Abstract: The present invention provides a thermal history sensor having a plurality of substrates positioned adjacent to an item. The substrates include different compositions, such that the substrates respond to thermal exposures with different changes in electrical conductivity or magnetic permeability. By measuring the electrical or magnetic properties of the substrates following thermal exposure, information about the thermal history may be obtained.

Abstract: An improved method for coating ceramic fibers and woven cloths of ceramic fibers is disclosed, wherein the ceramic fibers are thoroughly wetted with precursors in a solution before the precursors react to form a coating by heterogeneous nucleation and growth. The fibers are then rinsed and fired and, where desired, the process may be repeated in stages to increase the coating thickness as desired. This method is amenable to operation in both the batch and continuous modes. This flexible method reduces both the cost and time of producing ceramic matrix composites (CMCs).

Abstract: An improved thermal history sensor having multiple polymeric substrates with unique compositions is disclosed. By positioning the sensor adjacent to an item subject to thermal stressors, each of the polymeric substrates react with a different rate of crystallization and thus yield a specific measure of infrared (IR) absorption spectra, for example. By comparing these measurements for each polymeric substrate, a thermal history fingerprint may be obtained. This thermal history fingerprint may then be compared to baseline data to yield information about the item, such as the expected remaining useful lifetime of the item.

Abstract: An improved thermal history sensor having multiple glass ceramic substrates with unique compositions is disclosed. By positioning the sensor adjacent to a component subject to thermal stressors, each of the glass ceramic substrates react with a different rate of nucleation and crystal growth and thus yield a specific measure of opacity. By comparing these values representing the opacity for each glass ceramic substrate, or thermal history fingerprint, to baseline data, information about the expected remaining useful lifetime of the component may be obtained.