Branches of Ceramics

Ceramics and glass are typically classified according to two main categories based on end-use application: traditional products versus advanced/technical products. Traditional ceramics and glass, which are summarized below, consist of products that have been used since ancient times for construction, decoration, furnishing, food and beverages, transportation, and industrial applications. Ceramics include refractories, structural clay products, whiteware, earthenware (i.e., pottery), abrasives, and cements, whereas glass includes primarily flat, container, and pressed and blown glass.

From a market standpoint, cements are the largest category, at approximately $340 billion globally in 2018, followed by structural clay products at $135 billion. Both of these groups of products find their main application in the construction sector. Cement products include mainly Portland cement in addition to concrete and mortars. New cement products focus on CO2 reduction and ultrahigh performance. Structural clay products include many type of tiles (e.g., floor, wall, decorative, and roof), construction bricks (i.e., nonrefractory bricks), and other unconventional shapes, such as drainage, sewer, and chimney pipes and linings.

Refractories constitute another relevant class of traditional ceramics, with estimated sales of $36 billion in 2018. Refractories are defined as materials for high temperatures applications (1,000°F or above). In addition to being heat-resistant, they must also be able to withstand harsh conditions such as corrosion, abrasion, thermal shock, and mechanical impact. Refractories are used as bricks and liners for kiln and furnaces as well as molds, crucibles, ladles and other high-temperature items. They find application primarily in the metallurgical sector (for both ferrous and nonferrous metals), and also in other industrial sectors such as glass, ceramics, and cement manufacturing and power generation.

Traditional glass is also a large market at approximately $105 billion in 2018. Traditional glass includes products such as flat glass for construction and transportation (e.g., windows, facades, doors, windshields, security glass, control glass, and smart glass); container glass (e.g., bottles for beverages and perfumes); pressed and blown glass (i.e., tableware glass); glass fibers (used primarily as reinforcing agents); and other glass for household use and consumer products (e.g., mirrors and glass for furniture, glass for lighting fixtures, decorative and art glass, and eyewear).

By comparison, advanced ceramic and glass materials comprise products used in nontraditional industries. Many of these products were introduced after World War II to meet the requirements of fast-growing industry sectors such as electronics, optoelectronics, energy, and healthcare.

In recent years, the terms technical or engineered are increasingly being used instead of the term advanced to designate these products. In fact, the word advanced most often indicates recently developed and innovative manufactured products. For example, solar-control glass is a type of flat glass and therefore falls within the traditional ceramic/glass category, but it is also considered an advanced product because it is obtained by applying very thin films to the glass to modify its refractive index and reflect infrared radiation. Another example of a traditional but advanced ceramic is represented by tiles that incorporate photovoltaic cells.

From a market standpoint, the three largest categories of technical ceramics are electroceramics, structural ceramics and ceramics for extreme environments, and medical ceramics.

Electroceramics are products in which the ceramic is utilized for its electrical properties, typically for its insulating properties and its capacity to store electrical energy (dielectric properties). Although ceramics are traditionally considered to be insulators, their composition can be tailored to exhibit semiconducting, conducting, piezoelectric, or magnetic properties as well.

As such, ceramics find numerous applications in electronic and electrical applications, either as components of circuits (e.g., capacitors, inductors, and resistors) or as circuit devices (e.g., low-temperature co-fired ceramics [LTCCs]). Circuit boards and modules containing these components are ubiquitous. These components and devices also are used to manufacture intelligent systems for defense and security and many types of sensors.

Structural ceramics and ceramics for extreme environments include a variety of items such as friction products (e.g., ceramic brakes), cutting inserts, and other wear and corrosion resistant products. The most popular, however, are filtration media (i.e., filters and membranes), catalysts, and catalyst carriers (i.e., substrates and media that support the catalyst). Catalysts are used in petroleum refining, chemical processing, and automotive emissions control, whereas filtration media find applications in separation processes (e.g., water and wastewater filtration).

Medical ceramics are becoming quite popular as well. Dental ceramics have been available for some time, while ceramic parts and coatings for hip, knee, joint, cranio-maxillofacial, and spinal implants have recently found increasing use driven by a rising number of orthopedic procedures, primarily due to a rapidly expanding elderly population worldwide and by the growing availability of these procedures in developing countries.