IP Black Gold
IP Black gold is a type of gold used in jewelry. It is a very fashionable and high value material used by many top designers as Lagerfeld, Boss, Lambretta. It is mainly used for Men Jewelry due to its shinning and durability.
IP does not mean "iron plated", it means ion plated. This is a vapor process where the gold is vaporized and the metal, usually stainless steel, is then coated with the vapor. And it is definitely not " fully gold ".
- Electroplating, using black rhodium or ruthenium. Solutions that contain ruthenium give a slightly harder black coating than those that contain rhodium.
- Patination by applying sulfur- and oxygen-containing compounds.
- Plasma-assisted chemical vapor deposition process involving amorphous carbon
- Controlled oxidation of gold containing chromium or cobalt (e.g. 75% gold, 25% cobalt
Cobalt-containing alloys, e.g. 75% gold with 25% cobalt, form a black oxide layer with heat treatment at 700–950 °C. Copper, iron and titanium can be also used for such effect. Gold-cobalt-chromium alloy (75% gold, 15% cobalt, 10% chromium) yields a surface oxide that's olive-tinted because of the chromium oxide content, is about five times thinner than Au-Co and has significantly better wear resistance. The gold-cobalt alloy consists of gold-rich (about 94% Au) and cobalt-rich (about 90% Co) phases; the cobalt-rich phase grains are capable of oxide-layer formation on their surface.
More recently, black gold can be formed by creating nanostructures on the surface. A femtosecond laser pulse deforms the surface of the metal, creating an immensely increased surface area which absorbs virtually all the light that falls on it, thus rendering it deep black.