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US 6,348,265 B1Granted
Phosphate coated iron powder and method for the manufacturing thereof
AssigneeHöganäs AB
InventorsPatricia Jansson, Lars-Åke Larsson
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AssigneeHöganäs AB
InventorsPatricia Jansson, Lars-Åke Larsson
Estimating the term…
The invention concerns a novel low oxygen powder comprising particles of a base powder consisting of essentially pure iron having an insulating oxygen- and phosphorus-containing barrier. The oxygen content of the new powder is at most 0.2% by weight higher than the oxygen content of the base powder, and the ratio O:P is between 30 and 1, preferably between 15 and 2 and most preferably between 10 and 3 as measured by the ESCA method. The invention also concerns a new method of preparing an iron-based powder comprising the steps of preparing a base powder consisting of a water atomized iron powder or a sponge iron powder, subjecting the mixture to treatment with a solution of phosphoric acid in an organic solvent and drying the obtained mixture, whereby the solution of phosphoric acid is sprayed on the base powder while being mixed.
A low oxygen powder comprising particles of a base powder consisting essentially of pure iron having an insulating oxygen- and phosphorus-containing barrier, the oxygen content of the powder being at most 0.2% by weight higher than the oxygen content of the base powder, the ratio O:P being between 15 and 2 as measured by the ESCA method and the barrier having a thickness of at most 100 nm as measured by the AES method.
A low oxygen powder comprising particles of a base powder consisting essentially of pure iron having an insulating oxygen- and phosphorus-containing barrier, the oxygen content of the powder being at most 0.2% by weight higher than the oxygen content of the base powder, the ratio O:P being between 15 and 2 as measured by the ESCA method and the barrier having a thickness of at most 100 nm as measured by the AES method, the powder being a water-atomized or sponge iron powder, and a majority of the particles having a particle size above 10 μm.
A low oxygen powder comprising particles of a base powder consisting essentially of pure iron having an insulating oxygen- and phosphorus-containing barrier, the oxygen content of the powder being at most 0.2% by weight higher than the oxygen content of the base powder, the ratio O:P being between 15 and 2 as measured by the ESCA method, the barrier having a thickness of at most 100 nm as measured by the AES method, and the barrier consisting essentially of oxygen and phosphorus, the powder being prepared by spraying a phosphoric acid solution on the powder particles.
Dependencies are inferred from the claim text.