Rolling Mill
Ductile alloy can be rolled, either while hot or at room temperature, into continuous strips. The Stanat Mill located in the Technology Center has been completely refurbished and upgraded with digital gauging and tensioning controls. Dimensions that can be cold rolled are 0.125" thick down to 0.002" and a maximum width of 5.25". Hot rolling of slabs from 1.500" thickness is also feasible.
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Crushing/Pulverizing
Two large and one small jaw crushers can reduce 2.5" square by 1.5" thick or smaller blocks into small fragments either in air or an inert atmosphere. A disc mill reduces small chunks into a coarse powder, typically -30 mesh (less than 590 microns) while under nitrogen or argon atmospheres.
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Attrition
Four attritors are used to reduce coarse powder to a fine size. Two attritors are recirculating; two are non-recirculating. Three attritors operate with an inert gas blanket. Various liquids have been used to form the slurry in the mill including hexane and water. Materials which have been successfully milled to an average particle size as low as 2 microns include samarium cobalt, neodymium-iron-boron, alnico and hard ferrite.
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Pressing
Three presses are utilized: an isostatic press and two compaction presses. The isostatic press is capable of pressing blanks of 2.5" OD by 16" long to a pressure of 55,000 psi. One compaction press is configured for axial (parallel) pressing. The second press is arranged for transverse (perpendicular) pressing. Parallel pressing means that the particle orienting magnetic field is applied in the same direction as the applied press pressure. Transverse means the applied field is at right angles to the press pressure.
Tooling used for isotropic (non-aligned) powders can be ferromagnetic. Die sets have been used to press samples at over 150 tons per square inch. Tooling used for pressing aligned powder must be either non-ferromagnetic or contain magnetic materials in very specific locations. These tools are restricted to lower compaction pressures, typically 55 tons per square inch.
Aligning fields are provided by DC power supplies that generate over 18 kOe of field strength in the working die volume.
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Sintering
Two vacuum furnaces serve sintering requirements. Each has the capability to sinter in full vacuum (less than 5x106 torr) or with one or more process gases at sub-atmospheric pressure. These furnaces are fitted with a residual gas analyzer for measurement of gases evolved during the sintering process. Both furnaces are connected to a process data logging system.
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Finishing Operations
The Technology Center has a well-equipped model shop. Equipment includes a CNC diamond saw, CNC diamond surface grinder, lathes, drill press, and numerous metalworking machines. Finishing processes include machining, painting, gluing and testing.
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Treating Ovens
Three ovens are arranged for low temperature treating of materials in a vacuum or in process gases.
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