Synthesis
of
Ruby Powders
by
Self-Propagating Combustion Synthesis

 

Dr. A. Cuneyt Tas
Dept. of Metallurgical and Materials Engineering
Middle East Technical University
Ankara 06531
Turkey

 

Preliminary Lab-Report

 

     Aqueous solutions of chromium nitrate (Cr(NO3)3. 9H2O) and aluminum nitrate (Al(NO3)3.9H2O) in appropriate volumetric amounts, were used as the starting materials in the synthesis of "Ruby" (0.2 to 1 at% Cr) powders. Urea was used as the oxidation agent during the combustion synthesis. Glycine or carbohydrazide may be considered  as the alternative oxidation agents in this process.

     Crystal chemical aspects of the resulting powders were studied by Rietveld Analysis, as a function of the amount of Cr present in the crystal structure and the heating temperature (1250 to 1500°C).

     Morphological properties and the sintering behavior of the synthesized powders were investigated by the SEM (scanning electron microscopy) studies.
 

 

"SEM micrograph of Ruby powders heated at 1500°C"

 

The highly interesting grain morphology observed warrants further research..