Ceramics contains a wide variety of materials, divided into two general categories: Standard and advanced.
Ceramics are also categorized based on the combination, production methods, and application.
Remaining from Ancient Iran, especially after the emergence of Islam and our valuable historical architecture, shows the importance and special place of ceramic productions in the old days of this land. Many people believe that the antiquities of the ceramic industry are a good measure of a country's civilization. Iran's history of culture and civilization is closely related to its antiquities from the ceramic industry. Investigating the history of civilization and culture of Iran indicates that in both ancient and Islam eras, our country has always been the leader of art and industry civility and is a great agent in the development and growth of human civilization, and has always been a pioneer of the science and industry in the world.
Ceramics nowadays play a significant role in direct and indirect serviceability to other industries and poses a special place. Currently, ceramics are not limited to clay and have different types. In this paper, we want to introduce types of ceramic.
How do we classify ceramics?
Ceramics include a wide area of materials that can be classified into two general groups. Standard ceramics (clay, structural clay productions, clay-based refractories, cement, concrete, and glass) are the classification of materials that has progressed since the beginning of human civilization, and it also includes a major part of the industry. However, the tendency of the modern world is toward advanced ceramics, developed in less than a past century. The advanced ceramics group possesses technical, unique, delicate, and engineering functions and can be classified into functional (electrical, magnetic, optical) and structural (in ambient temperature and high temperature) ceramics. However, the boundary between standard and advanced ceramics is not correct. In addition to this general criterion, other criteria exist for the classification of ceramics, some of which overlap each other. In this section, we investigate some of the most crucial criteria for the classification of ceramics.
Read more: What is ceramic; properties, types, and functions.
1- Based on the combination:
- Oxidic ceramics: These ceramics are made of metal oxides, such as alumina, zirconia, and silica. These are known for their durability, high stiffness, and resistance to abrasion and corrosion.
- Non-oxidic ceramics: These ceramics are made of carbides, nitrides, borides, and other components such as silicon carbide, aluminum nitride, and titanium diboride. They are known for their durability, high stiffness, and resistance to corrosion and abrasion.
- Composite ceramics: These ceramics are composed of a combination of two or several different materials, like alumina and zirconia, or ceramic and non-ceramic materials, such as fiber-reinforced ceramic. They were designed to combine the desirable properties of different materials.
2- Based on crystal structure:
- Crystal ceramics: These ceramics have certain crystal structures and are classified based on the type of crystal structure, such as cubic, tetragonal, or hexagonal. Some examples of this ceramic are alumina, zirconia, and silica carbide.
- Glass-ceramics: These ceramics have a combination of crystal and glass phases. They are designed to an extent as crystallized, and some examples of them are Lucite-reinforced glass ceramic and lithium disilicate.
- Amorphous ceramics: Known as glass, these ceramics lack a specific crystal shape. We can name silica glasses and borosilicate as examples of these materials, which are produced by cooling melt.
3- Based on properties:
- Structural ceramics: These ceramics are used due to durability, rigidity, and resistance to high corrosion and are usually used in applications such as cutting tools, bearings, and biomedical implants.
- Electronic ceramics: These ceramics are used for electric conductivity, dielectric properties, and piezoelectric properties and are usable for applications such as capacitors, sensors, and actuators.
- Thermal ceramics: These ceramics are used due to the capability of resistance to high temperatures and are usually used in linings, furnace components, and thermal transducers.
4- Based on the fabrication method:
- Standard ceramics: These ceramics are fabricated using common fabrication techniques, such as casting and press, and include productions like brick, tile, and utensils.
- Advanced ceramics: These ceramics are produced using more advanced methods, including steam chemical deposition, cell-gel processing, and hot press, and include productions such as cutting tools, biomedical implants, and electronic pieces.
- Nanoceramics: These ceramics have nano-scale dimensions and unique properties such as durability, stiffness, and high thermal stability. They are manufactured using advanced methods such as cell gel and used in catalysts, sensors, and energy storage.
5- Based on the physical state
Ceramics can be classified based on physical state. In this method, the ceramic classification is divided into different types based on the use form:
- Ceramic powder: Ceramic powder is a substance made from ceramic particles. It is mostly used as the raw material for ceramic production through processes such as powder press, sintering, and hot press.
- Ceramic pieces: Ceramic pieces are 3D objects that are made of ceramic materials. Examples are ceramic tiles, ceramic utensils, and glasses.
- Ceramic fiber: Ceramic fibers are thin, flexible strings made of ceramic materials. These materials are used as reinforcement in composite materials, insulation in high temperatures, and filter.
- Ceramic coatings: Ceramic coatings are thin layers made of ceramic applied on the surface of a sublayer. They can be used to improve the properties of the surface of a sublayer, such as resistance to corrosion, resistance to abrasion, and thermal insulation.
