TEM study of the composition of the interstitial phase in an oil-well cement clinker

The interstitial phase of an oil-well cement production clinker was examined by analytical transmission electron microscopy. The predominant interstitial component was a ferrite of varying composition, the Fe: Al ratio varying from a low value to 2, and values most commonly in the range O·7-2. A substantial variation in composition sometimes took place over quite short distances. Displacement faults were found in the ferrite, and these appeared to be associated with relatively iron-rich regions of the ferrite. Small regions of C₂S, MgO and non-cubic C₃A were also found in the interstitial phase of the clinker.