加速器用真空導波管フランジガスケットの電解研磨

Abstract

We developed electropolishing process of aluminum using vibrating blade agitator that can provide pit-free surface. The vibrating blade agitator is such an agitator that has blades vertically attached to an axis vibrating up and down at dozens of cycles a second.Pitting is caused by hydrogen gas bubbles generated at cathode during electropolishing. Those bubbles often stick on the parts' surface and make pits there. They stick more heavily when larger plane parts are electropolished in viscous electrolytes.We electropolished aluminum gasket for linear accelerator. The gasket is 135 mm in diameter, 2 mm thick and has some holes. Pulsating stream produced by vibrating blades kept hydrogen gas bubbles away from the gasket and avoided them sticking on the surface during electropolishing.Polished surface was highly smooth and pit-free. Surface roughness was diminished from Ra= 0.09 μm to Ra=0.03 μm, and oxide layer of 200 nm thick was formed on the surface after electropolishing.