Multilayered Fibre-Matrix Interphases Derived From the Electrophoretic Deposition of Ceramic Nano-Powders

Abstract

A significant challenge within the manufacturing of Ceramic Matrix Composites (CMCs) is the creation of the fibre-matrix interphase which enables the damage tolerant behavior of CMCs. Chemical vapour deposition (CVD) has been a highly successful approach for fabricating fibre-matrix interphases; however, CVD requires capital intensive facilities and hazardous precursors. This work examines electrophoretic deposition (EPD) as an alternative route for the production of fibre-matrix interphases. Four multilayered fibre-matrix interphases (SiC/Al2O3, BN/ZrO2, ZrC/85wt%Al2O3-15wt%ZrO2, and SiC/Si3N4/SiC) were produced through multi-staged electrophoretic deposition of ceramic nano-powders upon SiC fibre bundles. A 25-2 factorial design of experiments is utilized to explore the effect of different levels of the following variables: electric field strength, duration, surfactant, solids loading and binder. Following deposition of the fibre-matrix interphase the fibre bundles are thinly coated with a SiC matrix through a reactive melt infiltration technique. The resultant microcomposites are then subjected to tensile loading until failure to determine which coating and deposition combination are the most likely to yield favorable tensile properties. Additional microscopy is performed to determine the uniformity and thickness of the coatings. The results are then examined to evaluate the suitability of electrophoretic deposition as a production technique for fibre-matrix interphase coatings in CMCs.