GB1588418A

GB1588418A - Artefacts incorporating industrial diamonds

Info

Publication number: GB1588418A
Application number: GB1253677A
Authority: GB
Original assignee: UK Atomic Energy Authority
Current assignee: UK Atomic Energy Authority
Priority date: 1978-05-17
Filing date: 1978-05-17
Publication date: 1981-04-23

Description

(54) IMPROVEMENTS IN OR RELATING TO ARTEFACTS INCORPORATING INDUSTRIAL DIAMONDS (71) We, UNITED KINGDOM ATOMIC ENERGY AUTHORITY, London, a British Authority, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to industrial diamonds, that is to say, diamonds which are used for industrial purposes instead of as gemstones.

Diamonds, cutting as is well known, are used industrially in cutting and drilling tools, and also for record play-back styli. It appears that in use under dry conditions such diamonds wear by the removal of amorphous material by a process akin to monolayer peeling. Under wet conditions, the process of wear is less well defined, but it is still considered to occur on an atomic scale.

According to the invention there is provided a process for improving the wear characteristics of industrial diamonds, comprising the operation of implanting into the surface regions of the diamonds, ions of a material having an atomic weight greater than one and such as to affect the surface properties thereof.

The surfaces can be effected in a number of ways, for example the diamond lattice may be damaged causing a localised surface region of enhanced hardness. The implantation of carbon ions can achieve this. Alternatively, the ions can be such as to have an affinity for a lubricant used in conjunction with the cutting or grinding tool of which the diamonds form a part. Nitrogen ions are believed to enhance the adsorption of water and so act in this way when the diamond tool is used in a wet cutting operation.

As an example of the invention, a conical diamond stylus having an apex angle of 60 was implanted with three equal doses of N+ ions at energies of 100, 200 and 300 keV to a total dose of 9 x 1015 ionall (Cm2). The stylus was then mounted in a holder and brought into contact with a mirror finished titanium carbide disc rotating at a rate of 100 revolutions per minute. Clean water was allowed to flow over the disc to act as a lubricant. A load of 15 gms was applied to the stylus and the time to failure of the stylus measured. The experiment was then repeated with other styli which had been implanted with the same ion dose, but which were subject to differing loads. Finall the experiment was repeated with unimplanted styli which also were subject to differing loads.The results are summarised in the drawing accompanying the provisional specification in which the solid circles represent results obtained with implanted styli, the open circles represent results obtained with unimplanted styli, and the arrows indicate that no failure of the relevant stylus occured. It can be seen that the performances of the implanted styli are consistently better than those of the unimplanted stylus.

As another example of the invention, diamonds which had been subjected to the same treatment as that used in the previous example, were incorporated into tools which were then used in high speed dry flycutting operations as part of the process of producing poly methyl methacrylate artefacts. Under industrial conditions, the implanted diamond cutting tools were found to have a working life at least five times that of conventional diamond cutting tools when used for performing the same operations. Furthermore, the deteriortion of the tool was regular, rather than catastrophic as is usual with diamond cutting tools.

As a third example of the invention, diamonds which had been implanted with doses of C+ ions of 3 x 1015 ions/cm2 at each of the energies 100, 200 and 300 keV were used for the same operations as for the second example. The implanted diamond cutting tools were found to have a working life approximately twice that of conventional diamond cutting tools.

WHAT WE CLAIM IS:- 1. A process for improving the wear

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. (54) IMPROVEMENTS IN OR RELATING TO ARTEFACTS INCORPORATING INDUSTRIAL DIAMONDS (71) We, UNITED KINGDOM ATOMIC ENERGY AUTHORITY, London, a British Authority, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to industrial diamonds, that is to say, diamonds which are used for industrial purposes instead of as gemstones. Diamonds, cutting as is well known, are used industrially in cutting and drilling tools, and also for record play-back styli. It appears that in use under dry conditions such diamonds wear by the removal of amorphous material by a process akin to monolayer peeling. Under wet conditions, the process of wear is less well defined, but it is still considered to occur on an atomic scale. According to the invention there is provided a process for improving the wear characteristics of industrial diamonds, comprising the operation of implanting into the surface regions of the diamonds, ions of a material having an atomic weight greater than one and such as to affect the surface properties thereof. The surfaces can be effected in a number of ways, for example the diamond lattice may be damaged causing a localised surface region of enhanced hardness. The implantation of carbon ions can achieve this. Alternatively, the ions can be such as to have an affinity for a lubricant used in conjunction with the cutting or grinding tool of which the diamonds form a part. Nitrogen ions are believed to enhance the adsorption of water and so act in this way when the diamond tool is used in a wet cutting operation. As an example of the invention, a conical diamond stylus having an apex angle of 60 was implanted with three equal doses of N+ ions at energies of 100, 200 and 300 keV to a total dose of 9 x 1015 ionall (Cm2). The stylus was then mounted in a holder and brought into contact with a mirror finished titanium carbide disc rotating at a rate of 100 revolutions per minute. Clean water was allowed to flow over the disc to act as a lubricant. A load of 15 gms was applied to the stylus and the time to failure of the stylus measured. The experiment was then repeated with other styli which had been implanted with the same ion dose, but which were subject to differing loads. Finall the experiment was repeated with unimplanted styli which also were subject to differing loads.The results are summarised in the drawing accompanying the provisional specification in which the solid circles represent results obtained with implanted styli, the open circles represent results obtained with unimplanted styli, and the arrows indicate that no failure of the relevant stylus occured. It can be seen that the performances of the implanted styli are consistently better than those of the unimplanted stylus. As another example of the invention, diamonds which had been subjected to the same treatment as that used in the previous example, were incorporated into tools which were then used in high speed dry flycutting operations as part of the process of producing poly methyl methacrylate artefacts. Under industrial conditions, the implanted diamond cutting tools were found to have a working life at least five times that of conventional diamond cutting tools when used for performing the same operations. Furthermore, the deteriortion of the tool was regular, rather than catastrophic as is usual with diamond cutting tools. As a third example of the invention, diamonds which had been implanted with doses of C+ ions of 3 x 1015 ions/cm2 at each of the energies 100, 200 and 300 keV were used for the same operations as for the second example. The implanted diamond cutting tools were found to have a working life approximately twice that of conventional diamond cutting tools. WHAT WE CLAIM IS:-

1. A process for improving the wear characteristics od industrial diamonds, comprising the operation of implanting into the surface regions of the diamonds, ions of a material having an atomic weight greater than one and such as to affect the surface properties thereof.

2. A process according to claim 1 wherein the ions are ions of carbon or nitrogen.

3. A process according to claim 2 wherein the diamonds are implanted with ion doses of 3 x 1015 ions/cm2 at each of the energies 100, 200 and 300 KeV.

4. A process for improving the wear characteristics of industrial diamonds substantially as hereinbefore described.