| 摘要 |
PURPOSE:To obtain a new acoustic vibrating material by using a 1st film made of materials consisting of a high Young's modulue and a high specific gravity and a 2nd film made of boron carbide which is coated and formed on the 1st film. CONSTITUTION:Boron B is selected as the actual material for the 1st film. If the 1st film is formed with boron B, the 1st and 2nd films hardly peel off even if the manufactured vibrating material vibrates because the Young's modulue and specific gravity of the 1st film are similar to those of boron carbide B4C for the 2nd film. Besides, since they hardly produce the difference in terms of propagation at acoustic velocity the deterioration of acoustic velocity and that of responsiveness, both of which are caused by multiplexing layer, can be prevented. For manufacturing the 2nd film, basically a boron single element is evaporized, and gaseous hydrocarbon such as acetylene and methane is made into plasmas. Then the boron element and a carbon element are chemically reacted in the plasma to synthesize B4C. It is accelerated under a high electric field, piles up on the surface of the required basic material to form a B4C film.
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