Ruby Powders
Self-Propagating Combustion Synthesis


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


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 1500C).

     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 1500C"


The highly interesting grain morphology observed warrants further research..