Sintering is the process of compacting solid materials that result in a more durable, stronger, and harder mass due to pressure and high heat that force the atoms to bond more tightly with each other. It’s one of the essential machining processes applied by ceramic component manufacturers. Continue reading to learn more about the sintering method.

What is the powder sintering process?

During the process of sintering, ceramic powder particles undergo heating to a high temperature below the melting point, where their vapor-solid interface decreases, resulting in reduced surface energy of the particles. The existing pores diminish or fully close up, creating a higher-density material and improving the mechanical properties of the part.

ceramic component manufacturers

The final level of porosity depends on the green compact’s initial porosity, as well as the temperature and duration of sintering. Pure oxide ceramics require longer time and higher temperatures since particle diffusion occur in the solid state. Also, applying pressure reduces sintering time and porosity.

The process of sintering is considered successful when it results in reduced porosity and enhanced translucency, strength, thermal conductivity, and electrical conductivity of the material. In specific cases, careful application of sintering can improve the strength while preserving porosity.

What are the stages of sintering?

The base principles of sintering involve:

Powder composing

This is the stage where you determine the composition of your ceramic parts by mixing water, deflocculant, binder, and unfired ceramic powder to create a slurry which is then spray-dried. The properties of powdered materials will affect the final characteristics of the part, such as strength, hardness, and temperature conductivity.

Powder compacting

Compaction can involve different processes of mechanical densification through cold or hot mold pressing that result in the green part. Compaction allows for the efficient production of components with tight tolerances due to low drying shrinkage.

Sintering or firing

The green part further goes through a tunnel kiln or periodic kiln for heating. In a periodic kiln, the components go through heating and cooling stages according to a set system. A tunnel kiln conveys the parts through three different temperature zones:

  • Preheat zone removes lubricants and other organic materials.
  • Sintering zone is where atom diffusion occurs to fuse the particles together and create a solid piece.
  • Cooling zone allows the part to cool down.

Sintering can be done with or without an external force such as pressure, which is commonly used. When it’s performed only by heating, it’s referred to as pressureless sintering, and it’s possible with metal-ceramic composites.

You can separate the parts using special separator sheets for efficient product stacking during the process of sintering. The sheets are available in different materials such as magnesia, alumina, and zirconia. They’re also categorized by particle size, including coarse, medium, and fine.

You can reduce surface damage and contamination of the parts and maximize furnace loading by matching the sheet particle size and material to the components.

Where can I find reliable ceramic component manufacturers?

What are the stages of sinteringWhen you need a trusted partner to create premium-quality parts according to your needs and specific requirements, Wunder Mold is your team to rely on. With over two decades of experience, we boast the knowledge and expertise necessary to deliver custom injection molded parts while adhering to the highest industry standards.

We’ll also be happy to provide you with answers to any questions you may have. Whether you’re wondering about the characteristics of zirconia toughened alumina, how ceramic powder is made, or how to test ceramic hardness, we’ll gladly let you know about it. Feel free to give us a call or send us an email at and let us know all about the parts you need.