A New Approach of the -OH Content in Berlinite Crystals

✍ Scribed by J.M. Durand; A. Ibanez; A. Goiffon; E. Philippot

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 236 KB
• Volume: 109
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1994.1078

✦ Synopsis

In view of the numerous methods, often inconsistent, proposed to quantify the (\mathrm{OH}) content from IR measurements in the piezoelectric materials as quartz and (\mathrm{MXO}{4}(M=\mathrm{Al}, \mathrm{Ga}) and (\mathrm{X}=\mathrm{P}, \mathrm{As})) quartz-like crystals, we have reinvestigated this determination. This knowledge is very important, because it is closely related to piezoelectric properties, in particular the (Q) factor, which is drastically reduced by this impurity. After a brief overview of previous studies devoted to quartz and berlinite crystals, we develop a formula taking into consideration an anisotropic factor, (\gamma), for the (\mathrm{OH}) content distribution. This relation has been applied to IR measurements of a berlinite bar. Then, the (\mathrm{C}{\mathrm{OH}}) content can be directly estimated from the height, (K), of the (3300 \mathrm{~cm}^{-1}) absorption band: (\mathrm{C}_{\mathrm{OH} /(\mathrm{A}+\text { + })} \mathrm{ppm}=907 \mathrm{~K}) with an isotropic (\mathrm{OH}) distribution. 1994 Academic Press, Inc.