| 摘要 |
PURPOSE:To make a plating layer composite, to increase an internal loss and to improve the rigidity by forming the plating layer, where grains of metal and ceramic are scattered, at front and reverse surfaces of a diaphragm-like base made of a carbon fiber reinforced synthetic resin board. CONSTITUTION:After a base 1 formed with a carbon fiber reinforced synthetic resin board is subjected to degrease and pretreatment, it is dipped in a plating bath, and plating layers 2 and 3 are formed on the front and reverse surface thereof. The composition of the plating bath is 9.0-9.2% nickle, 8-10% phosphorus. Moreover, silicon carbide is used as a scattered fine grain 4, and its content in the plating layers 2 and 3 is set to 10-20%. As a result, the rigidity of a diaphragm and propagation speed are improved, whereby the propagation of a higher order frequency sound can be possible. Moreover, by making the plating layer composite, an internal loss is increased, and a frequency characteristic is smoothened. |
