Transparent ceramics are crystalline and glassy in nature. These ceramics are used as optically transparent materials in different forms (from bulk solid-state components to high surface area forms such as fibers, coatings, and thin films). Transparent ceramics are included under the optical transparent category of ceramics. The term “ceramics” is used to define both crystalline materials as well as amorphous materials; however, transparent ceramics are noted to possess crystalline structure. These ceramics are derived through a crystallization process from silica based glass. Transparent ceramics offer properties that are different from conventional ceramics.
Currently, optoelectronics and optics is the most important application segment in the transparent ceramics market. In this sector, the key application is for fabricating solid state lasers, where transparent ceramics are commonly used as optical windows for gas lasers, host materials, and for other components such as lenses, amplifiers, and optical insulators. Furthermore, these ceramic materials are utilized for the production of lamp and bulb envelopes for vehicle and commercial lighting products. Transparent ceramics are used in applications where harsh chemical conditions coupled with resistance to high temperatures are required. Additionally, these ceramics can be introduced for developing displays and lights in light-emitting diodes (LEDs). Over the past few years, the market for transparent ceramics has expanded to include materials that are not only transparent to ultraviolet and infrared light, but also to electromagnetic waves in the visible spectrum.
Transparent ceramics are proving to be a promising alternative to traditional glass technologies and single-crystal technologies in various diverse application fields such as high-energy radiation detection, infrared domes, lasers, optical fibers, and armors. In this context, the term “transparent” is defined as a ceramic material with approximately 90% of theoretical transmission over the wavelengths of interest. Transparent polycrystalline ceramics have the ability to provide unique and versatile optical materials that are highly suitable for nonlinear optics, solid-state lasers, and scintillators.Focusing on technology advancement, researchers have recently discovered how to transform amorphous forms of glass oxides into transparent ceramics through complete crystallization, unlike the traditional technologies. Transparent ceramics can also be fabricated to meet the requirements for commercial applications. This would help promote the emergence of new technologies for broad usage in applications ranging from automobile ignition to inertial confinement nuclear fusion.
The light must be transmitted through the material, which needs to be transparent in nature without significant reflection and absorption losses. Unlike many single crystals and glasses, polycrystalline ceramics comprise complex microstructural features such as pores, grain boundaries, grains, and secondary phases or inclusions. Spinel ceramics, a type of transparent ceramic have been present in the industry for a long time, with another transparent ceramic ALON. However, till the late 1990s, most of the research and development work pertaining to these ceramics remained within the laboratories. Both these ceramics are now available commercially in developed economies such as the U.S. due to the efforts taken for commercialization over the past 10 years coupled with rising interest from aerospace and defense industries.
Some of the key players involved in the transparent ceramics market include Bright Crystals Technology, Ceranova, General Electric, Murata Manufacturing, Koito Manufacturing, and Coorstek.