Air-stable magnetic materials and method

Claim 1

A PROCESS FOR COATING A METAL HAVING A MELTING POINT ABOVE 500*C ON COBALT-RARE EARTH ALLOY PARTICLES WITHOUT SIGNIFICANTLY DETERIORATING THEIR PERMANENT MAGNET PROPERTIES PRODUCING MAGNETICALLY AIR-STABLE PARTICLES EHICH COMPRISES PROVIDING PARTICLES OF COBALT-RARE EARTH ALLOY HAVING AN AVERAGE SIZE UP TO ABOUT 10 MICRONS, PROVIDING AN ORGANOMETHALLIC COMPOUND WHICH AT A TEMPERATURE BELOW 500*C DECOMPOSES AND YIELDS PRODUCTS OF DECOMPOSITION CONSISTING OF GASEOUS NON-METALLIC PRODUCT AND A METAL VAPOR, PLACING SAID COMPOUND AND SAID PARTICLES IN A SUBSTANTIALLY INERT ATMOSPHERE WHICH IS A FLOWING ATMOSPHERE OR A SUBSTANTIAL VACUUM, HEATING SAID ORGANOMETALLIC COMPOUND AT A TEMPERATURE BELOW 500*C AND SUBSTANTIALLY COMPLETELY DECONPOSITION AND A METAL DUCING SAID GASEOUS PRODUCT OF DECOMPOSITION AND A METAL VAPOR, CONTACTING THE RESULTING METAL VAPOR WITH THE COBALTRARE EARTH ALLOY PARTICLES DEPOSITING A COHERENT SUBSTANTIALLY UNIFORM METAL COATING WHICH AT LEAST ENVELOPS THE PARTICLES PROVIDING AN EFFECTIVE BARRIER TO THE ATMOSPHERE AND WHICH HAS NO SIGNIFICANT DETERIORATING EFFECT ON THIER MAGNETIC, PROPERTIES AND DIFFUSING AWAY THE NON-METALLIC GASEOUS PRODUCTS OF DECOMPOSITION, SAID ORGANOMETALLIC COMPOUND BEING USED IN AN AMOUNT WHICH ON DECOMPOSITION YIELDS A PARTIAL PRESSURE OF METAL VAPOR OF AT LEAST ABOUT 10-7 ATMOSPHERE AND PRODUCERS THE METAL IN AN AMOUNT RANGING FROM 1 PERCENT TO 5 PERCENT BY WEIGHT OF SAID COBALT-RARE EARTH ALLOY PARTICLES AND SAID DEPOSITED METAL HAVING A MELTING POINT ABOVE 500*C.