℃ at a temperature increase rate of 2-3℃/min, and then maintaining same for 4-8 hours to generate seeds; and (S3) heating the seeds produced in step (S2) to 1,000-1,300℃ at a temperature increase rate of 3-5℃/min and then maintaining same for 4 to 6 hours to grow crystals. According to the present invention, it is possible to manufacture plate type α-alumina that can be effectively used as a pearlescent pigment by exhibiting a narrow particle size distribution through the use of pseudoboehmite as a raw material and heat treatment according to stepwise calcination.
The present invention provides an abrasive comprising α-alumina particles having a polyhedral crystal structure, wherein the α-alumina particles have an average diameter (D50) of 300 nm to 10 μm and a bulk density of 0.2-0.5 g/mL, a [0001] face in the crystal structure of the α-alumina particles occupies 10-20% on the basis of the total crystal face area, and the amount of α-alumina particles is 85-100 wt% on the basis of the total weight. The abrasive of the present invention comprises α-alumina particles satisfying predetermined particle size and density ranges while having a polyhedral crystal structure, and thus provides excellent dispersibility in a polishing slurry to enable a polishing rate to increase, while minimizing scratch formation during polishing.
B24B 57/02 - Devices for feeding, applying, grading or recovering grinding, polishing or lapping agents for feeding of fluid, sprayed, pulverised, or liquefied grinding, polishing or lapping agents
B24B 49/00 - Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
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