Technical Ceramic Refractory & Anti‑Thermal Shock

When an engineer specifies a material that has to withstand an instantaneous (or very rapid) temperature change between ambient (room) and 1200°C, the discussion quickly turns to ceramics and their ability to withstand thermal shock. Advanced ceramics not only have the capability of withstanding high temperatures, but also can withstand the extreme thermal gradients present when the materials are in service in furnaces, kilns, or as high-power electronic components without cracking; understanding how the material has a high resistance to cracking can help you determine which ceramic to use in your application, such as your manufacturing processes for multilayer ceramic capacitors (MLCC), the lining of a furnace, or in a sensor that will operate within a jet engine.

What Are Technical Ceramic Refractory Materials?

"Technical Ceramics are engineered, non-metallic, inert inorganic compounds made from oxides, carbides, nitrides and borides that have been processed under very tight controls to achieve targeted properties. When a ceramic is classified as being "refractory", it is capable of maintaining mechanical strength, being chemically inert and having dimensional stability at temperatures exceeding 1000°C. The most common refractory technical ceramic materials are alumina (Al₂O₃), zirconia (ZrO₂), as well as silicon carbide (SiC) and aluminium nitride (AlN), which are the foundation for current processing of very high temperature ceramic parts, including advanced multilayer ceramic capacitors (MLCC's) and molten metal casting.

Why Anti‑Thermal Shock Resistance Matters

Ceramics suffer from thermal shock when they are heated/cooled at different temperatures or amounts, causing internal tensile stresses that can exceed their fracture strength. High-performance thermal-shock resistant materials utilize high thermal conductivity, low CTE, and high fracture toughness to prevent catastrophic failure. MLCC manufacturers need to make green tapes from ceramic without cracking or delaminating during a fast binder burnout step and a quickly paced sintering step, while kiln furniture suppliers use setter plates that cycle between room temperature and firing temperature thousands of times over the course of their life-cycle. If either case fails due to thermal shock resistance the resulting product will be lost yield and scrap material.

Common Technical Ceramic Refractory Materials and Their Properties

No one type of ceramic can do everything the best. Below is a table that compares the thermal shock (and refractory) properties of the types of ceramics most commonly used in the industrial and electronic world.

For applications that demand rapid heating and cooling — such as the sintering process in an MLCC production line — the choice of technical ceramic refractory setter plates directly influences throughput and yield. Our guide to different types of sintering furnaces explains how furnace design and ceramic kiln furniture interact to achieve precise temperature profiles.

How Technical Ceramics Support MLCC and LTCC Production

All MLCCs are made up of many layers stacked together with a dielectric ceramic material (most often barium titanate), co-fired with nickel electrodes at very high temperatures (near 1300 degrees Celsius). Equipment used to process these green tapes and sintered components must be produced from technical ceramic refractory material so that no contamination occurs due to physical/chemical interaction between the equipment and the components. Uppershell's ceramic tape casting machines, automatic screen printers, and precision laminators are all designed considering this material property. The guide rollers, doctor blades, and lamination platens will also be designed so that they maintain their dimensional stability when processing tapes destined for further processing through extreme sintering conditions. To understand the complete journey from raw powder to finished multilayer component, our comprehensive look at the tape casting process for ceramic details every step, including the critical binder burnout and sintering phases where anti‑thermal shock properties are tested.

Frequently Asked Questions

What is an anti‑thermal shock ceramic?

Thermal shock-resistant ceramics are engineered to not only avoid cracking from temperature changes but also have an excellent ability to endure thermal shocks. The material does this by having two key attributes: having high levels of heat-conductivity (which allows for an immediate equalizing of interior and exterior temperatures) along with a high level of thermal expansion (this prevents dimensional change when heated or cooled). Silicon Carbide and Aluminum Nitride are both examples of successful ceramics with high levels of thermal shock resistance.

Which technical ceramic refractory material has the best thermal shock resistance?

The best thermal shock-resiSANT material for high temperature use within dry or air environment will generally be silicon carbide because of its extremely high thermal conductivity and low thermal expansion coefficient. However, for thermal shock-resisting materials/ceramics used in inert/reducing atmosphere environments, silicon nitride and aluminum nitride exhibit combined good performance for thermal shock because of their relative values of thermal conductivity and expansion coefficients. If good electrical insulating properties are necessary along with good thermal shock properties, then use AlN over Si3N4.

Can alumina be used in high‑thermal‑shock applications?

Alumina has reasonable thermal shock resistance due to its medium thermal expansion coefficient and heat conductivity. Its medium thermal conductivity and strength for high temperature applications add to alumina's ceramic properties create low-cost materials with very good chemical stabilization that make it an acceptable choice in situations where you can control both heating and cooling rates. Material engineers will frequently use SiC or AlN in situations that are required for much more extensive thermal cycling.

How does thermal shock affect multilayer ceramic capacitors (MLCCs)?

The process of making an MLCC ceramic involves two phases; the burning out of the binders from the green tape during the drying period and high temperature sintering after that has occurred. If the ramp up rate to the desired firing temperature is very rapid, the thermal shock due to thermal expansion helps create micro cracking in between the dielectric and internal electrode layers creating a condition where delamination, capacitance loss or total short circuit failures may occur. In an effort to reduce transient stresses to a level that is acceptable with respect to the specific physical form of the dielectric being processed, the process engineers will optimize the temperature profile as well as the kiln furniture material to maintain transient stresses within acceptable limits for the specific dielectric material to be processed.

Choosing a ceramic refractory material can have a large impact on your manufacturing process and equipment longevity since these materials can provide a combination of high-temperature strength and thermal shock resistance. Selecting the right ceramic will increase your equipment's lifespan, decrease scrap material costs, and stabilize processes that transition from extreme heat to ambient temperature. Whether you are selecting setter plates for a sintering furnace, a substrate for a power module, or a ceramic part that will experience thermal cycling on an ongoing basis, it is important to understand how the characteristics of the ceramic, such as its thermal expansion, thermal conductivity, and mechanical strength, interact with each other so that your overall design can avoid the possibility of failure. By using Uppershell's equipment, you will have access to the knowledge of how to properly select ceramic materials for use in your production line and to ensure that all of the machine components used in conjunction with the ceramic are capable of performing to the required specifications.