摘要:
A magnetized or unmagnetized body (10) of a permanent magnet material is heated in a pattern by a laser beam (18) to a temperature sufficient to lower the magnetic coercivity of selected heated regions of the pattern and then exposed to a magnetic field to magnetize or to re-magnetize the selected heated regions. A pattern guide (30) is used in the process to densify the pattern. In the process, energy (18) is directed through the pattern guide (30) and onto the selected regions, whilst the pattern guide (30) prevents or minimizes heating of unselected portions of the body (10). Magnets so produced can have very high pole density, digital encoding and analog patterns having gradually varying local field strength.
摘要:
A method is disclosed for heating a cold worked sheet of superplastically formable metal composition to recrystallize its microstructure to a formable condition and/or to heat the sheet to a temperature for an immediate forming operation. The sheet is placed between two electrical resistance heated platens maintained at a suitable temperature for recrystallizing and/or heating the metal sheet through its side surfaces. In a preferred embodiment a critical gap is maintained between the platens and the sheet to permit rapid conductive heating of the expanding sheet without marring its surfaces.
摘要:
A permanent magnet (10) is heated in a pattern by a laser beam (18) to a localized temperature above the Curie point therof or a temperature sufficient to reduce the magnet coercivity thereof sufficiently for the field of the magnet (16') or an external field to re-magnetize the pattern in the reverse direction. Magnets so produced can have very high pole densities, digital encoding and analog patterns having gradually varying local magnetic field strengths.
摘要:
In a preferred embodiment, graphite fibres 66 are grown by natural gas pyrolysis on an iron-base metal surface 16 initially bearing a relatively thick oxide.
摘要:
A method is disclosed for heating a cold worked sheet of superplastically formable metal composition to recrystallize its microstructure to a suitably formable condition and further to heat the sheet to a temperature for an immediate forming operation. The method utilizes a combination of hot air convection heating and infrared radiation to rapidly accomplish the heating. High temperature infrared heating elements provide most of the energy during an initial high heating rate phase and then those elements are shut off and heating is completed with controlled temperature hot air to prevent overheating of the sheet metal.
摘要:
A magnetized or unmagnetized body (10) of a permanent magnet material is heated in a pattern by a laser beam (18) to a temperature sufficient to lower the magnetic coercivity of selected heated regions of the pattern and then exposed to a magnetic field to magnetize or to re-magnetize the selected heated regions. A pattern guide (30) is used in the process to densify the pattern. In the process, energy (18) is directed through the pattern guide (30) and onto the selected regions, whilst the pattern guide (30) prevents or minimizes heating of unselected portions of the body (10). Magnets so produced can have very high pole density, digital encoding and analog patterns having gradually varying local field strength.
摘要:
Non-magnetized permanent magnet material (10) is heated in a pattern by a laser beam (18) to a localized temperature above the Curie point thereof or a temperature sufficient to reduce the coercivity thereof sufficiently for an external magnetic field (16) to magnetize the pattern in the direction of the magnetic field (16). Magnets so produced can have very high pole densities, digital encoding and analog patterns having gradually varying local magnetic field strengths. Alternating pole magnets of this type can be used for stepper motor magnets.