Advanced technical ceramics are widely applied in different industries, including electronics, aerospace, biomedical, and machinery because of their fine structure and excellent properties such as high hardness, wear resistance, corrosion resistance, high strength, and high temperature resistance.
During the production of different parts made of ceramic powder, technical ceramics manufacturers apply the process of sintering, which plays an essential role as it transforms bulk materials or the green body into compact solids, achieving the required mechanical and physical properties. Keep reading to learn more about the technology of sintering.
How does sintering work in ceramics?
Sintering helps produce density-controlled parts and deeply affects their final properties. It’s a thermal process that involves heating ceramic powders to a temperature below their melting point, causing the particles to bond together. This process enhances the material’s strength, reduces porosity, and improves its overall mechanical and thermal properties. It typically takes place at high temperatures, ranging from 1,832–3632°F, depending on the composition of the ceramic material.
Stages of sintering
Sintering occurs in three primary stages:
- Initial stage: At this phase, particle bonding begins as the ceramic powder is heated, leading to surface diffusion and the formation of necks between particles.
- Intermediate stage: Mass transport continues, densification occurs, and pores begin to shrink as particles further coalesce.
- Final stage: Pores become closed off, and the structure achieves near-full density, resulting in a stronger, more resilient material.
Types of sintering processes
There are several sintering methods used in advanced ceramics, depending on the specific application and material requirements:
- Conventional sintering: This method involves heating ceramic powders in a furnace under controlled atmospheric conditions. It’s widely used for various types of ceramics, but can sometimes lead to grain growth, affecting the final properties of the material.
- Pressure-assisted sintering: Techniques such as hot pressing (HP) and hot isostatic pressing (HIP) apply pressure during the process, which leads to better densification and finer grain microstructures.
- Spark plasma sintering: This is a rapid method that uses pulsed electrical currents to enhance diffusion and bonding, reducing processing time and preserving finer microstructures.
- Microwave sintering: Uses microwave energy to heat the material, resulting in faster sintering cycles and energy savings compared to conventional methods.
Factors that influence sintering
Several factors can influence the efficiency and outcome of the process, including:
- Temperature: Higher temperatures generally lead to better disinfection but can also promote excessive grain growth.
- Time: Longer durations can improve bonding but may also cause defects or undesirable microstructural changes.
- Atmosphere: Controlled environments (vacuum, inert gases, or reducing atmospheres) help prevent oxidation or unwanted chemical reactions.
- Particle size: Finer powders sinter more effectively due to increased surface area, enhancing material strength and density.
Applications of sintered ceramics
Sintered ceramics are used across multiple industries for their superior properties. Some key applications include:
- Aerospace: High-temperature resistant components such as turbine blades and thermal barrier coatings.
- Medical: Biocompatible implants like dental ceramics and artificial joints.
- Electronics: Substrates, insulators, and semiconductors for high-performance electronic devices.
- Automotive: Wear-resistant engine components and cutting tools.
Looking for a trusted technical ceramics manufacturer?
Looking for a trusted If you’d like to learn more about how to improve thermal shock resistance in technical ceramics, you’re curious about high-performance ceramics for extreme environments, or want to learn more about zirconia and alumina ceramics, reach out to our expert team at Wunder Mold. With comprehensive knowledge and years of experience, we can help you create the part that matches the exact requirements of your application. We work with both domestic and international clients. Contact us by phone or email at sales@wundermold.com and we’ll work closely with you to help you get the best results.