- Ceramic composites: Ceramic composites are materials that are produced by combining two or several types of ceramic materials or by combining ceramics with other materials like steel or polymers. They can be used to achieve specific properties such as resistance, improving abrasion resistance, and reducing weight.
- Ceramic membrane: Ceramic membranes are thin and porous layers of ceramic materials that are used for filtration and separation. It is possible to use them to remove pollution from liquids and gases, as well as to separate different materials within a mixture.
In our country, ceramics are classified with different methods. The most common and correct classification of various branches of ceramic is as below:
1- Particular products and technical ceramics
2-Refractories
2- Thick products
4-Thin products
Types of delicate ceramics
The term delicate ceramic is equivalent to the English term "whiteware". Delicate ceramics include utensils, tiles, sanitary ceramics, insulators, and electric insulation.
Various utensils are available based on their porousness and color.
The first group of utensils is colored porous. This group is the oldest type of ceramic and has two types of majolica and clay. Since there is a significant amount of ferric oxide in these ceramics, their color tends to be red or brown. Both majolica and clay are made of clay at high temperatures (950 to 1100 C). The difference between clay and majolica is in their compounds.
The second group of utensils is white porous ceramics. Earthenware are white clay bodies and have different types of clay, limestone, and feldspar based on their compounds. The most desirable type of earthenware is feldspar. They have high cook temperatures, and as a result, their porosity is lower than other earthenware.
The third group of utensils is colored compressed ceramics. These bodies are compressed and colored and can be used in the clay of the roof, experimental bushes, and sewage pipes. The reason they are colored is that they have at least 70% secondary clay.
The last group, which is the largest group of these ceramics, is white compressed ceramics. This category is known as porcelain and chain wares.
Despite being regarded as equivalent, porcelain and chinaware are not the same. These two types of ceramics have two similar properties: both have a vitreous state and very low porosity. Also, both ceramics can be produced and used with or without glaze. Chinaware is porcelain categorized as soft porcelain. With its thin body and soft nature, this porcelain can be cut using a rasp; while porcelain cannot be cut like that. As mentioned earlier, porcelains are stiffer and are used in medical and industrial applications, while chain wares are only used in domestic and decorative applications.
Read more: What is porcelain ceramic; types and applications
Frequent classifications were presented for chinaware. This classification is conducted based on the application (doily, hotel, teeth, utensils, and sanitary chinaware) and based on the body type (chinaware, stoneware, bony, etc.) and sometimes based on properties (soft and stiff chinaware), as mentioned in the following:
- Chinaware classification based on functional nature, such as utensils, sanitary, technical, and porcelains
- China ware classification, based on the nature in terms of properties, such as soft and stiff chinaware
- China ware classification, based on the China ware cook temperature, such as high cook temperature (original China wares) and low cook temperature (fake China wares)
- China ware classification, based on formula, fuzzy nature, and microstructure of chinaware. All types of chinaware from this point of view are porcelain, bony, earthenware, vitreous, stoneware, and fake chinaware
Tiles are classified into two groups wall and floor. Floor tiles and wall tiles are usually made from stoneware bodies and limestone earthenware, respectively. Wall tiles are usually glazed, but floor tiles are classified into glazed and unglazed groups. Porcelain ceramics and anti-acid tiles are unglazed floor tiles. Despite all advantages of porcelain ceramic, it has different colors, patterns, shapes, and sizes, and that is why it is widely used in executing floors and facades of the building. We can classify this type of ceramic product into two groups: facade porcelain ceramic and floor porcelain ceramic.
Sanitary ceramics are classified into three groups: semi-vitreous and vitreous, refractory clay, and stoneware. The body being semi-vitreous or vitreous depends on the percentage of the formed created glass phase in the body and water adsorption. Water adsorption of vitreous bodies is less than 1%, and the water adsorption of semi-vitreous bodies is between 3 to 14%.
These bodies are electrical insulators and do not transfer electrical flow. As a result, they should have high electrical resistance along with considerable endurance. They are usually used in low frequencies. These bodies have a low porosity and water adsorption. The reason is that if they have a high water adsorption level, they absorb moisture from the environment. Present ions in the air enter the body and cause electrical conductivity. On the other hand, water adsorption causes dielectric waste.
Types of ceramic based on the combination
Types of ceramic based on compounds
Ceramics are chemically non-metallic and inorganic materials except carbon. Advanced ceramics can be divided into silicate, oxide, and non-oxide groups. Silicates such as kaolinite [AL2Si2O5 (OH)4] and molait [AL6 Si2O13] are silicate ceramics.
Oxide ceramics are from two types of simple and complex combinations. Simple combinations, such as alumina (AC2O3) and complex oxides like barium titanate (BaTiO3), are super conductive materials (YBa2Cu3O6+δ).
