Iron-neodymium-boron permanent magnet alloys prepared by consolidation of amorphous powders

Claim 1

A method for preparing a fine grained iron-neodymium-boron bulk-shaped alloy comprising the steps of: forming an alloy melt having the following composition: Fe a Co b Nd c R d M e B f wherein Fe, Co, Nd and B are iron, cobalt, neodymium and boron respectively, and R is an element selected from the group consisting of lanthanum, yttrium, cerium, dysprosium, terbium, gadolinium, and praseodymium and mixtures thereof, and M is an element selected from the group consisting of aluminum, silicon, germanium, niobium and gallium and mixtures thereof, wherein a=65-84, b=0-25, c=5-20, d=0-10, e=0-5 and f=3-10 respectively with the proviso that the sum (a+b+c+d+e+f)=100, adding 0.3 to 3 weight percent of at least one diboride selected from the group consisting of zirconium diboride, titanium diboride and tantalum diboride, to said melt of alloy, depositing said melt against a rapidly moving quench surface adapted to quench said melt at a rate in the range of approximately between 10 5 to 10 7 ° C./second and form a rapidly solidified filament, ribbon or particulate of said alloy characterized predominantly by a single amorphous structure, comminuting said ribbon, filament or particulate into a powder, said powder having an average particle size of less than 60 mesh and consisting of platelets having a thickness of less than 0.1 millimeter, each platelet being defined by an irregularly shaped outline resulting from fracture, and consolidating said powder into a bulk shape consisting of fine grained crystalline phases using hot extrusion.

Claim 2

A method for preparing a fine grained iron-neodymium-boron bulk-shaped alloy comprising the steps of: forming an alloy melt having the following composition: Fe a Co b Nd c R d M e B f wherein Fe, Co, Nd and B are iron, cobalt, neodymium and boron respectively, and R is an element selected from the group consisting of lanthanum, yttrium, cerium, dysprosium, terbium, gadolinium, and praseodymium and mixtures thereof, and M is an element selected from the group consisting of aluminum, silicon, germanium, niobium and gallium and mixtures thereof, wherein a=65-84, b=0-25, c=5-20, d=0-10, e=0-5 and f=3-10 respectively with the proviso that the sum (a+b+c+d+e+f)=100, adding 0.3 to 3 weight percent of at least one diboride selected from the group consisting of zirconium diboride, titanium diboride and tantalum diboride, to said melt of alloy, depositing said melt against a rapidly moving quench surface adapted to quench said melt at a rate in the range of approximately between 10 5 to 10 7 ° C./second and form a rapidly solidified filament, ribbon or particulate of said alloy characterized predominantly by a single amorphous structure, comminuting said ribbon, filament or particulate into a powder, said powder having an average particle size of less than 60 mesh and consisting of platelets having a thickness of less than 0.1 millimeter, each platelet being defined by an irregularly shaped outline resulting from fracture, and consolidating said powder into a bulk shape consisting of fine grained crystalline phases using hot extrusion.