GB2340507A

GB2340507A - Electromagnetic centrifugal alloying

Info

Publication number: GB2340507A
Application number: GB9817242A
Authority: GB
Inventors: David Philip Abraham Kessler
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-08-08
Filing date: 1998-08-08
Publication date: 2000-02-23
Also published as: GB9817242D0

Abstract

Apparatus and method for combining two or more substances comprising a chamber containing at least two molten substances to be combined, at least one of said substances being ionised. The chamber is rotated rapidly, causing the denser substance to accumulate at the periphery of the circle of rotation, under the effect of the centrifugal force. An electromagnetic field is created causing the ionised substance to move towards the periphery or centre of the circle under the electromagnetic effect. By creating an equilibrium between these two forces on the substances such that at a given point both substances have an equal chance of being at that point, and because the ions will seek to space themselves equidistantly from one another, thereby requiring the non-ionised atoms to occupy the interstitial spaces, it is possible to produce a better lattice arrangement of the atoms of said substances.

Description

2340507 ELECTROMAGNETIC CENTRIFUGAL ALLOYING This invention relates to the

alloying or combining of materials to produce new alloys or combinations thereof, in particular for use in the electronics, photonics and nanotechnology industries.

Various naturally occurring elements and compounds, or elements and compounds extracted therefrom, have been combined by human beings for many centuries for the purposes of creating stronger materials or materials with other desirable properties. For example early man learned to combine copper and tin, both of which are soft metals in themselves, to produce bronze, an alloy which is stronger than either. Such alloys derive their strength from the lattice arrangement of different sized atoms which prevents the atoms from sliding past each other when the material is subjected to tensile, compresile or other forces. A common method of such alloying is to heat the materials to a temperature at or above the melting points of both and to combine them in liquid form, allowing them to cool to solid form thereafter.

More recently, human beings have combined different substances such as gallium and arsenic to produce materials with such properties as better electrical conductivity, greater resistance to heat distortion caused by electrical current load or better transmission of photons. These materials have many useful applications in electrical, electronic, photonic and photo-electrical devices. Such products include logic circuits, microprocessors, memory chips, light emitting diodes, optical fibres and materials for converting solar radiation to electricity. Various sophisticated methods for combining such materials have been developed, including vapour-phase deposition wherein one of the substances is deposited in vapour form on the solid surface of the other substance.

A further proposed use for combined substance materials is in the production of socalled nano-structures, small scale structures which perform mechanical or electrical operations like mechanical machines but on a much smaller scale. Proposed uses include internal medical diagnosis and radio relay, medical treatment such as eating up blood clots and attacking cancer cells, eating up industrial waste or spillage or converting such waste or spillage to a harmless form and nano-scale assembly of other industrial products.

A problem with previously existing methods of alloying and combining materials is that it is hard to produce a perfect three dimensional lattice arrangement wherein the atoms of the different substances are laid out in a perfect alternating pattern in three dimensions, or wherein the pattern is precisely symmetrical and homogenous throughout the mixture or a significant portion thereof A related problem is the problem of lattice mismatching, wherein there are differences of spacing between the atoms of the different substances. Even tiny mismatches can give rise to strains that result in material flaws. Moreover, for some mixtures, the mismatch factor can'be quite high.

In the case of alloys or combinations produced for their physical strength, these mismatches and imperfections can have the effect of physically weakening the material, causing it to become brittle or to possess less tensile or compresile strength than would be the case if the lattice mismatches were absent and the alignment and combination of I substances in the alloy or mixture were perfect. In the case of alloys or combinations of substances produced for the purpose of conducting electricity, storing electrical charges, conducting photons, or photoelectric operations, said imperfections can greatly reduce the efficiency of such materials. Moreover, in the case of logic circuits, microprocessors and memory chips, and information storage devices, such defects can necessitate the use of wider lines for the conducting of electricity or light, or of larger areas for the storage of electrical charge. This in turn means that such devices will not be as small or have as much capacity per volume as would be the case if these imperfections of the microstructure were absent.

