A basic study on the solid-state nitriding of aluminum by mechanical alloying using a planetary ball mill

Nitrogen dispersed amorphous aluminum powders were synthesized by high energy grinding using a planetary ball mill under N-2 atmosphere at room temperature. The modes of amorphization and recrystallization during the grinding were investigated by means of X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The grinding process can be classified into three stages, i.e. agglomeration, disintegration and homogenization. During the disintegration stage, an amorphous phase was formed and N-2 was supposed to diffuse into the aluminum. Recrystallization of N-2 dispersed amorphous aluminum powders was also studied. By annealing the final ground product in air and in vacuum at 1373 K for 3600 s, the particles were recrystallized to AlN/Al2O3 and AlN/Al composite, respectively.