Experimental elastic moduli of the pure vitreous inorganic oxides SiO2, GeO2, P2O5, B2O3, and As2O3, are compared with simple theoretical models of elastic deformation involving the use of available estimates for the anion‐cation (first order) stretching force constants. On the basis of this comparison it is concluded that all of these glasses are essentially three‐dimensionally‐connected ring structures: the average ring size, in each case, being similar to the sizes found in corresponding crystalline forms of these oxides.

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Ultrasonic testing is a promising :\DE technique for ceramic structural components. The lifetime of such components is controlled by defects and flaws. The critical flaw sizes for high performance ceramics are 25 pm and to detect such small flaws, the frequency of the transducers has to be > 30 :vi Hz [1-4]. Such transducers are usually made from ZnO, LiNb03, LMN composites [5], and PVDF piezoelectric materials However there are no reports of aluminium nitride (All\') films being used for such applications In this paper the piezoelectric and dielectric properties of All\' films and their application to high frequency devices are discussed and compared with the conventional materials.

Ultrasonic testing is a promising :\DE technique for ceramic structural components. The lifetime of such components is controlled by defects and flaws. The critical flaw sizes for high performance ceramics are 25 pm and to detect such small flaws, the frequency of the transducers has to be > 30 :vi Hz [1-4]. Such transducers are usually made from ZnO, LiNb03, LMN composites [5], and PVDF piezoelectric materials However there are no reports of aluminium nitride (All\') films being used for such applications In this paper the piezoelectric and dielectric properties of All\' films and their application to high frequency devices are discussed and compared with the conventional materials.