Patented Dec. 26,‘ 1939 > 2,184,769“ UNlTED sTATss PATENT OFFICE ’ 2,184,769 ZIRCONIUM MAGNETIC ALLOY Peter l’opow~ Alexander, Marblehead, Masa, as slgnor to Metal Hydrides, Inc., Marblehead, Mass, a corporation of Massachusetts No Drawing. Application March '16,, 1937,‘ Serial No. 131,261 - 11 Claims‘. (01. 148-l3.1) This invention relates to magnetic alloys and treatmentmay be produced in any preferred or more especially to 'alloys of zirconium and metals suitable manner, for example, in accordance with of the iron group suitable for use as permanent the teaching of my copending application ?led magnets together with amethod of making the ‘ February 14, 1939, Serial No. 256,300. Thus a same. - > > mixture of‘ zirconium oxide and nickel oxide or It is well known in the art that the cohesive zirconium oxide and powdered metallic nickel force of the metals of the iron group may be is mixed with powdered calcium» hydride and greatly increased by alloying these metals with heated in a closed retort until the reduction of carbon, chromium, tungsten or aluminum. the oxides is completed. The heating is con 10 Permanent magnets have also been made of com tinued for a few hours until the diilusion of‘ 10 binations of the oxides of metals of the iron particles of reduced zirconium and nickel into group which under certain conditions have char one another and the‘ formation of particles of acteristics rendering them suitable for such use. zirconium-nickel alloy is completed. Some of these magnetic metals, however, are in- ' The series of binary alloys withzirconium de 415 capable of resisting the attacks of oxidizing at creasing from 95% to 35%, the ‘balance being mospheres while others do not withstand the nickel, do \not respond to the action of the mag- v action of corrosive media. The more general netic ?eld until they are heat" treated. I object of the present invention is to bring about This treatment consists in. subjecting the pow? alloys, especially those of metals of , the iron dered alloyto the temperatureof about 345° C. group, which not only have magnetic properties O As soon as any part of the charge reaches this 20 making them highly desirable for use as perma > temperature this part of the charge becomes, in nent magnets but whichware capable of resisting candescent and if placed in a dark place glows, the attacks of oxidizing atmospheres as well as indicating thatan exothermic reaction is taking withstanding the action of corrosive media. place. - Pure zirconium metal is one of themost corro -The glowing spreads {rapidly over the whole sion-resistant metals available at the present chargebut in a few seconds diminishes in in 25 time yet in pure state it is paramagnetic. Nickel tensity and ?nally disappears. This reaction is has high permeability, is resistant to a certain accompanied by the evolution of hydrogen oc degree to the corrosion-by-acid media, but-does cluded in the alloy, which .burns in contact with not have sufficient retentivity and cohesive air. - force. Both of these metals when heated above The weighing of the samples before and after 30 certain temperatures form oxides which are “glowing” showed practically no change in weight paramagnetic. The combination of zirconium indicating that the chemical'composition with and nickel with the amount of zirconium de the exception of the hydrogen content remained 35 creasing from 95% to 35%, the balance being substantially unchanged. Yet the magnetic nickel, forms alloys which do not respond to the properties of the alloys are changed radically by 35. action of a magnetic ?eld. When the amount of this heat treatment. The alloys readily respond zirconium is decreased below 35%, the alloy re to the action of the magnetic ?eld and have a sponds to a magnetic ?eld but is not suitable for high magnetic permeability and retentivity. use in the manufacture of permanent magnets. The powdered alloys with zirconium less than In accordance with the present invention ‘alloys 33% respond to the action of the magnetic ?eld 40 of zirconium and metals of the iron group, for even before the heat treatment. Yet when heat example nickel, are produced wherein the alloys ed to about 345° C. they exhibit the same phe respond readily to the magnetic ?eld even where nomenon of “glowing”, after which their mag 65 the amount of zirconium ranges from 35 to 95 netic permeability and-retentivity are greatly in 45 percent. “Moreover when ‘the amount of czir- . creased. ‘ conium is 40% or less the magnetic characteris The calcination of these powdered} alloys for a tics of the alloys! especially with respect to their short time does not seemto have noticeable in permeability and ' retentivity is 'so» markedly fluence either on their magnetic properties or on changed that the alloys form permanent mag their chemical composition. Yet prolonged cal nets having characteristics comparable to_ if not cination at the temperature of red heat results exceeding those of any alloy previously known“ in the gradual oxidation of the'alloy particles Primarily the invention depends on the dis; and the diminishing of the magnetic properties. covery by me that powdered alloys of zirconium If the calcination is continued for one or two 55 and‘nickel when subjected to a heat treatment, days, depending on the composition of the alloy, 55 more fully described hereinafter, acquire mag it is transformed entirely into a complex oxide netic properties which are radically di?erent with a complete loss of magnetic properties. than those characterizing the alloys before such The above alloys. especially those with a high treatment. ' perc'entageof zirconium are sufficiently resist w The powdered alloys subjected to the heat ant to the attack by dilute acids, even in ?nely 00 1 2 . 