Thermal diffusivity/conductivity of MgAlON-BN Composites
2006 (English)In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 37, no 4, 615-621 p.Article in journal (Refereed) Published
Thermal diffusivity and heat capacity of MgAlON and MgAlON-BN composites were measured in the temperature range of 25 degrees C to 1300 degrees C using a laser flash technique and a differential scanning calorimeter (DSC) technique, respectively. Based on these measurements, effective thermal conductivity of the composites was calculated using the values measured earlier in the same substance. The experimental effective thermal conductivity results of the composites containing different BN contents were found to show the similar trend, which decreased rapidly with increasing temperature below 900 degrees C followed by a slow decrease with further increasing temperature. This can be explained by the fact that thermal conduction in both components, MgAlON and BN, was dominated by phonons. The phonon mean free path decreased with increasing temperature, limited by the characteristic length between two neighboring atoms. The BN addition has significant influence on the effective thermal conductivity. The effective thermal conductivity of the composites containing BN exhibited a small degree of anisotropy with respect to preferred orientation of the BN phase. The degree of anisotropy of the composites increased with increasing BN content, which is particularly pronounced at the higher BN additions. An equation suitable for the present composites has been derived based on Luo's model. The model was slightly modified in the present article. The predicted values calculated by the model were in good agreement with experimental results.
Place, publisher, year, edition, pages
2006. Vol. 37, no 4, 615-621 p.
conductivity, resistance, ceramics
Metallurgy and Metallic Materials
IdentifiersURN: urn:nbn:se:kth:diva-5481DOI: 10.1007/s11663-006-0045-4ISI: 000239590300012ScopusID: 2-s2.0-33747452376OAI: oai:DiVA.org:kth-5481DiVA: diva2:9861
Uppdaterad från "In press" till published: 20100929.
QC 201009292006-03-152006-03-152010-09-29Bibliographically approved