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Sintered Silicon Iron Magnetic Material

IP.com Disclosure Number: IPCOM000097087D
Original Publication Date: 1962-May-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Ambs, HD: AUTHOR [+2]

Abstract

The sintered silicon-iron material is used as a soft magnetic material having magnetic properties sufficient to give quality performance. Substantially pure, soft, carbon-free, electrolytic iron powder is mixed with a 17% silicon master alloy to yield silicon in the desired proportion of 1 to 4%. Zinc stearate is added for internal lubrication. This mixture is worked in the following manner: 1. Cold shaping to briquettes of the desired shape at pressures of 85,000 to 110,000 PSI. 2. Pre-sintering at a temperature below that at which any substantial diffusion of silicon in iron occurs, between 1600 and 1700 degrees F. The pre-sintering is carried out under strongly reducing conditions for a period of 15 to 45 minutes. 3. Repressing at pressures of 85,000 to 110,000 PSI.

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Sintered Silicon Iron Magnetic Material

The sintered silicon-iron material is used as a soft magnetic material having magnetic properties sufficient to give quality performance. Substantially pure, soft, carbon-free, electrolytic iron powder is mixed with a 17% silicon master alloy to yield silicon in the desired proportion of 1 to 4%. Zinc stearate is added for internal lubrication. This mixture is worked in the following manner:
1. Cold shaping to briquettes of the desired shape at pressures of 85,000 to 110,000 PSI.
2. Pre-sintering at a temperature below that at which any substantial diffusion of silicon in iron occurs, between 1600 and 1700 degrees F. The pre-sintering is carried out under strongly reducing conditions for a period of 15 to 45 minutes.
3. Repressing at pressures of 85,000 to 110,000 PSI. This increases the density to 92 to 96% of the theoretical.
4. Sintering at temperatures of 2300 to 2400 degrees F in a strongly reducing and decarburizing atmosphere for periods of 1 to 2 hours. This temperature is above the melting range of the 17% silicon master alloy, which forms a liquid phase and promotes diffusion and homogeneity of the article.
5. Coining to dimensions and annealing to develop magnetic properties.

A typical material is:

2 1/2% Sintered Silicon Iron Alloy

Density - 7. 34 gm/cc (95% of theoretical)

U.T.S. - 58,210 PSI

Ductility - 16.4% in 1

Magnetic Properties

B max. (gauss) - 14,130

Br (gauss from sat.) - 12,070

Hc (oersteds from sat.)...