It is known that different substances have difFerent densities and different specific gravities. It is also known that different substances have different melting points. It is also known that different substances have different ionisation temperatures and ionisation potentials. It is further known that electrically charged bodies tend to move to the area of lowest electrical potential, away from other similarly charged bodies. It is further known that electrical currents flowing in parallel media in the same direction will exert an attractive force on one another, while electrical currents flowing in opposite directions in parallel media will exert a repulsive force on one another. It is further known that a negatively charged particle moving in parallel to such a current flow will be attracted to the medium carrying the current, if the current is flowing in the same direction as the negatively charged particle is moving, or repelled from the medium carrying the current, if the current is flowing in the opposite direction.

1 However, these known phenomena and properties have never previously been used in conjunction or combination with one another in the method of alloying or combining of materials described herein to overcome lattice mismatches or structural imperfections.

According to the present invention there is provided a chamber into which are placed C the at least two substances to be combined. Said substances are either placed in the chamber in molten form or are heated to become molten within said chamber, at least one but not all of said substances being either placed in the chamber already ionised or alternatively heated in the chamber to the temperature at which said at least one substance becomes ionised. The chamber is rotated at high speed such as to cause the denser substance to accumulate further from the axis of rotation than the less dess substance, under the effect of the centrifugal force. An electric current is passed through one or more electromagnetic coils or rings which are positioned in relation to the chamber such as to create a magnetic field when said current is passed through said coils or rings. Depending on the configuration of the coils or rings and on the choice of substances, said electromagnetic field will cause the ionised substance or substances to move towards either the periphery or the axis of rotation. By controlling the speed of rotation and the strength of the magnetic field according to known equations of physics, it is possible to create an equilibrium between the effect of the electromagnetic and centrifugal forces on the atoms or molecules of the at least two substances in the chamber such that atoms or molecules of the ionised and the non-ionised substance will have a co-equal probability of being at a particular distance from the axis of rotation. Because electrically charged bodies always tend to move to the area of lowest electrical potential, electrostatic repulsion between the ions will cause said ions to move to such positions as provides the maximum amount of spacing between each other. Therefore, while the ionised atoms will have a co- equal probability with the

2 non-ionised atoms of occupying the spaces at a given distance from the axis of rotation, electrostatic forces will prevent any two of said ions from occupying adjacent positions at such a distance and consequently these interstitial positions win be occupied by one or more of the nonionised atoms. Thus a perfect lattice arrangement will be formed by the equilibrium of these forces.

Furthermore, because the electrostatic forces will cause the ions to move to such positions as to be equidistant from one another, this effect of forming a perfect lattice will be propagated into the third dimension. That is, while some of the ions will accumulate at either the axis of rotation of the chamber or the furthest point from it (depending on the configuration and choice of substances), once these places are occupied, other ions will settle into progressively further positions from the axis or periphery in order to space themselves equidistantly from each other. The non-ionised atoms of the other substance will be caused by their physical exclusion from these occupied spaces to fit into the spaces thus vacated. This will create a high degree of probability of a perfect lattice arrangement throughout the combined substance.

A preferred embodiments is now described with reference to the accompanying drawings.

In one embodiment, illustrated in cutaway form in Figure 1, suitable for instances wherein the heavier of the substances to be combined has a lower ionisation potential than the lighter substance, a chamber (1) is cylindrical and is surrounded on the outside by an electromagnetic coil or a series of electromagnetic rings (2) through which an electrical current can be passed. Inside the chamber are placed, respectively, the lighter substance (3) and the heavier substance (4) of lower ionisation potential. In this preferred embodiment, said substances are poured into the chamber in molten form and heated to such an extent that the heavier substance is ionised. The chamber (1) is rotated rapidly along its central axis such as to cause the heavier substance (4) to accumulate at the furthest point in the chamber from the axis of rotation under the centrifugal force. This rapid rotation of ions will cause a virtual current to flow through the ionised substance. Approximately contemporaneously with said rotation, an electrical current is passed through the electromagnetic coils or rings in the opposite direction to the virtual current thereby creating an electromagnetic field which will exert a repulsive force on the heavier substance thereby causing said substance to move towards the central axis of the cylindrical chamber. In the process, the lighter substance (3) will be correspondingly forced to the periphery of the circle or rotation as it is displaced by the heavier substance (4) moving towards the central axis.

