Investigation of sintering kinetics of ZnO by observing reduction of the specific surface area

Stevanović, Suzana; Zeljkovic, V.; Obradović, Nina; Labus, Nebojša

doi:10.2298/sos0703259s

Cited by 3 publications

(3 citation statements)

References 7 publications

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“…Values of calculated activation energies for the above-mentioned sintering mechanisms differ significantly from those calculated using the first model, although both models confirm the assumption that the sintering process includes two different mechanisms: surface and volume diffusion. Also, the results obtained within this paper are in great agreement with the results obtained during our previous experiment [9]. We studied the sintering kinetics of ZnO powder through specific surface reduction applying two models: Nicholson's and Hartman's.…”

Section: Resultssupporting

confidence: 88%

Influence of ZnO specific surface area on its sintering kinetics

Obradović

Stevanović

Zeljkovic

et al. 2009

Powder Metall Met Ceram

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The aim of this work is an investigation of isothermal sintering kinetics by observing the reduction of the specific surface area of ZnO. Zinc oxide powder is sintered isothermally in air for 5 to 120 min at temperatures from 400 to 900°C. The decrease in the specific surface area is observed as a function of temperature and sintering time. Models of Ristic-Jovanovic and German are applied in order to define the appropriate parameters. Information on the activation energy of sintering is obtained by the Arrhenius equation. The least square estimation (LSE) method was applied for determining optimum parameter values.

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Section: Resultssupporting

confidence: 88%

Influence of ZnO specific surface area on its sintering kinetics

Obradović

Stevanović

Zeljkovic

et al. 2009

Powder Metall Met Ceram

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“…When the xerogel is calcined at 500 • C or 700 • C, this treatment transforms the agglomerates into aggregates, which consequently significantly reduces the surface area and pore volume. When primary nanoparticles are combined into groups by interparticle bonding and sintering, the final assemblies are polycrystalline [37,38]. The Ce-ZnO samples exhibits the highest BET surface area among all synthesized materials, which is consistent with the SEM images (Figures 3 and 4), while the particles are uniform in shape and size.…”

Section: Resultssupporting

confidence: 82%

Photocatalytic Degradation of Rhodamine B Dye in Aqueous Suspension by ZnO and M-ZnO (M = La3+, Ce3+, Pr3+ and Nd3+) Nanoparticles in the Presence of UV/H2O2

2021

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In this study, nanoparticles of five photocatalytic systems based on pure zinc oxide and with rare earths ions M-ZnO (M = La3+, Ce3+, Pr3+ or Nd3+) calcined at 500 °C or 700 °C were synthesized and investigated as potential photocatalysts for the removal of dyes. The addition of rare earth ions causes a decrease in the bandgap of ZnO; therefore, it can be well used to improve the photocatalytic properties. The photocatalytic activity of the synthesized nanoparticles was evaluated by the degradation of Rhodamine B in the presence of H2O2 under ultraviolet illumination. The results indicate that all the synthesized nanoparticles show good dye degradation efficiency. The highest degradation efficiency was 97.72% for the Ce-ZnO sample calcined at 500 °C and was achieved in 90 min with an excellent constant of the dye degradation rate k = 0.0363 min−1 following a first-order kinetic mechanism. The presence of oxychlorides as secondary phases inhibits the rate of the photocatalytic reaction.

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“…Explanation of the atmosphere influence change on the microstructure lies in the fact that diffusion of the vacancies is faster than atomic species and their annihilation with oxygen present in air atmosphere is leading to closed porosity disappearance. The difference between micro and nano powder sintered compacts is that in micro powders [25,26] closed pores are from different origin. Closed porosity in nanopowders does not originate from inter powder particles pores as in micro powders, but from collected vacancies.…”

Section: Resultsmentioning

confidence: 99%

Influence of nitrogen and air atmosphere during thermal treatment on micro and nano sized powders and sintered TiO2 specimens

et al. 2014

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The influence of air and nitrogen atmosphere during heating on TiO2 nano and micro sized powders as well as sintered polycrystalline specimens was analyzed. Sintering of TiO2 nano and micro powders in air atmosphere was monitored in a dilatometer. Non compacted nano and micro powders were analyzed separately in air and nitrogen atmospheres during heating using thermo gravimetric (TG) and differential thermal analysis (DTA). The anatase to rutile phase transition temperature interval is influenced by the powder particle size and atmosphere change. At lower temperatures for nano TiO2 powder a second order phase transition was detected by both thermal techniques. Polycrystalline specimens obtained by sintering from nano powders were reheated in the dilatometer in nitrogen and air atmosphere, and their shrinkage is found to be different. Powder particle size influence, as well as the air and nitrogen atmosphere influence was discussed. [Projekat Ministarstva nauke Republike Srbije, br. OI172057 i br. III45014]

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Investigation of sintering kinetics of ZnO by observing reduction of the specific surface area

Cited by 3 publications

References 7 publications

Influence of ZnO specific surface area on its sintering kinetics

Influence of ZnO specific surface area on its sintering kinetics

Photocatalytic Degradation of Rhodamine B Dye in Aqueous Suspension by ZnO and M-ZnO (M = La3+, Ce3+, Pr3+ and Nd3+) Nanoparticles in the Presence of UV/H2O2

Influence of nitrogen and air atmosphere during thermal treatment on micro and nano sized powders and sintered TiO2 specimens

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