A number of oxides are evaluated as candidates for use as``interphases'' in CMCs. Compounds studied are of the MXO4 type, i.e.phosphates, vanadates niobates, where M is a rare earth or yttriumion. These are assessed in terms of their thermal and chemicalstability and evidence of de-bonding in conjunction with selectedoxides considered as potential fibre/matrix combinations, after heattreatment at 1400 deg C, the target temperature for application ofoxide CMCs in gas- turbines. Methods of deposition of these compoundsonto commercially available woven oxide fibres are compared and anoptimised procedure for the in-situ deposition of NdPO4 onto 3M'sNextel 720 satin weave has been developed based on the use of animmiscible liquid bi-layer and aqueous solution precursors. Thefabrication of shaped components from oxide CMCs using infiltratedfabric pre-forms is also described. In addition, interphases havebeen successfully deposited on oxide substrates using RF-magnetronsputtering, yielding fine grained, uniform coatings.
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