| 摘要 |
PURPOSE:To provide a lighter weight and higher rigidity and to eliminate partial resonance by forming a nickel-boron film on the surface of an aluminum pipe base body. CONSTITUTION:A nickel-boron (Ni-B) film 7 is formed by an electroless plating method on the surface of an aluminum (Al) pipe base body 6 for a tone arm. The partial resonance is eliminated, resonance frequency is increased and the strength and rigidity are made about twice higher when the Ni-B film 7 is provided on the body 6 to 0.1mm. The Al pipe base body 6 which is subjected to a chromate treatment on the film 7 or is preliminarily formed thereon with the Ni-P film and is further formed thereon with the Ni-B film or is adhered with a polycarbonate resin film on the inside surface of the body 6 is equally effective. The excellent oscillation characteristic is obtd. |
