ISSN:
1551-2916
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Maschinenbau
,
Physik
Notizen:
Elastic and mechanical properties such as Young's modulus E, Poisson's ratio ν, Debye temperature θD, Vickers hardness Hv, fracture toughness Kc, and fracture surface energies γf of yCuOx·(100−y)P2O5 glasses (y= 45, 50, 55) with different copper valence states, i.e., R(Cu+) = Cu+/(Cu++ Cu2+), at room temperature (humidity 64%) have been examined. The following features have been found: (1) the glass transition temperature (218–434°C), Hv (2.7–4.4 GPa), E (50.6–78.2 GPa), and θD (358–434 K) decrease largely with increasing R(Cu+); (2) the mean atomic volume, Kc (0.56–1.14 MPa·m1/2), and γf (1.9–11.2 J·m−2) tend to increase with increasing R(Cu+); (3) 50CuOx·50P2O5 glasses with R(Cu+) = 0.42 and 0.55 have a high resistance against crack formation in Vickers indentation tests and no crack is observed in the 45CuOx·55P2O5 glass with R(Cu+) = 0.57 under an applied load of about 98 N. The results demonstrate that elastic and mechanical properties of yCuOx·(100−y)P2O5 glasses depend strongly on the copper valence state and the CuOx/P2O5 ratio. The unusal mechanical and elastic properties of copper phosphate glasses are well explained qualitatively by considering unique oxygen coordination and bonding states of Cu+ ions, i.e., lower coordination number and more covalent bonding compared with Cu2+ ions.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1111/j.1151-2916.2001.tb01021.x
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