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The self-propagating high temperature synthesis approach was applied to synthesize amorphous boron nanopowders in argon atmospheres. For this purpose, we investigated the characteristics of a thermally induced combustion wave in the B 2 O 3 + α Mg system(α = 1.0-8.0) in an argon atmospheres. In this study, the exothermic nature of the B 2 O 3 -Mg reaction was investigated using thermodynamic calculations. Experimental study was conducted based on the calculation data and the SHS products consisting of crystalline boron and other compounds were obtained starting with a different initial molar ratio of Mg. It was found that the B 2 O 3 and Mg reaction system produced a high combustion temperature with a rapid combustion reaction. In order to regulate the combustion reaction, NaCl, Na 2 B 4 O 7 and H 3 BO 3 additives were investigated as diluents. In an experimental study, it was found that all diluents effectively stabilized the reaction regime. The final product of the B 2 O 3 + α Mg system with 0.5 mole Na 2 B 4 O 7 was identified to be amorphous boron nano-powders(< 100 nm).