Obtaining of Al-AlN nanocomposite based on SHS-AZ aluminum nitride nanopowder

Abstract

Method of azide self-propagating high-temperature synthesis (SHS-Az), using sodium azide as a nitriding reagent, was used for obtaining the nanopowder of aluminum nitride from precursor - sodium hexafluoroaluminate. The product of burning the mixture of Na3AlF6 + 3NaN3 after water rinsing consisted of micro - and nanoparticles of AlN (65%), as well as any salt Na3AlF6 (35%). This product of SHS-Az was mixed with copper powder and pressed into a briquette of nanopowder master alloy Cu-4%(AlN+35%Nа3АlF6), which was successfully introduced into aluminium melt at a temperature 850оС. The salt Nа3АlF6 in the product of combustion played a role of flux during introducing into the aluminum melt and was not included in the final composition of the composite alloy. The microstructure of the obtained cast composite aluminum alloy with the calculated composition of Al-1.2%Cu-0.035%AlN showed that the reinforcing particles of AlN of different sizes, including nanoparticles, are distributed mainly along the grain boundaries of the aluminum alloy.