Why use non-magnetic gasket to fix the magnetic ring on the end face of the hydraulic cylinder piston?

Linear displacement sensor in cylinder

Magnetism, like electricity, follows the path of low resistance. The large and flat surface of the steel hydraulic cylinder piston provides an irresistible way for the magnetic line of force of the magnetic flux. Moreover, because the magnetic ring can only provide so much "power", most of the magnetic field strength will eventually lead to insufficient magnetic energy at the displacement sensor to ensure normal operation.

Magnetoelastic displacement sensors rely on magnets as azimuth symbols. In a hydraulic cylinder, the magnet is usually in the form of a ring, which is connected to the outside of the piston. Because the piston is almost always made of ferrous metal (i.e. steel), it is important to use non-magnetic materials as gaskets so that the magnet does not directly touch the piston surface.

Article source: magnetostrictive displacement sensorhttp://www.delysensor.com