Method for producing improved an anisotropic magent through extrusion

Abstract

A method for producing an improved anisotropic magnet through an extrusion process wherein the container involved in the extrusion process is first coated, on its internal surface, with a material to prevent the bonding of the interior surface to the particle charge to be extruded and, thereby, to prevent cracking due to tensile stresses. In addition, an improved anisotropic extrusion product, with enhanced magnetic properties, can be obtained by holding the temperature of the extrusion product at temperatures between 1000° F. and 1750° F. for between 1 and 10 hours.

What is claimed is:  
     
         1 . A method for producing an improved anisotropic magnet, said method comprising placing a particle charge of a composition from which said magnet is to be produced in a container, evacuating and sealing said container, heating said container and said particle charge and extruding said container and particle charge, wherein said container, prior to introduction of said particle charge, is coated on the internal surface of said container with a material to prevent the bonding of said interior surface of said container to said particle charge and, thereby, to prevent cracking due to tensile stresses.  
     
     
         2 . The method of  claim 1  wherein said material is an inert material selected from the group consisting of fused silica, high temperature refractory cement and boron nitride.  
     
     
         3 . The method of  claim 1  wherein said material is an inert material selected from the group consisting of zirconia, yttria, ceria, other rare earth oxides and combinations of zirconia, yttria, ceria and other rare earth oxides.  
     
     
         4 . The method of  claim 1  wherein said coating is applied as a paste.  
     
     
         5 . The method of  claim 1  wherein said coating is applied as a spray.  
     
     
         6 . The method of  claim 1  wherein said method further includes the step of subjecting the post extrusion product to a thermal treatment which consists of holding the temperature of said extrusion product at temperatures between 1000° F. and 1750° F. to obtain enhanced magnetic properties.  
     
     
         7 . The method of  claim 6  wherein said thermal treatment is applied for between 1 and 10 hours.  
     
     
         8 . A method for producing an improved anisotropic magnet with enhanced magnetic properties, said method comprising placing a particle charge of a composition from which said magnet is to be produced in a container, evacuating and sealing said container, heating said container and said particle charge, extruding said container and particle charge, and subjecting the post extrusion product to a thermal treatment which consists of holding the temperature of said extrusion product at temperatures between 1000° F. and 1750° F.  
     
     
         9 . The method of  claim 8  wherein said thermal treatment is applied for between 1 and 10 hours.