A composition providing thermal, corrosion, and oxidation protection at high temperatures is based on a synthetic aluminum phosphate, in which the molar content of aluminum is greater than phosphorus. The composition is annealed and is metastable at temperatures up to 1400.degree. C.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
 The United States government has certain rights to this invention pursuant to Air Force Office of Scientific Research contract no. F49620-00-C-0022 and Department of Energy contract no. DOE DE-AC05-84OR21400-1DX-SY067V, both with Applied Thin Films, Inc.