Synthesis and characterization of nanocrystalline iron aluminide particles

In this work, we report the synthesis of intermetallic FeAl nanoparticles u sing the laser vaporization controlled condensation technique. Nanoparticle s of iron aluminides are expected to enhance the room temperature ductility and the high temperature strength of these materials. The nanoparticles ha ve an average particle diameter between 6 and 9 nm. Measurements of the d-s pacing from X-ray (XRD) and electron diffraction studies confirm that the n anoparticles have the same crystal structure (B2) as the bulk FeAl. High-re solution TEM reveals that the nanoparticles consist of a crystalline core e ncased within a approximate to1 nm amorphous layer formed upon the exposure of the particles to air. XPS results indicate that the nanoparticles have an Al-rich surface composition, which supports the assumption that the surf ace coating is Al oxide. The FeAl oxide nanoparticles prepared in the prese nce of O-2 have the hercynite FeAl2O4 composition and exhibit a different X RD pattern from that of the surface-oxidized FeAl nanoparticles. The curren t results demonstrate that, by controlling the experimental conditions, it is possible to prepare a variety of intermetallic nanoparticles with select ed size, morphology and composition. These particles can; serve as the buil ding blocks for advanced, high performance materials for several industrial and technological applications. (C) 2000 Elsevier Science Ltd. All rights reserved.