Silicon Alloy Steel

Abstract

Pure silicon is a brittle insulator and, with addition of doping elements, performs as a semiconductor. It has found widespread use in computer integrated circuits as well as other semiconducting devices used in communication, electrical switching and power control. Silicon has also been used in solar collectors as active photovoltaic devices. The present application discloses formation and use of certain silicon alloys that take advantage of silicon's relatively low density near 2.33 grams per cubic centimeter and high melting temperature of 1,410° C. Alloys prepared with two to six percent boron, beryllium or mixtures thereof are strong and tough. Silicon steel containing near 2 percent alloying boron is hard while silicon alloys containing near 6 percent boron are tough and more flexible.

Claims

1. A process for formation of silicon steel alloy comprising melting together silicon with selected 2 to 6 percent boron in the temperature range comprising 1,400° C. to 1,800° C. in a suitable crucible in an inert atmosphere.

2. A process for formation of silicon steel alloy comprising melting together silicon with selected 2 to 6 percent beryllium in the temperature range comprising 1,200° C. to 1,600° C. in a suitable crucible in an inert atmosphere.

3. A process for formation of silicon steel alloy comprising melting together silicon with selected 2 to 6 percent boron, up to 2 percent of manganese for toughness and up to 0.5 percent sulfur for corrosion resistance in the temperature range comprising 1,400° C. to 1,800° C. in a suitable crucible in an inert atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0008] Pure silicon is brittle and not suitable for use as a construction material. Addition of additives comprising boron and beryllium, in a concentration range comprising 2 to 6 percent, to pure silicon form alloys with surprisingly good mechanical characteristics. These alloys are light weight in that they have densities of less than 2.7 grams per cubic centimeter. Once produced, they can be cut and formed like rigid steel.

[0009] Boron silicon alloys can be prepared by a number of methods, the simplest being from finely divided pure elements melted under an inert atmosphere. Blending a selected concentration comprising 2 to 6 percent finely divided elemental boron with a majority of finely divided elemental silicon, loading into a clean alumina crucible, moving into a furnace, carefully degassing and purging with an inert atmosphere during the entire heating process produces the desired alloy upon cooling. For example, a silicon steel alloy is formed by heating a uniform mixture containing 4.5 percent of finely divided 99% pure elemental boron and 95.5 percent of finely divided 99.5% pure elemental silicon, contained in a suitable crucible in an inert atmosphere, at 1,470° C. until completely molten. Upon cooling a strong, malleable steel alloy is evident.

[0010] Beryllium silicon alloys can be prepared by blending a selected concentration comprising 2 to 6 percent finely divided elemental beryllium with a majority of finely divided elemental silicon, loading into a clean alumina crucible, moving into a furnace, carefully degassing and purging with an inert gas atmosphere during the entire heating process produces the desired alloy upon cooling. For example, a uniform mixture containing 4.5 percent of finely divided 99% pure elemental beryllium and 95.5 percent of finely divided 99.5% pure elemental silicon, contained in a suitable crucible, is heated in an inert atmosphere at 1,350° C. until completely molten. Upon cooling a strong, malleable steel alloy is formed.

EXAMPLES OF CHEMICAL CONVERSION

[0011] Specific examples of boron or beryllium silicon alloy compositions are disclosed.

Example A: Boron Silicon Alloy Steel

[0012] A uniform mixture containing 1.125 grams of finely divided 99% pure elemental boron and 23.875 grams of finely divided 99.5% pure elemental silicon, contained in a suitable crucible, was heated in an inert atmosphere at 1,470° C. until completely molten. Upon cooling a silver-gray colored steel alloy was found to be strong and malleable but not brittle. Its density was 2.69 grams/cubic centimeter.

Example B: Beryllium Silicon Alloy Steel

[0013] A uniform mixture containing 1.075 grams of finely divided 99% pure elemental beryllium and 23.925 grams of finely divided 99.5% pure elemental silicon, contained in a suitable crucible, was heated in an inert atmosphere at 1,350° C. until completely molten. Upon cooling the steel alloy was found to be strong and malleable but not brittle.