By appropriate selection of the speed of rotation of the cylindrical chamber (1), and the strength of the electrical current in the electromagnetic rings (2) or coil, it is possible to balance the electromagnetic and centrifugal forces on the respective atoms such that at the periphery of the circular cross-section of the chamber there will be an equal probability of an atom of the heavier or the lighter substance being there. Because of electrostatic repulsion and the consequent tendency of the ions to maximise the spaces between themselves, this will create a high probability of a perfect lattice arrangement being formed for the reasons stated above.

3 A narrow closable opening at the periphery, such as a slit (5), is created to drain off this perfectly arranged mixture or alloy by centrifugal forces, thereby allowing more of the substances to fill the space in the periphery of the cylinder thus vacated. As the probability of a perfect lattice arrangement is most likely at the periphery, this method of extraction will extract the portion of the combined substance most likely to have a perfect lattice arrangement.

It is possible to operate the system in a continuous manner by pouring in more of the molten substances at one end of the cylinder while extracting them at the other, or by placing the cylinder such that its rotational axis is vertical and pouring in the substances to be combined at the top end while extracting them through a slit along the periphery as described above. An alternative method of extraction is to let the combined substance cool to the temperature at which it solidifies and then to extract it as a solid block.

In an alternative embodiment, suitable for instances wherein the lighter of the substances to be combined has a lower ionisation potential than the heavier substance, the chamber is of a doughnut shape and the at least one electromagnetic coil or ring is or are placed on the inside hollow of the donut-shaped chamber. The substances are placed in the chamber in molten form such that the lighter substance is ionised (or alternatively is heated to its ionisation point inside the chamber). The chamber is again rotated such as to induce a virtual current flowing through the ionised substance. An electrical current is passed through the at least one electromagnetic coil or ring in the opposite direction to the virtual current such as to cause repulsion between said at least one coil or ring and said positively ionised atoms. The effect of said process is to cause said ionised atoms to move to the furthest point from the axis of rotation of the chamber.

This same doughnut-shaped embodiment could also be used in instances wherein the heavier of the substances to be combined has a lower ionisation temperature. In such instances, the current is passed through the at least one electromagnetic coil or ring in the same direction as the virtual current such as to cause electromagnetic attraction between said positively ionised heavier substance and said at least one electromagnetic coil or ring, thereby causing the heavier atoms to move towards the inner boundary of the circular cross-section of the chamber.

Likewise, for instances wherein the lighter substance has a lower ionisation temperature, in the cylindrical chamber described above, the electrical current through the at least one electromagnetic coils or rings can be passed in the same direction as the virtual current thereby attracting the ionised substance to the periphery of the circle of rotation.

In an implementation of the method suitable for instances wherein more than two substances are to be combined, using one or another of the above embodiments of the apparatus described above, the two substances with the highest melting point are combined first and the system is then cooled, after which the substance with the next highest melting point is added, the process being repeated as many times as necessary to combine all the intended substances in the mixture.

4 In an alternative implementation of the method suitable for instances wherein more than two substances are to be combined, using one or another of the above embodiments of the apparatus described above, the two substances with the highest ionisation temperatures are combined first and the temperature is then reduced, after which the substance with the next highest ionisation temperature is added, the process being repeated as many times as necessary to combine all the intended substances in the mixture.

In an alternative implementation of the method suitable for instances wherein more than two substances are to be combined, using one or another of the above embodiments of the apparatus described above, the two substances with the highest ionisation potentials are combined first and the current to the electromagnetic coils or rings is then reduced, after which the substance with the next highest ionisation potnetial is added, the process being repeated as many times as necessary to combine all the intended substances in the mixture.

In another implementation of the method suitable for instances wherein more than two substances are to be combined, using one or another of the above embodiments of the apparatus described above, the two substances with the highest densities are combined first and the speed of rotation of the chamber is then reduced, after which the substance with the next highest density is added, the process being repeated as many times as necessary to combine all the intended substances in the mixture.

In yet another implementation of the method suitable for instances wherein more than two substances are to be combined, several of the methods above may be used consecutively or simultaneously to optimise results according to the densities, ionisation temperatures and melting points of the substances to be combined.

