Nanoporous ceramic for atomization core and preparation method thereof
The present disclosure discloses a nanoporous ceramic for an atomization core, and a preparation method thereof. The nanoporous ceramic includes: nano-silica 1 to 60 parts, a ceramic powder 10 to 80 parts, a pore-forming agent 1 to 50 parts, and a sintering additive 1 to 40 parts. The preparation method includes: (1) weighing raw materials, and mixing and ball-milling the raw materials in a ball mill; (2) bake-drying the ball-milled raw materials to obtain a dried mixed powder; (3) adding the dried mixed powder to molten paraffin under stirring, and continuously stirring a resulting mixture to obtain a paraffin slurry; (4) injecting the paraffin slurry into a mold, cooling the mold for forming, and performing demolding to obtain a paraffin mold; (5) preheating the paraffin mold for paraffin removal to obtain a paraffin-removed sample; and (6) sintering and cooling the paraffin-removed sample to obtain the nanoporous ceramic.
1 . A preparation method of a nanoporous ceramic for an atomization core, comprising the following steps:
(1) weighing raw materials including 5 to 40 parts of nano-silica, 20 to 70 parts of a ceramic powder, 5 to 30 parts of a pore-forming agent, and 1 to 20 parts of a sintering additive, and mixing and ball-milling the raw materials in a ball mill, wherein the nano-silica comprises colloidal nano-silica or powdery nano-silica, nanoparticles of the nano-silica have a primary particle size of 10 nm to 150 nm, and an amount of the colloidal nano-silica is calculated based on solid silica in the colloidal nano-silica; the ceramic powder comprises at least one selected from the group consisting of kaolin, diatomaceous earth, aluminum oxide, silicon nitride, silicon carbide, quartz sand, glass sand, clay, and a feldspar powder; and the sintering additive comprises at least one selected from the group consisting of boron oxide, boric acid, oleic acid, stearic acid, sodium silicate, calcium oxide, iron oxide, and titanium oxide;
(2) oven-drying the ball-milled raw materials obtained in step (1) to obtain a dried mixed powder;
(3) heating paraffin to molten paraffin, adding the dried mixed powder to the molten paraffin under stirring, and continuously stirring a resulting mixture for 1 hour to 8 hours to obtain a paraffin slurry;
(4) injecting the paraffin slurry into a mold prepared in advance, cooling the mold for forming, and performing demolding to obtain a paraffin mold;
(5) preheating the paraffin mold for paraffin removal to obtain a paraffin-removed sample; and
(6) sintering the paraffin-removed sample to obtain the nanoporous ceramic, wherein the sintering comprises heating, temperature-holding, and cooling.
2 . The preparation method of a nanoporous ceramic for an atomization core according to claim 1 , wherein in step (1), the ball mill has a rotational speed of 150 rpm to 500 rpm, the ball-milling is conducted for 1 hour to 10 hours, and a milling material has a diameter of 1 mm to 50 mm.
3 . The preparation method of a nanoporous ceramic for an atomization core according to claim 1 , wherein in step (2), the oven-drying is conducted at a temperature of 60° C. to 150° C. for at least 1 hour, the paraffin has a melting point of 50° C. to 120° C., and the paraffin is added at an amount 10% to 60% by weight based on a weight of the dried mixed powder.
4 . The preparation method of a nanoporous ceramic for an atomization core according to claim 1 , wherein in step (5), the paraffin removal is conducted at a temperature of 400° C. to 800° C. for 2 hours to 12 hours.
5 . The preparation method of a nanoporous ceramic for an atomization core according to claim 1 , wherein in step (6), the sintering is conducted at a temperature of 600° C. to 1,500° C. with a heating rate of 1° C./min to 10° C./min and a holding time of 2 hours to 12 hours.
6 . The preparation method of a nanoporous ceramic for an atomization core according to claim 1 , wherein in step (6), the sintering is conducted in a protective atmosphere, and the protective atmosphere is one or more selected from the group consisting of a reductive hydrogen atmosphere and an inert atmosphere.
7 . The preparation method of a nanoporous ceramic for an atomization core according to claim 1 , wherein the pore-forming agent comprises at least one selected from the group consisting of graphite, a starch, wheat flour, bean flour, a polystyrene microsphere, a polymethyl methacrylate microsphere, a carbonate, an ammonium salt, sucrose, and a fiber, and the pore-forming agent has a particle size of 1 μm to 200 μm.
8 . The preparation method of a nanoporous ceramic for an atomization core according to claim 7 , wherein the pore-forming agent is flake graphite with a particle size of 1 μm to 20 μm.