Spherical Sb/Sb2O3 composite nanoparticles similar to 80 nm in diameter were synthesized by innovated hybrid induction and laser heating (HILH). Under the irradiation of 80 kV electronic beams for 3 min, the aligned nanoparticles were welded into the Y-type nanorods, indicating their instability. Moreover, after annealed at >= 400 degrees C for 1 h in air, the Sb/Sb2O3 nanoparticles exhibit thermal instability. Their shape varies from the spherical nanoparticles, through the regular polygon nanoparticles, irregular polygon microparticles into the spear-like microparticles, as the annealing temperature increases from 400 to 600 degrees C. Beyond 500 degrees C, the Sb content inside them completely disappears. The metallic Sb inside the Sb/Sb2O3 nanoparticles is responsible for their instability. (c) 2005 Elsevier B.V. All rights reserved.