2,184,769 powdered state. fact is of especial impor powdered alloys in a'slightly oxidizing atmos tance since these alloys exhibit; high magnetic phere until the temperature of the alloy is above properties when prepared by the'above method 345° C. but below 800° C. anclthereafter discon which after reduction with calcium hydride in. tinuing the application of heat.' . volves leaching with dilute hydrochloric acid to 4. The method of making a magnetic alloy of O1 remove the calcium oxide. The zirconium-nickel zirconium and a metal, selected from a group alloys in a cast condition especially with zir honsisting of nickel, cobalt and iron, which com conium above 33% prepared by the usual fusion prises mixing the selected metal in powdered form method do not possess any of the above de with powdered zirconium‘ oxide and powdered scribed magnetic properties. 7 ‘ g calcium hydride, heating the mixture until the In preparing these zirconium magnetic alloys reduction of the'oxide by the calcium hydride is nickel may be replaced by'other metals of the complete and the particles of reduced zirconium iron group. Zirconium-iron or zirconium-cobalt and the metal diffuse into one another and there alloys exhibit similar magnetic properties tothe after subjecting the powdered alloy to a tem zirconium-nickel alloys. ' perature of' at least 345° C. but not exceeding ' 0n the other hand when in preparing these 800° C. . i binary alloys zirconium is replaced by other 5. The method of making a magnetic. alloy of metals of the zinconium group, for instance, by zirconium and a metal selected from a group titanium, the resulting titanium-nickel alloys do consisting of nickel, cobalt and iron, which com-. not exhibit the described magnetic properties. prises mixing the selected metal in powdered form 29 In .preparing my .zirconium-nickel magnetic with powderedv zirconium oxide and powdered alloys no special effort is made to eliminate the calcium hydride, heating the mixture until the last traces of other elements such‘ as carbon, reduction of the oxide by the calcium hydride is iron, manganese, tungsten or chromium. Also complete and the particles of reduced ‘zirconium their presence is not necessary. The zirconium and the metal diffuse-into one another and there 25 nickel alloys prepared from chemically pure ox after heating the powdered alloy in an atmos ides exhibit all the described magnetic proper phere containing oxygen to a temperature of at ties. Yet the addition of the third or fourth least 345° C. but not exceeding 800° C. , element to the binary alloys is not detrimental 6, The method of making a magnetic alloy of‘ and in some particular cases is even advan ' zirconium and a metal selected from a group con

tageous. . ' V sisting of nickel, cobalt and iron, which comprises The produced powdered alloys can be formed mixing the selected metal in powdered form with into bars or other desired forms by any methods powdered zirconium oxide and powdered cal well known to the art, such as pressing under cium hydride, heating the mixture until the re a hydraulic press at room or elevated tempera duction of the oxide by the calcium hydride is ture, sintering in the furnace, ,etc. 1 complete and the particles'of reduced zirconium - The described heat treatment can also be car- ' and the metal diffuse into one another and there ried out in the commercial vacuum of about 29 after heating the powdered alloy in a slightly inches of mercury or in the stream of commer oxidizing atmosphere to a'temperature of at least cially pure hydrogen, carbon dioxide or other 345° C. but. not exceeding 800° C. .40 suitable gas. The temperature ' of treatment 7. A permanent magnet formed of a powdered however, should be in these cases higher than alloy consisting of zirconium and a. metal se when heat treatment is'carried out in air in an lected from a group consisting of nickel, iron open crucible. “ . and cobalt, the zirconium content of; the alloy The modi?cations of my process of preparing ‘being not less than 5% or more than 40% and my magnetic alloys and their composition may said alloy being heat treated at a temperature occur to those skilled in the art but such as fall of substantially 345° C. . . _ within the scope of my invention are contem 8. A permanent magnet formed of a powdered plated by me as forming part of my invention. alloy consisting of zirconium and a metal se What I claim as new and desire to secure by lected from a group consisting of nickel, iron 50 Letters Patent of the United States, is: and cobalt,’ the zirconium content of the alloy 1. The herein described method of forming ' being not less than 5% or more than 40% and magnetic alloys of zirconium and a metal selected _ said alloy being heat treated at a temperature from a group consisting of nickel, iron and co of not less than 345° C. and not more than 'balt, which comprises producing a powdered ‘800° C. ~ alloy of the zirconium and selected metal and 9. A permanent magnet formed of a. powdered ' subjecting the powdered alloy to a temperature alloy consisting of‘ zirconium and any two metals of not less than 345°C. andnot more than 800° _C. selected from a group consisting of nickel, 'iron ' ’ 2. The herein described method of forming a and cobalt, the zirconium content of ‘the alloy magnetic alloy of zirconium and a metal selected, being notless than 5% and not more-than _40%, - from a group consisting of nickel, iron and co— and said alloy being heat-treated at a. tempera balt, which comprises producing a powdered ture‘of at least ‘345° C. but not more than 800° C. ' alloy of the. zirconium andselected'metal and‘ 10. A‘ permanent magnet in accordance ‘with - heating the powdered alloy in an atmosphere claim 9 in which nickel iii-amounts not less than containing oxygen until the temperature of the 5% or more than _40% is one of the selected alloy'is' above 345° C. but below 800° C. and metals, the balance being iron. - - . thereafter discontinuing the application of heat. 11. A permanent magnet in accordance wit -3.' The herein described method of forming a - claim 9 in which cobalt in amounts not less than magnetic alloy of zirconium arid a metal selected 5% 'or more than 30% is one of the selected from a group consisting of nickel, iron and co- - ‘metals. ~ . . ,4 70 belt, which _ comprises producing a powdered PETER; POPOW ALEXANDER. alloy of the zirconium and metal and heating the