Abstract: A surface treatment for a R-TM-X type of permanent magnet comprising the steps: Etching the magnet with nitric acid having a concentration of 0.2 to 10 vol %, then etching the magnet with a mixture of oxygenated water having a hydrogen peroxide concentration of 0.2 to 10 vol % and acetic acid having a concentration of 10-30 vol %, and next plating the magnet with a copper plating initially followed by a nickel plating. R represents an element or a mixture of rare earth elements, TM is mainly composed of iron and transition elements other than iron and X represents one or more of a mixture of elements to enhance the coercivity of the magnet. This improvement of the magnet material itself improves the corrosion resistance of the protective film on the magnet surface.

Abstract: A magnetically anisotropic magnet substrate is coated with at least one layer of nickel plating followed by a chromate layer. The chromate top layer improves the corrosion resistance of the coated magnet substrate. In a preferred embodiment, the layer of nickel plating includes a first layer of a non-bright nickel plating followed by a second layer of a semi-bright nickel plating. One embodiment adds a copper under-layer below the nickel plating.

Abstract: A fishing line release mechanism has a permanent magnet positioned within a housing with the poles of the magnet arranged to draw a magnetic release plate toward, or into contact with, the magnet. The release plate has a buttonlike configuration with a central aperture which enables the plate to be threaded by a fishline. When a fishline threaded through the magnetic plate aperture is looped several times around the plate and the plate is then positioned in proximity to the permanent magnet, the line cannot unreel until considerable tension is applied to it. The tension limit can be preset. When the preset limit is reached, the buttonlike magnetic plate springs away from the permanent magnet to release the fishline to further control by the reel.

Abstract: A fishing line release mechanism has a permanent magnet positioned within a housing with the poles of the magnet arranged to draw a magnetic tripping member into the housing through an opening in which the tripping member is positioned. The tripping member includes at least one belaying pin which is arranged with its axis across the opening in the housing when the member is in a position where it is near, or in contact with, the permanent magnet. When sufficient tension is applied to a fishing line wrapped around the belaying pin at the time the tripping member is closest to the permanent magnet, the member is pulled away from the magnet and the axis of the belaying pin is lined up with the direction of pull of the fishing line to release the line over the free end of the pin. The release mechanism may include means for variably positioning the magnet with respect to the tripping member as well as a line guide through which a line may be drawn to the belaying pin or pins.

Abstract: An organic binder or lubricant in a pressed or compacted green body formed of cobalt-rare earth intermetallic particles is substantially removed from the green body before the carbon can react with the rare earth during sintering. This is accomplished by exposing the green body to a temperature of about 100.degree. to 300.degree.C in a hydrogen-containing atmosphere. The hydrogen reacts with the organic binder or lubricant which allows the resulting organic molecules to volatilize from the green body. The green body is then sintered after which it is cooled to room temperature.

Abstract: The invention covers the use of reactive hydrogen-containing atmospheres in the sintering and heat-aging of cobalt-rare earth intermetallic products.

Abstract: A transducer device such as a loudspeaker or microphone has a U-shaped core of magnetically permeable material with attached pole pieces defining a gap and a stationary electrical coil around the core. A permanent magnet is positioned for movement through the central portion of the gap as directed by a variable magnetic field within the gap. The permanent magnet has diagonally positioned poles of like magnetic orientation to provide a north-south pole combination facing one of the pole pieces and a complementary south-north pole combination facing the other pole piece.