Non-oxides are carbides like silicon carbide (SiC) and boron carbide (B4C), nitrides like silicon nitride (S3iN4) and boron nitride (BN), borides like titanium diboride (TiB2), silicide such as molybdenum disilicide (MoSi2), halides such as lithium fluoride (LiF), the base compounds are nitride-oxide or oxynitride system like sialon.
Chemical methods that have passed the second type of significant steps of chemical purification are usually used for the synthesis of advanced ceramic powders from the synthesis or raw materials in the environment.
Types of ceramic in terms of the fabrication method
Ceramic materials can be categorized based on the different methods used to produce them. Some of the common methods are as below:
1- Press: In this method, ceramic powders are mixed with stabilizer materials and are compressed in the desired shape using the press. Then, they were sintered to a high temperature without the presence of pressure to create a compressed section. This method is used to produce ceramic components with complex geometry.
2- Extrusion: The ceramic paste in this method is formed using a continuous mold with a constant section. Then, the extruded shape is cut to the desirable length and sintered at a high temperature. This method is commonly used for the fabrication of pipes, tubes, and other cylindrical things.
3- Iso static press: This method is used to produce high-quality ceramics such as silicon carbide, boron carbide, and advanced ceramics. In this method, the powder ceramic is placed in a flexible mold. Then, a large isostatic pressure is applied from all directions to a raw and uniform body. It is then sintered to a high temperature to form the piece.
4- Slurry casting: In this method, the ceramic mixture is poured into a gypsum mold, and the water is adsorbed by the walls of the mold to create a solid and uniform ceramic layer. Then the extra slurry discharges, and the remaining ceramic layer exit from the mold and sinter at a high temperature. This method is used to produce ceramic tools with thin walls, such as plates, bowls, and glass.
5- Tape casting: This method is commonly used to produce ceramic layers in electronic applications, such as multi-layer capacitors, ceramic filters, and sensors. In this method, ceramic powder is mixed with the stabilizer substance and diffused as a thin, uniform layer. Then, the layer is dried, cut to the desired shape, and sintered to a higher temperature.
6- Injection molding: In this method, ceramic powder is mixed with a stabilizer and a dissolver and transformed into a plastic shape. Afterward, an injection device is used to inject ceramic materials into the intended mold. It is then sintered to a higher temperature to form the piece. This method is used to produce ceramic components with complex geometry and high performance, such as industrial pieces, automobile pieces, and airplane pieces.
7- Hot press: In this method, ceramic powder is mixed with a stabilizer material and compressed to the desired shape. This method is used to produce ceramic components with properties such as resistance to corrosion and heat, and abrasion.
8- 3D Print: In this method, a 3D printer is used to print ceramic pieces with ceramic powders and a stabilizer. The ceramic layer is printed layer by layer and sintered to a higher temperature. The benefit of this method is the piece fast production and producing pieces with very small or very large dimensions.
Types of ceramic based on corrosion-resistance
Ceramics can be classified into different types based on the corrosion resistance. Some of these classifications are:
Acid-resistant ceramics: These ceramics are resistant to acid and are used in chemical process industries. For example, we mention alumina, silicon carbide, and zirconia.
Alkaline-resistant ceramics: These ceramics are resistant to alkaline and are used in producing glass and cement. Some examples of this are magnesium and alumina.
Corrosion-resistant ceramics in high temperatures: These ceramics are resistant to corrosion in high temperatures and are usually used in gas turbine engines and furnaces. Alumina and zirconia are some examples.
Bioceramic: These ceramics are resistant to biological corrosion and are used in dental and medical uses as implants and prostheses. Hydroxyapatite and bioactive glasses are some examples.
Glass-ceramic: These ceramics are composite materials, which are a mix of properties of ceramic and glass. They are resistant to thermal shock and are used in utensils, oven windows, and the nose cone.
Porous ceramics: These ceramics have a high level and are used in the filtration and separation process. Alumina and silicon carbide are some examples.
Each type of ceramic has its unique properties, which makes them appropriate for particular uses. Corrosion resistance is a crucial feature for ceramics used in harsh environments, and selecting the ceramic type depends on the particular corrosion conditions.
Ceramic classification based on application
Ceramic materials are widely used in our daily lives, from utensils and cooking dishes to electronic equipment and cutting tools. They are usable for different applications due to their unique properties, and their usage has been developed following the continuous progress in the production and development of materials. Ceramic materials are widely used in the building industry due to their significant mechanical properties, durability, and resistance to corrosion and abrasion. These materials can be used as ceramic floors, wall tiles, etc. In this section, ceramics were classified in terms of applications.
Final word
In this paper, we became familiar with types of ceramics and observed that it is not limited to ceramic walls and floors. Standard ceramics include ceramics like chinaware and tiles, such as tile, floor, wall, ceramic sanitary tools, and other ceramic products, and engineering ceramics are for responding to special needs, such as higher thermal resistance, better mechanical properties, and special electric properties and chemical resistance. If you have any questions about ceramics that this article did not answer, you can ask them in the comments.
