PURPOSE: To manufacture a lightweight boron diaphragm for acoustics with a high specific elastic modulus by sticking a Cr layer to a thin substrate having parallel upper and lower faces and roundish right and left ends, forming a boron layer by chemical vapor deposition, and mechanically peeling off the boron layer in a temp. dropping process.
CONSTITUTION: A Cr layer having 0.1W3μm thickness is stuck to a thin substrate having opposite and parallel upper and lower faces and roundish right and left ends. The substrate is made of Ta, Nb, Ti, W or Mo, and it is formed by rolling or other method. A boron layer is then formed by chemical vapor deposition. The desirable thickness of the boron layer is about 50W100μm. Next, the substrate is quenched from a high temp. such as about 1,000°C to room temp., and in the quenching process the boron layer is peeled off the substrate at a stroke with a peeling sound. Thus, etching can be eliminated, and a diaphragm of only boron is obtd.
AOKI MASAKI
YOSHIDA SHIGERU
