Ceramic Materials

Ceramics, defined by the broad definition of “inorganic solids”, are one of the main classes of materials, along with metals, polymers, and composites. There are several different types of ceramics, with advanced ceramics (also known as engineered ceramics or advanced ceramics) being the group with the highest performing mechanical, electrical, and/or thermal properties. Their high performance is due in part to their extremely high purities which are most commonly metal compounds combined with oxides, carbides, or nitrides. Ceramics have the ability to increase product lifespan, increase efficiency, reduce overall maintenance costs, and improve performance.

High Hardness

One of the most common properties of engineered ceramics is extreme hardness (& stiffness) – some are more than 4 times harder than stainless steel. This high hardness directly translates into excellent wear resistance, meaning that many advanced ceramics have the ability to keep their precise, high-tolerance finish much longer than any other material.

Extreme Compressive Strength

Advanced ceramics have very high strength, however, this is only when compressed. For example, many advanced ceramics can withstand extremely high loads ranging from 1000 to 4000 MPa. Titanium on the other hand, which is regarded as a very strong metal, only has 1000 MPa of compressional strength.

Low Density

Another common property of advanced ceramics is their low density, ranging from 2 to 6 g/cc. This is significantly lighter than stainless steel (8 g/cc) and titanium (4.5 g/cc) with only the much softer aluminium being similar in density. Due to their high hardness and low weight, advanced ceramics are increasingly being used in a variety of industries in applications where no other material can match their performance & long life.

Excellent Wear Resistance

Many advanced ceramics are able to withstand incredibly high temperatures while still retaining their mechanical & electrical properties. Where all metals and polymers will start to compromise their properties, advanced ceramics will continue to function with consistent performance and reliability. This property makes ceramics appropriate for use in very high temperature applications like furnaces, jet engines, brake systems, and cutting tools.

Excellent Electrical Properties

Advanced ceramics tend to be excellent electric insulators (high dielectric strength). They are especially useful in high-temperature applications where other materials’ mechanical & thermal properties tend to degrade. Some ceramics have low electrical loss & high dielectric permittivity; these are typically used in electronic applications like capacitors and resonators. Additionally, the ability to combine an insulator with a structural component has lead to many product innovations.

Ultra-High-Temperature Ability

Advanced ceramics can function in situations where no metal (or nearly any other material) can maintain their properties. Some ceramics can operate in temperatures in excess of 1750°C, putting them in a class of their own as ultra-high-temperature materials. These ceramics have proven to be invaluable in high-temperature applications like engines, turbines, & bearings where they have increased the lifespan, performance, and efficiency.

Thermally Conductive or Insulative

Different types of advanced ceramic materials have wildly varying thermal properties. There are some ceramics (Aluminium Nitride) that are highly thermally conductive and are commonly used as heat-sinks or exchangers in many electrical applications. Other ceramics are much less thermally conductive, making them suitable for a wide range of applications.

Chemically Inert & Corrosion Resistant

Advanced Ceramics are very chemically stable and have low chemical solubility, making them highly resistant to corrosion. Metals and polymers cannot offer the same inertness or corrosion resistance, making ceramics a highly attractive option in many commercial and industrial applications, particularly when wear resistance is also needed.

Poor Shear & Tensile Strength

With all of these advantageous properties, you may be wondering why we do not see advanced ceramics more frequently. This is due to a variety of reasons, but mostly because other types of strength are tensile and shear; this is where advanced ceramics strength can be 15 times less than those of metals.

High Brittleness

Another issue that can arise with advanced ceramics is that they can be very brittle due to their low ductility. This means that advanced ceramics have very poor impact resistance. This property is caused by advanced ceramics unique atomic bonds. Metals have “metallic” bonds which are relatively low strength, however, they can bond with atoms in any direction. This ability to have many multi-directional bonds is what makes metals ductile, tough, and relatively strong. Ceramics obviously do not have metallic bonds, instead they have ionic and covalent bonds – these are very strong, however they can only bond in very specific directions. This highly organized bonding structure means that it is difficult for the atomic structure to shift, making ceramics not malleable.

Difficult to Design

Every type of advanced ceramic has specific thermal, mechanical, and electrical properties that can vary dramatically depending on the operating conditions & product design. In fact, even the manufacturing process of the exact same type of advanced ceramic material can drastically change its properties.

Precision Ceramics is unusual as we offer the full range of advanced ceramics from machinable grades like Macor and Shapal through to materials that require diamond grinding like alumina, zirconia, carbides and nitrides. We can machine and supply virtually any ceramic material – please contact us with your specific requirements for more information. Our goal it to optimize the material selection and design for the customer, rather than what is right for our capability.

Yes we can. We have a competent team of advanced sales staff with many years’ experience that can help you chose the right material and provide design consultation. Whether it is for wear, thermal management, electrical properties, or something else, we can help you by designing an appropriate component for ceramic manufacture from simple suggestions to more complex solutions. Contact us with details of your application and one of our engineers will be happy to help you.