Measurement Of Fibre Coating Thickness Variation

The thickness of a fibre coating may vary significantly along a fibre, and the average thickness may vary between fibres. Coating bridges and fins between close packaged fibres and crusting of coating around the perimeter of a fibre tow or cloth are some features that contribute to thickness nonuniformity. Such features have generally been described subjectively. However, quantitative and reproducible thickness nonuniformity measurements are desirable so that the effects of such nonuniformity on properties of ceramic matrix composites can be evaluated. Parameters that may sufficiently characterise coating thickness nonuniformity and methods for measuring those parameters are presented and discussed.