| 摘要 |
PURPOSE:To make a diaphragm homogeneously have a quick propagation speed and a suitable internal loss, by forming a homogeneous nitriding layer on both surfaces of a titanium foil diaphragm. CONSTITUTION:A nitriding substance is formed on the surface of a titanium foil by executing a vacuum suction, raising a temperature in a ratio of 10 deg.C/min, leading nitrogen gas into a furnace as soon as a temperature reaches 820 deg.C, and heating (in a nitrogen air current) for one hour at 820 deg.C. Comparison of characteristics in a tweeter of diaphragms of titanium 2 and titanium nitride 1 which have been formed in this way become as whon in the figure, and in case of titanium nitride 1, a smooth characteristic can be obtained. In this way, a nitride layer being homogeneous and having constant thickness is formed, therefore, a physical property of the diaphragm takes a constant value, and an acoustic characteristic of a loudspeaker is remarkably improved. Also, since the nitriding substance is a porous layer consisting of a columnar polycrystal, a large internal loss is obtained. |