Claims

Apparatus for combining or alloying at least two materials comprising:

a chamber capable of containing at least two substances in molten form to be combined, said chamber being capable of being rotated fast such as to cause the denser or densest of the said at least two substances to accumulate at the periphery furthest from the axis of said chamber's circle of rotation, under the effect of the centrifugal force; at least one electromagnetic ring or coil positioned in relation to said chamber such as to be capable of creating an electromagnetic field in said chamber such as to either repel or attract an ionised substance either towards the periphery of the circle of said chamber's rotation or the centre of said chamber's circle of rotation.
2. Apparatus as claimed in Claim 1 wherein the chamber is cylindrical and is surrounded on the outside by at least one electromagnetic coil or electromagnetic ring through which an electrical current can be passed, said chamber being capable of being rotated rapidly along its central axis such as to cause the heavier or heaviest substance to accumulate closer to the periphery of the circle under the centrifugal force, said at least one electromagnetic coil or ring being capable of having a current passed through it thereby creating an electromagnetic field inside said chamber.
3. Apparatus as claimed in Claim 1 wherein the chamber is of a doughnut shape and the electromagnetic coils or rings are placed on the inside hollow of the chamber.
4. Apparatus as claimed in any preceding Claim wherein there is an openable and closable opening such as to allow the mixture or alloy to be extracted while the apparatus is in operation.
5. Apparatus as claimed in Claim 4 wherein the opening is a slit.
6. Apparatus as claimed in Claims 4 or 5 wherein the chamber is positioned such that its rotational axis is vertical and wherein the substances are poured in at the top.
7. Apparatus as claimed in Claim 6 wherein the mixture or alloy is drained or extracted from a slit towards the bottom of the apparatus.
8. A method of combining at least two substances utilising apparatus as claimed in any preceding Claim comprising the steps of (a) placing said substances in the chamber either in molten form or heating them within said chamber to become molten; (b) placing at least one substance in the chamber in ionised form or heating said at least one substance in said chamber to its ionisation point; (b) rotating said chamber such as to cause the denser substance to accumulate at the periphery furthest from the axis of rotation, under the effect of the centrifugal force; 6 (c) creating an electromagnetic field such as to cause the either the lighter substance to move to the periphery of the circle of rotation or the heavier substance to move towards the inside of the circle or rotation; (d) adjusting or controlling the speed of rotation of the chamber and/or adjusting or controlling the strength of the current flowing through the at least one electromagnetic coil or ring such as to create an equilibrium between the centrifugal and electromagnetic forces on the atoms or molecules of the at least two substances in the chamber such that at a given point atoms or molecules of both substances have an equal chance of being at a given distance from the axis of rotation.
9. A method of combining more than two substances as claimed in Claim 8 wherein the two substances with the highest melting points are combined utilising the method as claimed in Claim 8 and the system is then cooled, after which the substance with the next highest melting point is added, the process being repeated as many times as necessary to combine all the intended substances in the mixture.
10. A method of combining more than two substances as claimed in Claim 8 wherein the two substances with the highest ionisation temperatures are combined utilising the method as claimed in Claim 8 and the system is then cooled, after which the substance with the next highest ionisation temperature is added, the process being repeated as many times as necessary to combine all the intended substances in the mixture.
11. A method of combining more than two substances as claimed in Claim 8 wherein the two substances with the highest ionisation potentials are combined utilising the method as claimed in Claim 8 and the current in the at least one electromagnetic coil or ring is then reduced, after which the substance with the next highest ionisation potential is added, the process being repeated as many times as necessary to combine all the intended substances in the mixture.
12. A method of combining more than two substances as claimed in Claim 8 wherein the two substances with the highest densities are combined utilising the method as claimed in Claim 8 and the speed of rotation of the chamber is then reduced, after which the substance with the next highest density is added, the process being repeated as many times as necessary to combine all the intended substances in the mixture.
13. A method of combining more than two substances as claimed in Claim 8 wherein more than two substances are combined utilising a combination of two or more methods as described in Claims 10, 11 and 12, said combination being performed either consecutively or simultaneously.

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