Design and Synthesis of Metal-Organic Precursors to Aluminosilicates

Abstract

Diketonate aluminum alkoxides were prepared and allowed to react with acetoxyalkylsilanes. The conversion of the aluminosiloxanes thus obtained to aluminosilicates at 450°C was demonstrated. These aluminosiloxane ceramic precursors are glassy, oligomeric materials which readily dissolve in organic solvents to give viscous solutions ideal for casting films. Films of the metal-organic compounds prepared in this manner yield monolithic, crack-free aluminosilicate films directly on thermal curing, with a thickness limit of 3000Å for single crystal silicon wafer substrates. These aluminosilicate films have been found to be effective anticorrosion barriers for various metal substrates. The chemistry of this organoaluminosilane system and the nature of the aluminosilicate films obtained has been investigated using a variety of chemical and physical methods. The results of this investigation will be described and the possible advantages of this direct conversion process over the sol-gel method as a means of obtaining aluminosilicate films will be discussed.