Special purpose glass with Zirconium

Posted on : 04-02-2021    Author : Maya Sidharth Nagan

Zirconium is used in some of the newest technologies in many industries including nuclear reactor and in satellites as a reflective surface agent because of their superior mechanical, thermal, electrical, chemical and optical properties. Here we look further about its optical properties and application in glass industry.

Zirconium is found in two minerals, zircon (zirconium silicate, ZrSiO4) and baddeleyite (zirconium oxide, ZrO2). The most important of these ores, zircon, occurs as grains concentrated in sand deposits in the USA, Australia and Brazil. In India, there are vast deposits of zircon in the coastal beach sands of Kerala, Tamil Nadu and Orissa where it occurs to the extent of 5-9 per cent. 

Zirconium chemicals are applied to increase the refractive index in optical glasses and for glass toughening. Zirconia and zirconium hydroxide are added for these purposes. Finely divided zirconium oxide is also used for polishing glass. Zircon is also used in the production of alkali resistant glass, It is also used in LCD and Plasma display panels, such glass panels contain up to 1% of zirconium oxide. Materials including zirconium oxide are also applied as very thin layer in glass surface such as mirrors and lens for abrasion resistance

Another application of zirconia in optical industry is a crystal ball known as Cubic Zirconia ball with refractive index of 2.17. High refractive index of Cubic Zirconia material makes it reliable material used as a Ball lens for optical telecom products; especially in fiber optic cabling (OFC). They are used in fiber coupling, for the reflection of signals or transmission between multiple OFC i.e connectors and check valves. The lens is available in different size but usually less than 1mm also used in laser focus lens device, microscopy and ideally suited as a collector in LED lighting. In addition to the optical properties of Cubic Zirconia, it is also wear resistant and can withstand severe chemical corrosion. Cubic zirconia is used in the production of artificial diamonds commonly used in ornaments.

A metal alloy having Zirconium (Zr55) called ‘Bulk metallic glasses’ (BMGs) or simply 'Metallic glass'   (amorphous metals) shouldn’t be mistaken as any type of glass, it is a solid metallic material.  Amorphous metals are non-crystalline, and have a glass-like structure. But unlike common glass which is an insulator, amorphous metals have good electrical conductivity and they also display superconductivity at low temperatures.