Abstract
The application of a magnetic field was investigated in order to prolong the service life of Metal-on-Metal artificial hip joint, in which the bearing material was Co-Cr-Mo alloy. It has been clarified that the magnetic field had a chemical effect on wear process in ferromagnetism materials; the chemical effect seemed to be acceleration of oxidizing the bearing surfaces. Pin-on-Plate and Sphere-on-Plate wear machines was used with test specimens, in which a permanent magnet was inserted. Each specimen was alternative of an artificial head or a socket. It was confirmed that the magnetic field dramatically reduced the wear of the Co-Cr-Mo alloy that was paramagnetic material. The inserted position of the magnet, which could expect the magnetic field, was limited. It was necessary that the magnetic flux in the space from the magnet to the rubbed point was not turbulence to reduce the wear.
