The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 03, 1991
Filed:
Feb. 12, 1990
Kaplesh Kumar, Wellesley, MA (US);
Anthony Petrovich, Tewksbury, MA (US);
The Charles Stark Draper Laboratory, Inc., Cambridge, MA (US);
Abstract
Method and apparatus for forming rare-earth magnets and magnet precursors of fine particle sized metal alloy powders with a high degree of metal to metal intimacy and homogeneity in the particle to particle metal composition. Salts of the desired metals which may include or be selected from zirconium, samarium, iron, cobalt, copper, neodymium and boron with nitric acid in a water based solution are atomized through a nozzle, which may be ultrasonic, into fine mist droplets form metal oxide particles which condense through a heated, atmospheric environment furnace. The furnace temperature is in a range of 600.degree. to 1150.degree. C. and causes decompositon of the metal salts along with their oxidation, driving off the liquid and nitrogen components along with other carrier materials. A very fine sized powder, typically micron dimension size powder of metal oxides, in which each particle represents a homogeneous proportion of the desired metal components, is collected in the bottom of the furnace. These fine particle metal oxide powders are subsequently reduced to metal alloy powder particles of similar homogeneity in the metal proportions. The reduction reaction typically utilizes calcium hydride in a hydrogen atmosphere to convert the metal oxides to metal alloy particles. The metal alloy powder is then aligned, compacted, densified and magnetized to produce magnets of high magnetic performance.