US1982012A - Process for manufacturing hard objects in silicidized carbon or other similar substances - Google Patents

Description

Nov. 27, 1934. A. L. MINGARD 1,982

PROCESS FOR MANUFACTURING 'HARD OBJECTS IN SILICIDIZED CARBON OR OTHER SIMILAR SUBSTANCES Filed April 20, 1932' A VJ...,

Patented Nov. 27, 1934 1,982,012 rnocnss ron MANUFACTURING mum OBJECTS IN SILICIDIZED CARBON OTHER SIMILAR SUBSTANCES Aurele Louis Mingard, Lausanne, Switzerland Application April 20, 1932, Serial No. 606,490 In France May 11, 1931 lclaim.

The object of this invention is a process for manufacturing very hard objects, particularly grinding stones, in silicidized carbon or other very hard materials.

i The process consists essentially in transforming objects of any shape, made of carbon, into another very hard substance particularly into silicidized carbon, without altering their shape and by chemical reaction at high temperature.

I The crucible in which the reactions take place is filled with a mixture of substances capable of reacting upon each other at the temperature produced by an electric arc struck between electrodes. By the influence of this are and as a result of the 5 chemical reactions between the substances forming the charge, metallic vapors are produced,

which reach a certain pressure, forming a pocket with the are in the center, and which pocket gradually increases in volume until the objects to be transformed, and which at the commencement of the operation were embedded in the charge, are enclosed within the pocket charged with metallic vapors, without having changed their position, and are subjected to the action of these vapors, until the transformation into a very hard material particularly silicidized carbon, is completed.

The transformation is preferably produced in a furnace consisting of a crucible l of any desired ,0 shape, containing a lining of refractory bricks.

This furnace is placed either vertically or horizontally and may be of the tilting type. It is provided with electrodes 2 of carbon or other material capable of resisting high temperatures. l6 These electrodes may be placed into the furnace in any position with respect to the furnace, and at any variable position with regard to each other. They can, for instance, be placed along the center line of the furnace in line with each other and L0 at any distance from each other. Each electrode is fitted on the end inside the furnace with a piece of carbon 3 of any suitable shape, cylindrical, coneshaped etc. The object or objects of carbon 4 to be transformed are attached to the electrodes [5 in any suitable manner, along their center line for instance if they are cylindrical. The other electrode may also be provided with a similar object or an object of different shape to the one attached to the first electrode. so In the case of a body of carbon in the form of a grinding wheel, the body may be mounted on the electrode by means of the axial bore formed therein. When so mounted the body is held in place on the electrode by friction between the i5 bore in the body and the electrode.

.bon, into silicidized carbon or other material proceeds in the following manner.

The furnace is charged with a mixture of sub-' stances capable of producing by chemical reaction at high temperature the transformation of the objects of carbon into silicidized carbon or other very hard substances.

As an example of such substances forming the charge the following mixture is mentioned:

For obtaining silicidized carbon:

' Parts Silica I 30 Carb l the charge in the furnace, liberating from one of the constituents silicon vapors, or other vapors according to the nature of the charge.

This reaction may be represented as follows:

These vapors reach a certain pressure and rapidly form around the are a pocket 5 with the arc in the center. The pocket gradually increases in volume until the objects of carbon which it.

is desired to transform are enclosed within this pocket. These objects are then subjected to the action of. metallicfvapors of silicon or other elements and are transformed into silicidized carbon or as the case may be into other very hard materials with carbon as a base, without changing in shape or position in the furnace and without passing through any other physical changes. The objects may then be removed from the furnace'and the operation can be repeated.

I claim:

A method of producing grinding wheels comprising positioning a wheel formed 01' carbon on one of a pair of electrodes, surrounding the elec- 5 trodes and carbon wheel with a charge of silica and carbon, electrically energizing the electrodes and striking an are between them, maintaining the vapor phase products of conversion formed

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