Abstract:
PURPOSE: A process for producing a spherical boron oxide-based red fluorescent body is provided to save manufacturing costs, to lower the temperature at which the fluorescent body is formed, to prevent the degradation of fluorescent body and to improve productivity. CONSTITUTION: The process for producing a spherical boron oxide based red fluorescent body having the formula: (Y,Gd)BO3:Eu comprises the steps of: (a) adding tetraethyl orthosilicate(TEOS), aqueous ammonia and water to ethyl alcohol and mixing them to precipitate hydrated silica, (b) dispersing the filtered hydrated silica into a precursor solution containing yttrium, gadolinium, europium and boron, controlling the pH to the range of 8-11 with a basic solution to coprecipitate them in the form of hydroxides, and (c) drying the hydroxides and heat treating at the temperature ranged from 800 to 1100 deg.C.
Abstract:
PURPOSE: A method for preparing a barium magnesium aluminate-based blue and green fluorescent substance powder by spray pyrolysis using a nonorganic polymer solution and a barium magnesium aluminate-based blue and green fluorescent substance prepared by the method are provided, to obtain completely spherical fluorescent powder by improving the heat stability. CONSTITUTION: The barium magnesium aluminate-based blue and green fluorescent substance is represented by Ba(a-b)MgcAldOx : Mnb, wherein 0.5
Abstract:
PURPOSE: A preparation method of ceramic powder(3mol%Y2O3-ZrO2) by coprecipitation is provided, which is characterized in that aqueous solution of metal salts and alkali solution are reacted in the ion exchanged water with a specific pH range(pH3-7) unlike conventional coprecipitation method. Accordingly, the prepared ceramic powder has fine and homogeneous particles, less agglomeration, and high sintering density at low temperature. CONSTITUTION: The 3Y-TZP(3mol% Y2O3-Tetragonal Zirconia Polycrystal) powder is prepared by the following steps of: adding aqueous solution of metal salts(0.2-2.0mol) and alkali solution(ammonia water or amine) to ion-exchanged water within a pH range of 3 to 7 for a precipitated slurry; neutralizing the slurry with the alkali solution to be the pH of the slurry between 7-8.5; filtering and thermal treating at 100-200deg.C for 5-20hrs; dispersing filter cakes into ion-exchanged water, filtering, washing and drying; calcining dried powder at 400-1200deg.C for 1-3hrs. The metal salts are selected from ZrOCl28H2O, ZrCl4, ZrO(NO3)2xH2O, YCl3, YCl36H2O, Y(NO3)3xH2O, TiCl4, AlCl3xH2O, CeCl3xH2O, etc.
Abstract:
본 발명은 구상의 알루미네이트계 청색 형광체의 제조방법에 관한 것으로서, 더욱 상세하게는 147nm 또는 172nm의 진공자외선에 의하여 여기되어 가시영역에서 발광 스펙트럼을 나타내는 BaMgAl 10 O 17 : Eu 청색 발광 형광체를 제조하는 방법에 있어서, 적정비율의 물과 알코올의 혼합용액에 알루미늄화합물과 함께 하이드록시프로필 셀룰로오스(이하, HPC) 분산제와 우레아 침전제를 가하여 가수분해시켜 얻은 알루미늄 침전물을 바륨, 마그네슘 및 유로피움 함유 혼합수용액에 분산시키고 옥살산을 가하여 혼합침전물을 얻은 후 공기 및 환원분위기에서 열처리하는 방법으로 형광체를 제조함으로써, 형광체 분말이 종래 고상법의 온도보다 낮은 온도에서 형성되고 특히 입자가 미세한 구상으로 디스플레이 패널 제조시에 고밀도의 형광층을 형성시켜 플라즈 마 디스플레이 패널(이하, PDP)의 성능 향상에 기여할 수 있는 알루미네이트계 청색 발광 형광체의 새로운 제조방법에 관한 것이다.
Abstract:
본 발명은 신규한 녹색 발광 형광체에 관한 것으로서, 더욱 상세하게는 전자선에 의하여 여기되어 가시영역에서 발광 스펙트럼을 나타내는 녹색 발광 형광체를 구성함에 있어 Tb(테르븀)을 활성제로 하고 이 활성제에 대하여 페로브스카이트 구조를 갖는 CaSnO 3 를 새로운 모체조성으로 채용함으로써, 특히 고가의 희토류 원료인 Tb의 사용을 최소화하고 유황(S)성분을 함유하지 않으면서도 종래의 녹색 발광 형광체에 비하여 발광강도가 대단히 우수하여 전자표시관용으로 매우 적합하고 디스플레이 산업 등에 광범위하게 이용될 수 있는 유용한 효과가 있는 신규한 녹색 발광 형광체에 관한 것이다.
Abstract:
The recovery process is characterized by adding an organic solvent to stainless steel waste scraps, which are generated from surface grinding during the rolling process of stainless steel, in a weight ratio of 1 : 2-3 to extract oil and so separately recover oil and stainless steel. The organic solvent is selected from pentane, hexane, heptane, 1,1,1-trichloroethane, trichloroethylene, perchloroethylene, carbon tetrachloride, chloroform and methylene chloride. The oil extraction is repeatedly conducted up to 5 times at the agitation rate of 100-500 rpm. The oil-containing solvent is distilled to recover solvent, and the oil-free stainless steel scrap is centrifuged to separate solvent. Each recovered solvent is recycled to the process.