An indirect model for sintering thermodynamics

Sarikaya Y., ÖNAL M.

TURKISH JOURNAL OF CHEMISTRY, cilt.40, sa.5, ss.841-845, 2016 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 40 Sayı: 5
  • Basım Tarihi: 2016
  • Doi Numarası: 10.3906/kim-1603-61
  • Dergi Adı: TURKISH JOURNAL OF CHEMISTRY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, TR DİZİN (ULAKBİM)
  • Sayfa Sayıları: ss.841-845
  • Anahtar Kelimeler: Alumina, nanoporosity, sintering, thermodynamics, ALUMINA, POROSITY, KINETICS
  • Ankara Üniversitesi Adresli: Evet

Özet

A model was proposed and used to calculated the changes in enthalpy (Delta H degrees), entropy (Delta S degrees), and Gibbs energy (Delta G degrees), as well as equilibrium constant (K) relating to the sintering of alumina compacts. Specific nanopore volume (V) of the compacts was assumed as a thermodynamic variable. A hypothetical equilibrium constant (K-h) and corresponding Gibbs energy (Delta G(h)(degrees),) were calculated depending on the V value measured after each sintering. The thermodynamic relationships with the SI units were respectively evaluated for the initial-stage (i) sintering between 1000 and 1200 degrees C and final-stage (f) sintering between 1200 and 1600 degrees C in the following form: AG(i)(degrees) = -RT In K-i - Delta H-i(degrees) - T Delta S-i(degrees) = 161,042 - 110.5T and AG(f)(degrees); = -RTIn K-f = Delta H-f(degrees) T Delta s(f)(degrees) = 39,000 - 47.5T.