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Influence of oxygen on thermal stability of nano crystalline aluminum studied by positron annihilation spectroscopy

XIANBAO SONG1, ZHU WANG1,* , PENGFEI TAI1, FEGSHOU TIAN1, LIANGLIANG LIU1

Affiliation

  1. College of Physics and Technology, Laboratory of nuclear solid physics, Wuhan University, Wuhan 430072, P. R. China

Abstract

The thermal stability of nanocrystalline (nc) Al has been studied by means of positron lifetime spectroscopy and X ray diffraction (XRD), prepared by compacting nanoparticles under high pressures. Those nanopar ticles were produced by the flow levitation (FL) method [1] and the arc discharge (DC) method. Effect of oxide at nanoparticle surface on structure stability of nc Al was investigated especially in this experiment. The positron lifetime spectroscopy result s reveal that vacancy clusters in grain boundaries are dominant positron traps in both samples. The mean grain size of the sample consisting of nanoparticles with partially oxidized surfaces is almost unchanged after aging at 150 for 84 h, with that of the sample consisting of pure nc Al increasing. The partially oxidized surfaces of nanoparticles hinder the growth of grain when aging at 150 ℃℃, which implies that the oxide stabilizes the microstructure of the nanomaterials. The ef fect is beneficial for nc materials to keep excellent properties..

Keywords

Positron annihilation, Thermal stability, Nanocrystalline material, Defect, M icrostructure.

Citation

XIANBAO SONG, ZHU WANG, PENGFEI TAI, FEGSHOU TIAN, LIANGLIANG LIU, Influence of oxygen on thermal stability of nano crystalline aluminum studied by positron annihilation spectroscopy, Optoelectronics and Advanced Materials - Rapid Communications, 9, 5-6, May-June 2015, pp.704-708 (2015).

Submitted at: Feb. 12, 2015

Accepted at: May 7, 2015