Quantitative Aspects of 27Al MAS NMR of Calcium Aluminoferrites

Abstract

²⁷Al MAS NMR spectra of synthetic calcium aluminoferrites, Ca₂Al_xFe_2−xO₅ with x = 0.93, 1, 1.33, reveal only a few percent of the expected intensity for the ²⁷Al central transition, indicating that the calcium aluminoferrite phase in Portland cements can barely be observed by ²⁷Al MAS NMR. This result supports the use of ²⁷Al MAS NMR for quantitative analysis of the tricalcium aluminate phase in Portland cements.