| Popis: |
Temperature dependence of internal friction and dynamic shear modulus for boron anhydride (B2O3) and boron suboxide (B6O) have been investigated at frequencies of 1–10 Hz and over the temperature range 80–900 K. Absolute shear modulus for boron suboxide at 80 and 400 K was 0.9 and 0.85 GPa, respectively. Relaxation maximum of internal friction, accompanied with shear modulus defect had activation energy of 0.8 eV, and frequency factor of ∼1.1012 s−1.Measruements of absolute values of boron suboxide shear modulus at various temperatures showed deviations from linear decrease above 670 K. In the internal friction spectrum at temperatures of 410 and 700 K the maxima of origin have been revealed. At temperatures of 595 and 650–700 K an intense maxima of internal friction and shear modulus defects were observed.Many of the relaxation and hysteretic processes have been discussed accounting on the possiblity of formation of point defects (oxygen vacancies, unbonded boron atoms), split dislocations and polysynthetic twins in the (001) rhombohedral planes, lowering down the local symmetry in the boron suboxide crystal structure. |
