FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
PATENTS RULES, 2006
COMPLETE SPECIFICATION (SECTION 10; RULE 13)
"A HARD GOLD ALLOY AND ITS COMPOSITION THEREOF"
SUBODH PETHE, AN INDIAN NATIONAL, HAVING MY RESIDENCE AT 402.A-6, VIKAS COMPLEX, CASTLE MILL.THANE 400601, MAHARASHTRA, INDIA.
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

TITLE:
A hard gold alloy and its composition thereof.
FIELD OF THE INVENTION:
The present invention relates to a hard gold alloy specifically a gold_titaniun\and boron alloyof higher caratage and its composition.
BACKGROUND OF THE INVENTION:
Precious metals like gold and silver in its pure form are too soft for practical use. They are so soft, malleable and ductile in their elemental form that it is necessary to improve the characteristics of the metals by increasing their elasticity and obtain greater rigidity and wear resistance by rendering them hardenable. This is one important reason why precious metals need to be alloyed.
The alloying agents impart to these precious metals their properties so that the resultant alloy is worked into shape by hand fabricating, casting, pressing, spinning, etc. during jewelry making.
Depending on the application of the alloy and requirement of special qualities like degree of ductility and hardness, colour, etc., each alloy may require different

percentage or formula of alloying agent. For jewelry making, ideally the alloy should be such that itbe able to be worked using normal jewelry fabrication techniques and polish easily and present a lustrous surface and should be easy to recycle or refine.
A 24-carat gold is pure gold (99.99 wt% of gold) and too soft for jewelry making and therefore traditionally it has been alloyed with a metal like copper, silver or zinc; however this would results in reduced purity and hence the caratage.
There exists a demand for jewellery of very high-caratage with acceptable durability.lntenseresearch has been carried out to develop an alloy of higher carat gold capable of being wearable as jewellery. The resultant alloy should be such that it can be hand wrought, cast, refined and be worked by traditional working methods.
The development of an optimum alloy can be a lengthy and time consuming task. In formulating a new alloy it is important to keep in mind the needs and the skills of the bench trained jeweler as the majority of craftsman jewellers in the world are small workshop operators. One also has to check from a broad selection of elements/earth metals, from which to draw and achieve the desired properties of the alloy.
There are numerous patent and non-patent literatures that illustrate specification of gold alloys of 24 carat purity with various metals and earths:

In 1974 International Gold Corporation Ltd (Intergold) in association with Engelhard Industries studied composites of gold with up to 1 per cent of various oxides. The composites were made by conventional powder metallurgy techniques, and the expected strengthening of the metal was observed both at norma! and at higher temperatures, but the products were not regarded as sufficiently attractive for general use in the fabrication of jewellery. (Gafner, 1989)
In 1980, gold was alloyed with small amounts of reactive metals, such as zirconium, and attempts were made at in situ reaction with gases such as oxygen and nitrogen at high temperature and pressure. Owing to extremely low permeability of gold, little reaction (and thus hardening) occurred at meaningful depths, and the approach was dropped. In the second study, powder-metallurgy methods were used to combine gold and selected glass powders to give a new range of gold-glass composites. These proved well-suited to stamping but involved too high a level ofjechnology for the usual goldsmith. There were also_doubts about purchaser acceptance of this strange combination^ materials. (Gafner, 1989)
In 1993, gold alloys of 99% purity containing 200-2000ppm of one or more elements- calcium, beryllium, germanium and boron and further addition of 10-1000ppm of one or more metals including magnesium, aluminium and cobalt and/or 10-1000ppm of rare earth metals and yttrium were known. Their hardness value was in the range of Hv100-140 which is not very considerable (Mitubishi Material Corporation, Japan)

In 1995 a patent was granted for an age hardenable alloy of 99.7wt% gold containing 50ppm of gadolinium and optional third metal calcium, aluminium or silicon (100-3000ppm) had hardness comparable to an 18carat i.eHv 176 (Pure Gold- 30 company, Japan)
Several patents have been granted for improved strength gold bonding wires (for electronics applications) that cite additions of bismuth, rare earths, calcium with beryllium, europium and niobium, germanium, barium, yttrium and rare earths, or calcium and lead.
The age hardenable alloy of 995 fineness (99.5wt%) purity containing 0.2wt% cobalt and 0.3wt% antimony had achieved hardness of Hv 100 in cold-worked condition and Hv142 in cold worked and aged condition. (Mtntek, South Africa)
The problem associated with the above micro-afloyed gold is that the alloy may gain considerable strength by usingcalcium and /or other earths elements, but there is loss of strength on remelting and such alloys cannot not be simply remelted and recycled.
The micro-alloying of gold is also applicable to 22 carat (91.6wt%) to 24 carat (99.9wt%) golds and the number of possible alloying metals that have been known are cobalt, antimony, germanium, zirconium and vanadium. Nickel and cobalt when alloyed with gold showed effective hardness but nickel was undesirable due to skin allergy

effects and 22 carat gold with 2% cobalt is known to lower the alloy density and also its ductility.
US patent US2003034097 describes making of a hard precious metal alloy having gold Au content from 37.50 to 98.45 wt%, and a hardening additive in a range of 50 ppm- 15,000 ppm, wherein the hardening additive is constituted of gadolinium Gd only, or gadolinium Gd and at least one element selected from the group consisting of rare-earth elements other than Gd, alkaline-earth elements, silicon Si, aluminum Al, and boron B.
The development of gold-titaniumium alloy, wherein 24 carat gold alioy(990 fineness) with 1% titanium giving a colour close to that of pure gold, and a durability (resistance to wear and impact) as good as that of standard jewellery alloys is known in the art.But the production of 990 alloy requires sophisticated vacuum melting and complex procedure and refining of gold is difficult. (Gafner, 1989)
A range of 8 to 22 carat of gold-silver-copper and/or zinc alloys containing 0.1 -1.0wt% of titanium is also known in the art, (Silmer Spa, Italy).
According to a published literature, 24 carat goldcan be hardened by small alloying additions (0.5% or less by weight) of rare earth metals like gadolium, and calcium, others include boron, silicon, aluminium and yttrium.

