SIMS, EDX, EELS, AES, XPS study of interphases in nicalon fibre-LAS glass matrix composites. I. Composition of the interfaces

Secondary ion mass spectroscopy (SIMS) and energy dispersive x-ray spectroscopy (EDX) were used to analyse interphases which develop at the fibre/matrix interface during fabrication of SiC nicalon fibre-LAS (Li sub 2 O, Al sub 2 O sub 3 , SiO sub 2 ) or LAS+Nb sub 2 O sub 5 glass matrix composites. SIMS was performed on fibres extracted from composites by dissolution of the matrix in hydrofluoric acid (HF). The composition of the interphases which remain on the fibre periphery was studied using sputter-depth profiling. EDX analysis of the interphases was performed on nicalon-LAS+Nb sub 2 O sub 5 composite cross-sections. These investigations show that in both composites the reaction products at the fibre/matrix interface consist of a carbon layer and a silicate phase, rich in oxygen, located between the C layer and the fibre core. The analyses also demonstrate the efficiency of SIMS for analysing compositional changes in the near surface of fibres of small diameter.