• Korean Chemical Engineering Research
• /
• v.44 no.3
• /
• pp.235-242
• /
• 2006

Spray pyrosysis is a process to prepare particles and films by evaporating and decomposing droplets of precursor solutions in the order of 1-10 micrometer in diameter. Key elements of the spray pyrolysis process include precursor, solvent, droplet generator, and reactor. Various combination of these 4 elements produces wide range of particles and films. In general. the current status of the spray pyrolysis technology is not quite promising for commercial success. However, this process will be feasible to produce multicomponent functional materials of controlled morphology. In this paper, current status of the spray pyrolysis technology is introduced with the emphasis of production of fluorescence particles.

• Proceedings of the KAIS Fall Conference
• /
• 2001.05a
• /
• pp.47-48
• /
• 2001

본 연구의 목적은 폐 구리염화물 용액을 원료로 사용하여 분무열분해 공정에 의해 평균입도가 1㎛이하이며 입도분포가 균일하고 치밀한 조직을 나타내는 미립의 구리산화물 분말을 제조하는데 있다. 또한 본 연구에서는 분무열분해 공정에 의해 생성되는 분말의 특성에 영향을 미치는 반응 온도, 원료용액의 유입속도, 분위기 기체 및 공기의 유입속도, nezzle tip 크기 및 원료용액의 농도 등의 반응인자들의 영향을 검토하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.7 no.2
• /
• pp.324-333
• /
• 1997

Porous alumina specimens with 80~92% relative densities were prepared from ultrasonic spray pyrolyzed alumina Powders by sintering at $1600^{\circ}$~ $1700^{\circ}C$. The exaggerated grain growth appeared to high sintering temperature and long soaking time. The microstructural development during sintering was investigated using image analysis. In the study of grain growth kinetics for sintering for spray prolyzed alumina powder, the activation energy for normal grain growth was 386.77 kJ/mol.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.29 no.1
• /
• pp.12-18
• /
• 2019

The spherical $SiO_2$ powders were synthesized by the scaled-up ultrasonic pyrolysis (USP). The aqueous $SiO_2$ sol, which contained 20~30 nm $SiO_2$ particles, was used as a precursor for the scaled-up USP. The effects of the USP operating conditions and precursor conditions were systematically investigated, including reaction temperature, gas flow rate, and the concentration of $SiO_2$ sol on the morphologies of synthesized $SiO_2$ particles. the synthesized $SiO_2$ particle showed a pseudo-crystal phase, spherical morphology, and a smooth surface. The size of the spherical $SiO_2$ particle decreased as both reaction temperature increased and precursor concentration decreased. In addition, the synthesized $SiO_2$ particle size was increased by increasing the gas flow rate. Lastly, the scaled-up USP was compared with the lab-scale USP based on the same process conditions. Due to a short retention time in the reaction tube during the USP process, the $SiO_2$ particle synthesized via the lab-scale USP showed a larger particle size.

• Journal of the Korean Applied Science and Technology
• /
• v.31 no.4
• /
• pp.694-702
• /
• 2014

The micron-sized ITO(indium tin oxide) particles were prepared by spray pyrolysis from aqueous precursor solutions for indium, and tin and organic additives solution. Organic additives solution with citric acid(CA) and ethylene glycol(EG) were added to aqueous precursor solution for Indium and Tin. The obtained ITO particles prepared by spray pyrolysis from the aqueous solution without organic additives solution had spherical and filled morphologies whereas the obtained ITO particles with organic additives solution had more hollow and porous morphologies with increasing mole of organic additives. The micron-sized ITO particle with organic additives was changed fully to nano-sized ITO particle whereas the micron-sized ITO particle without organic additives was not changed fully to nano-sized ITO particle after post-treatment at $700^{\circ}C$ for 2 hours and wet-ball milling for 24 hours. The size of primary ITO particle by Debye-Scherrer formula and surface resistance of ITO pellet were measured.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2007.11a
• /
• pp.80.1-80.1
• /
• 2007

• 기계와재료
• /
• v.20 no.4
• /
• pp.57-66
• /
• 2009

• Korean Chemical Engineering Research
• /
• v.43 no.4
• /
• pp.517-524
• /
• 2005

Barium titanate ($BaTiO_3$) particles were prepared by spray pyrolysis from spray solution containing organic additives. The effects of the type and amount of organic precursors on the crystal structure and morphology of the $BaTiO_3$ particles were investigated. It was found that the morphology of $BaTiO_3$ particles before and after calcination depended on the type of organic additives such as citric acid, ethylene glycol and polyethylene glycol. Among these organic additives, citric acid was the most effective to prepare $BaTiO_3$ particles with nano-structured morphology consisting with uniform size nanometer particles after calcination. It was also found that the phase transformability of the metastable cubic phase to the tetragonal one during calcination could be improved by increasing the content of citric acid in the spray solution. As a result, $BaTiO_3$ particles prepared from spray solution containing high concentration of citric acid had good tetragonality, uniform and fine size, and high BET surface area after calcination. $BaTiO_3$ particles prepared by spray pyrolysis had nanometer size and uniform morphology after simple ball milling process.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2002.12a
• /
• pp.114-115
• /
• 2002

다성분계 세라믹스에 대하여 초미립 및 나노 분말을 제조하기 위해 공침법, 비정질 citrate법, 무기 금속염을 이용한 sol-gel법, 분무 열분해법 등과 같이 비교적 단순한 공정이면서 입도 분포가 좁고 재현성이 우수한 구형의 초미립 또는 나노 분말의 제조에 적합한 방법들이 많이 연구되고있다[1-3]. 분무 열분해법은 출발물질로 용액을 사용하고 미세한 액적(droplet)을 초음파 분무 후 열분해 하여 분말을 합성하는 방법으로, 입자의 조성이 균질하고 구형의 형상을 갖는 우수한 결정상을 얻을 수 있다. (중략)

• Korean Chemical Engineering Research
• /
• v.43 no.1
• /
• pp.80-84
• /
• 2005

Nano-sized $Y_2O_3:Eu$ phosphor particles were prepared by ultrasonic spray pyrolysis. The effect of polymeric precursor and lithium carbonate flux on the morphology and luminescence characteristics of nano-sized $Y_2O_3:Eu$ phosphor particles was investigated. When using the spray solution containing both the polymeric precursor and the flux, the $Y_2O_3:Eu$ particles with spherical shape and micron size were turned into nano-sized $Y_2O_3:Eu$ phosphor particles during the post-treatment at high temperature. The mean size of $Y_2O_3:Eu$ phosphor particles was affected by the contents of polymeric precursors and lithium carbonate flux, and preparation temperature. The as-prepared particles by spray pyrolysis at high temperature from solution containing high contents of polymeric precursors had good photoluminescence intensity under vacuum ultraviolet after post-treatment above $1,000^{\circ}C$. The prepared nano-sized $Y_2O_3:Eu$ phosphor particles had comparable photoluminescence intensity under vacuum ultraviolet light with that of the commercial $Y_2O_3:Eu$ phosphor particles prepared by solid state reaction method.