Industrial applications of sapphire

2022/05/28 16:18

Although sapphire is high-satisfactory called a valuable stone utilized in jewelry, it additionally has many commercial makes use of way to its first rate mechanical, optical, thermal, electrical, and chemical properties. Methods to artificially manufacture sapphire had been advanced over a hundred years ago, and as cutting-edge advances have allowed better great sapphire to be produced extra consistently, the economic programs retain to increase.

Methods of creating sapphire

Sapphire is a crystal made of aluminum oxide (Al2O3). The mineral name is corundum. Pure corundum is colorless and transparent but tiny amounts of impurities can give it a red, blue, yellow, or pink hue. Corundum that is dark red is known as a ruby, while other colors are often called sapphire. Artificially created corundum of any color except red (including colorless and transparent) is known as sapphire.

A method to synthesize sapphire was developed by the French chemist, Auguste Verneuil, in 1881 and publicized in 1902. In the Verneuil method, aluminum oxide power is heated to 2000 deg C in a furnace to create mist-like droplets of Al2O3. The furnace is then cooled slowly to allow the Al2O3 to accumulate on a seed sapphire particle inside the furnace. In Verneuil’s time, it took about 3 hours to produce 10 – 15 carats of sapphire crystal using this method.

Following this, sapphire’s excellent properties gained attention for industrial use. As demand for synthetic sapphire increased, new manufacturing methods, such as the Czochralski, Kyropoulos, crucible, and EFG methods, were developed. In the EFG method, any crystal orientation can be selected. This means c-plane, r-plane, a-plane, or m-plane crystals can be produced as needed. This method has a fast growth rate and produces highly homogeneous crystals.