Abstract: Metal organic chemical vapor deposition (MOCVD) is used to form a layer of a metal oxide on the surfaces and within the pores of a porous ceramic material. The metal oxide is formed from one or more inexpensive metal organic precursors which permeate the pores of the substrate as a vapor. Surface reactions on the heated substrate convert the metal organic precursors to their metal oxide. The technique has particular utility in creating catalysts with very large surface areas and in providing a protective coating on ceramic materials that prevents or reduces damage from hostile environments. In a preferred embodiment, aluminum isopropoxide, [(CH.sub.3).sub.2 CHO].sub.3 Al, and titanium ethoxide, Ti(C.sub.2 H.sub.5 O).sub.4, are used simultaneously or successively as precursors to generate a Al.sub.2 TiO.sub.5 coating on a porous ceramic substrate such as SiC or porous refractory cement candle filters.

Abstract: Thin film interference filters consisting of alternating layers of tantala and silica suitable for high temperature use on electric lamps have been made by heat treating at 550.degree.-675.degree. C. before using the filters at high temperature. Tungsten halogen lamps made with such heat treated filters have been thermally cycled for thousands of cycles at 900.degree. C. with no film loss and with satisfactory optical performance.