Study of ZrN-AlN formation solid-phase reaction in a nitrogen atmosphere during microwave heating

This paper is devoted to the discussion of the experimental results on the solid-phase synthesis of the nitride material ZrN-AlN. A mixture of powders of metallic zirconium and aluminum nitride was heated by means of microwave radiation in a nitrogen atmosphere for 90 minutes. Phase composition by sample volume and electron microscopy of the surface were studied to confirm the solid-phase reaction of zirconium with aluminum nitride. Thermodynamic calculations showed that several possible processes happen at once and lead to the formation of the nitride material ZrN-AlN in a nitrogen atmosphere. Experimental results showed a relatively low content of zirconium nitride (32.8 mol.%) and a significant content of metallic zirconium residues (8.8 at.%) in the upper layers of the sample despite contact with the gas phase. While in the sample volume, the conversion of metallic zirconium to nitride was almost complete (the content is 74.9 mol.%). Experimental observations have shown that, due to microwave heating, the formation of characteristic coral-like growths on the surface of particles with the concentration of chemical impurities, due to the purity of the initial reagents, is evident.