Due to the presence of Ruthenium in the compositions, refining was difficult. In India, parting is the preferred method for refining gold.Using the parting method, Ruthenium doesn't get eliminated and keeps accumulating in gold over a period of time.
In view of the above stated problems, a need was felt in the art for a hard gold alloy-having increased hardening value (like that of lower caratage gold) and maintaining the ductility, colour, tensile strength and other properties of gold essential in jewellery making and still be easy for refining. Preferably, the gold content in the said alloy was more than 22K.
OBJECT OF INVENTION:
It is an object of the invention to overcome or ameliorate atleast one of the disadvantages of the prior art, or to provide a useful alternative.
It is an object of the invention in its preferred form to provide a gold alloy of higher caratage (more than 22 carat), having increased hardness without impairment of the ductility, colourjnelting, and refining properties of gold.
Yet another object of this invention is to provide a gold alloy of higher caratage having hardness value of that of lower caratage gold alloy with increased wear resistant properties.

Further object of the present invention is to provide 'springiness' in the gold alloy, which is primarily due to Boron at a weight percentage of 0.01 to 0.10, preferably 0.9%.
It is an object of the present invention to provide an alloy which is easily refined by parting method (which is the normal method for refining in India).
It is also another object of the present invention to give better polish to gold having more than 22 carat, which is normally not possible.
Still another object of the invention is to provide a gold alloy that is stable, regarded as sufficiently attractive for general use in the fabrication of jewellery, resistant to wear and tear and not undesirable to skin.
SUMMARY OF THE INVENTION:
Accordingly, a hard gold alloy member of higher carat gold with an increased hardness is provided herein. The increased hardness is due to selection of such hardening/alloying agents.

The invention comprises of the hard gold alloy which includes gold of more than 22 carat, 0 to 7.3wt%copper,0 to 7.3wt%silver, 1 %wt titanium and 0.01 to 0.10 wt% boron.
DETAILED DESCRIPTION:
The present invention will be described in detail hereinafter.
A hard gold alloy of the present invention is constituted of gold more than 22 carat, 0 to 7.3wt%copper,0 to 7.3wt%silver, 1 %wt titanium and 0.01 to 0.10 wt% boron. According to the present invention the present invention includes gold in the percentage of more than 91.6 wt%.
To effectively harden gold, it is essential that the alloying metal must dissolve readily in molten gold and stay in the gold stay in solution down to about 800°C (which is an ideal solutionizing temperature) to allow the alloy to be produced in a ductile form by quenching from that temperature. Between that temperature and about 400°C, the additive should segregate to form a hardening phase of as large a volume as possible. It was noted that titanium has by far the highest hardening factor i.e 12.5 NHA and hence the selection of titanium for developing the alloy.

According to a preferred embodiment the present invention comprises of gold having more than 22 carat (more than 91.6Wt% gold), 0 to7.3 wt% copper.O to 7.3wt% silver, 1 %wt titanium and 0.01 to 0.10 wt% boron.
According to another embodiment, the alloy comprises of comprising of gold in the range of 91.7 wt% to 97 wt% gold, 0 to 7.3 wt% copper, 0 to 7.3 wt% silver, 1 %wt titanium and 0.01 to 0.10 wt% boron.
In a preferred embodiment, boron is 0.9 wt%. In a preferred embodiment, the percentage of gold is upto 24 carat (98.9 wt%)-
Working Example:
The following table summarizes the compositions present in the present invention:
Table

% age weight % age weight % age weight % age weight % age weight
Gold 91.7 92 95.8 96 98.9
Copper 0-7.29 0 - 6.99 0-3.19 0 - 2.99 0.09
Silver 0-7.29 0 - 6.99 0-3.19 0 - 2.99 0.09
Titanium 1 1 1 1 1
Boron 0.01-0.10 0.01 -0.10 0.01-0.10 0.01-0.10 0.01-0.10

Advantages of the present invention:
• Ease of manufacturing of jewellery because of increased hardness;
• User saves on gold;
• The hard gold alloy jewellery has reduced scratches;
• There is less bending of the gold;
• Increases tensile strength;
• Better manual workability;
• The gold has more luster;
• It is environmentally friendly; and
• Ease of refining by parting method.

I claim:
1. A hard gold alloy comprising of 91.7 to 98.9 wt% gold, 0 to 7.29 wt% copper, 0 to 7.29 wt% silver, 1 %wt titanium and 0.01 to 0.10 wt% boron.
2. A hard gold alloyas claimed in Claim 1, comprising of 95.8 to 98.9 wt% gold, 0 to 3.19 wt% copper, 0 to 3.19 wt% silver, 1 %wt titanium and 0.01 to 0.10 wt% boron.
3. A hard gold alloy as claimed in Claim 1, comprising of 91.7wt% gold, 0 to 7.29 wt% copper.O to 7.29 wt% silver, 1 %wt titanium and 0.01 to 0.10 wt% boron.
4. A hard gold alloy as claimed in any of the Claims 1 to 3, wherein boron is 0.9 wt%.