Isothermal dynamic thermal diffusivity studies of the reduction of NiO and NiWO(4) precursors by hydrogen
2011 (English)In: International Journal of Materials Research - Zeitschrift für Metallkunde, ISSN 1862-5282, Vol. 102, no 11, 1336-1344 p.Article in journal (Refereed) Published
Thermal diffusivity measurements of uniaxially cold pressed NiO and NiWO(4) were carried out in a dynamic mode in order to monitor the kinetics of hydrogen reduction of the above-mentioned materials using a laser flash unit. The calculated activation energy was found to be higher than that for chemically-controlled reaction obtained earlier by thermogravimetry. The difference has been attributed to physical changes occurring along with the chemical reaction. The activation energy of sintering of the products was evaluated to be 33 and 36 kJ.mol(-1) for NiO and NiWO(4), respectively. Thermal conductivities were calculated taking into consideration the change in heat capacity considering the compositional and the structural changes with the progress of the reaction. The potentiality of the laser-flash method as a complementary technique to thermogravimetry in understanding the mechanism of gas solid reactions is discussed.
Place, publisher, year, edition, pages
2011. Vol. 102, no 11, 1336-1344 p.
Thermal diffusivity, Gas-solid reactions, Reduction by hydrogen, Ni-W-O system, Laser flash
IdentifiersURN: urn:nbn:se:kth:diva-58823DOI: 10.3139/146.110591ISI: 000297955000004OAI: oai:DiVA.org:kth-58823DiVA: diva2:474167
QC 201201092012-01-092012-01-092012-03-23Bibliographically approved