Investigation of the intra-particle sintering kinetics of a mainly agglomerated alumina powder by using surface area reduction
Yükleniyor...
Tarih
2006
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
An alumina precursor was prepared by the aluminium sulphate (0.20 M) and excess urea reaction in boiling aqueous solution. The precursor was calcined at 900 degrees C for 2 h and then delta-Al2O3 Powder having volumetric agglomeration degree of 80% was obtained. Cylindrical compacts having diameter of 14 mm were prepared under 32 MPa by axial pressing using oleic acid as binder. Each compact was fired isothermally at various temperatures between 950 and 1400 degrees C. The firing time was changed from zero to 2 h. The fired compacts were examined by scanning electron microscopy (SEM) and nitrogen adsorption techniques. The specific surface areas (S/m(2) g(-1)) of the samples were calculated using the Brunauer, Emmett, and Teller (BET) procedure. The rate constant (k) and mechanism-characteristic parameter (n) were obtained for different temperatures between 950 degrees C and 1150 degrees C from the application of the neck-growth sintering rate (NGRM) model on the surface area reduction data. An Arrhenius equation and the parameter n for the sintering were found in the forms of k = (7.648 x 106 h(-1)) exp (-186,234 J mol(-1)/RT) and n = 4.0 x 10(-7) T-3 - 1.7 x 10(-3) T-2 + 2.3 T- 1030.8 respectively. The parameter n changes in the interval 0.61 < n < 1.34 with rising temperature having maximum at about 1025 degrees C. Based on the SEM images and NGRM data, the intra-particle sintering was discussed. (c) 2006 Elsevier B.V. All rights reserved.
Açıklama
Onal, Muserref/0000-0002-1540-8389
Anahtar Kelimeler
agglomeration, alumina, sintering kinetics, surface area
Kaynak
Powder Technology
WoS Q Değeri
Q2
Scopus Q Değeri
Q1
Cilt
168
Sayı
1
Künye
closedAccess
