| 摘要 |
PURPOSE:To obtain a glass for ultrasonic delay line having remarkably low sonic speed, keeping good meltability of the glass, by using an SiO2-B2O3 glass containing large amount of B2O3. CONSTITUTION:The glass for ultrasonic delay line of the present invention has the following composition. 5-45wt.% SiO2, 30-85% B2O3, 0-20% Al2O3, 0-20% Li2O+Na2O+K2O+Rb2O+Cs2O, 0-45% MgO+CaO+SrO+BaO+ZnO+ PbO, etc., and 0-10% fluoride of at least one kind of metal element of the above metal oxide in terms of the total F2. Since the glass of the present invention is an SiO2-B2O3 glass containing large amount of B2O3, the sonic speed can be decreased while keeping T.C.D.T value (temperature coefficient of delay time near room temperature) and the glass has excellent meltability.
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