We are all accustomed to the fact that gold should always be golden. And even when they talk about white gold or rose gold, it is still is something unusual and strange. It seems that a huge rarity rose gold, and black and gold does not exist. But it turns out, may well, and there is. That's only created black gold, just like everything else color gold, artificial means of chemical reactions.
Remember that pure gold is always yellow. Other gold colors are obtained by alloying gold with other elements in different proportions.
Here is a simple example. When taking 14 parts pure gold and 10 parts alloy, produced a 14- karat gold. At the same time, if we take 18 pieces of gold and 6 parts of alloy will 18K gold and so on. But when it comes to the sample number 585 or 750 considering the ratio 14/24 and 18/ 24.
What added to the gold to get other colors? If silver is added to give a white gold, and the addition of copper gold to red. A mixture of a copper and silver in the proportion of 50 to 50 has the same yellow alloy, but at trial - the use of this alloy is very common in the market of jewelry. If a bit added to a zinc alloy, it would be more durable.
The most common sample of gold is pure gold 24K or 22K (92 percent gold), then 18K (75 percent gold), 14K (58 percent gold), 10K (41 percent gold) and 9K (only 38 per cent of gold).
Color gold is separated into three groups:
1. Au-Ag-Cu system, producing white gold, yellow gold, green gold, red gold with alloy.
2. Gold blue and purple gold and other colors make using intermetallic compounds. But it brittle metals as intermetallic compounds have a crystalline structure that differs from the structures of the parent metal. This gold is used in jewelry for jewelry gemstones.
3. Black gold is created in several ways, pi using a surface oxide layer, and its properties depend on the volume of the alloy. The surface of the black gold is peculiar to wear.
Often under the black gold understand nothing like oil. But we're going to talk specifically about the black gold. Black gold is a type of gold used in jewelry. This question is about black gold, or blackened by chemical reactions and compounds of different metals.
There are three methods you can use to get the black gold:
1. Electroplating, there is used a black rhodium or ruthenium. When using ruthenium black gold (blackened coating) is obtained heavier than the black gold rhodium-based.
2. Patination gold compounds using oxygen and sulfur.
3. Plasma compound by vapor deposition, a complex process involving amorphous carbon.
4. Oxidation using chromium- gold and cobalt (e.g., 75 percent gold and 25 percent cobalt).
It is also possible to obtain not only black gold, but its various shades of brown, with copper compounds, and potassium sulfide treatment.
Cobalt -containing alloys pose a black oxide layer by heat treatment between 700 and 950 degrees Celsius. Iron, titanium, and copper can also be used to similar effect. An alloy of gold, chromium and cobalt (75-15-10 percent) gives the surface because of the olive hue of chrome.
More recently developed a laser technique that makes the surface of metals deep black color. All is due to the formation of nano-structures. The surface is created, capable of absorbing virtually all the light; it also makes it a deep black color.
As you can see, the black gold is obtained very complex ways. Not every jeweler is able to create a solid surface of the black gold.
White gold is an alloy of gold with at least one white metal. Most often it is nickel, palladium and manganese. Just like pure gold, white gold is a sample.
Properties white gold varies depending on which metal was used to create it, and in what proportions. White gold alloys can be used for completely different purposes. For example, an alloy of nickel and gold, solid and strong, it is well suited for the manufacture of rings and pins. Slept gold and palladium is soft and suitable for framing gems. Gold in an alloy with other metals silver, platinum, copper, even more robust, but the jewelers to work with him more difficult.
It is important to understand that white gold can be very different shades. White gold is just a name, in facts, its color can vary from pale yellow to light brown, and even pale pink shades. In the jewelry business at times like "dirty" alloys coated with rhodium, and get a «pure white» color.
Copper is added to the white gold to increase its flexibility.
Alloys, which are often used in jewelry is gold - palladium - silver or gold -nickel- zinc brass. Copper and nickel - are the main components in creating bleaching white gold and zinc secondary component, in order to weaken the color of copper.
The green gold alloy with a gold and silver. In fact, these alloys look like a greenish -yellow, and not purely green. Green gold is 18K gold, containing a mixture of 75 percent gold, 25 percent silver (or 73-27).
Green gold were produced as early as 860 BC, and then called him Electra - a natural alloy of gold and silver.
Also for manufacturing green gold cadmium can be used, about 4 percent for truly green. An alloy of 75 percent gold, 23 percent copper, 2 percent cadmium gives bright green color. 75 percent of gold, silver, 15, 6 and 4, cadmium copper give a dark green color of the alloy. But it is worth remembering that cadmium is toxic.
Purple gold and blue gold
Purple gold is called amethyst gold, an alloy of gold and aluminum intermetallic. Purple gold is more brittle than all other alloys, because here there are intermetallic compounds, and not malleable alloy. A sharp blow can destroy a purple gold. Therefore, most often purple gold is used for jewelry with precious stones, together with pure gold.
Yes, there are still gray and gold, it is made with silver, copper, and manganese in certain proportions.
The alloy of indium and gold as a percentage of 54-46 gives the blue gold. Here, too, it turns intermetallic compound, and appears as a grayish color. Connect with gallium gives a slight blue tint.
Intermetallic compounds corrode less noble metals leach into the environment, forming a layer on the gold surface. Keep close gold blue and purple flowers are impossible, as can happen leaching of metals and their surface changes color.
Red gold and rose gold
Jewelry making is often used rose gold, is nothing more than the alloys of gold and copper. These alloys can be given as pink gold and red gold. In the early nineteenth century, like the gold was very popular in Russia, and it is often called Russian gold, however, a long time ago.
The difference between the pink gold and red gold lies in the different copper content. The more copper gold, the more it is red.
Standard alloy rose gold is 75 percent gold and 25 percent of the mass (18K gold). Standard red gold alloy is 50 percent gold and 50 percent copper.
Also, the alloy may be used 15 percent zinc, changing color to reddish yellow or dark yellow.
In ancient times, in the process of melting the gold of ignorance is often added impurities, which provides the red color. Therefore, many Greco -Roman texts and medieval texts describe as red gold.
Interestingly, the end of the flute is often made of pink gold.