Abstract
Positron annihilation spectroscopy (oPs lifetime, coincidence Doppler broadening techniques) was employed for defect studies of “Ti”-based nanocomposites prepared by high-energy ball milling. It was found that size of nanoscopic holes is reduced with increasing milling time in H2 /He atmosphere and also probability of Ps formation in holes decreases.
At the same time the Ti content in the vicinity of holes increases. A simple explanation of these observations was suggested.
The effect of filling the nanoscopic pores with hydrogen is enhanced in TiH2 milled with h-BN or B in He atmosphere. Sufficiently long milling time leads to a similar size distribution of nanoscopic holes in Ti/h-BN and Ti/B, despite the fact that it differs substantially in the initial powders, however, density of nanoscopic holes in Ti/B is significantly lower than in Ti/h-BN