The standard molar enthalpies of formation of alpha -Si sub 3 N sub 4 and beta -Si sub 3 N sub 4 by combustion calorimetry in fluorine, and the enthalpy of the alpha -to- beta transition at the temperature 298.15K

The standard molar enthalpies of formation Delta sub f H sub m exp o of alpha -Si sub 3 N sub 4 and beta -Si sub 3 N sub 4 have been determined by fluorine combustion calorimetry: Delta sub f H sub m exp o (Si sub 3 N sub 4 , cr, alpha , 298.15 K)= -(828.9plus /minus3.4) kJmultmol exp -1 and Delta s...

Full description

Saved in:
Bibliographic Details
Published in:Journal of materials research 1997-12, Vol.12 (12), p.3203-3205
Main Authors: O'Hare, P A G, Tomaszkiewicz, I, Seifert, H J
Format: Article
Language:English
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The standard molar enthalpies of formation Delta sub f H sub m exp o of alpha -Si sub 3 N sub 4 and beta -Si sub 3 N sub 4 have been determined by fluorine combustion calorimetry: Delta sub f H sub m exp o (Si sub 3 N sub 4 , cr, alpha , 298.15 K)= -(828.9plus /minus3.4) kJmultmol exp -1 and Delta sub f H sub m exp o (Si sub 3 N sub 4 , cr, beta , 298.15 K)= -(827.8plus/minus2.5) kJmultmol exp -1 . These results indicate that the enthalpy of the alpha -to- beta transition, approximately (1plus/minus4) kJmultmol exp -1 , is negligible within experimental uncertainty.
ISSN:0884-2914