超高速プラズマ照射とレーザー超急冷による表面改質

Abstract

Plasma spraying experiments were conducted by using a rail gun. By supplying a pulsed high current of more than 100kA. W plasma jet of 1.9～5.0km/s in exit velocity and 200 atm in peak pressure was produced, Coating made by the plasma jet of W on a steel substrate was about 10μm in thickness. High speed spraying experiments were also conducted in the cases of W spraying to Al, Cu, PZS and Al_2O_3, Ti spraying to steel and Al, and AlTi spraying to steel and Cu. A nonequilibrium hard phase has been constructed in the surface layer of substrate. As another attempt, laser quenching method has been applied to prepare surface modification. Amorphous Fe_<78>B_<13>Si_9 ribbon was soldered on a stainless steel shaft and laser beam scanned the surface, expecting to reform amorphous Fe_<78>B_<13>Si_9 soft magnetic layer on the surface by rapid melting and quenching. Noncontact type torque sensor has been constructed by using this technique successfully.