Through the joint research with Cenotec Co., Ltd, the research team, led by Dr. Yuho Min and Dr. Jong-jin Choi in the Department of Functional Ceramics, Ceramic Materials Division at the Korea Institute of Materials Science, succeeded in developing the assembly control technology of nanoscale zirconia super-particles. In addition, the researchers developed a technology to convert the particles into ultra-small ceramic microparticles with high hardness,high density, and high modulus of elasticity.

The technology can control both colloidal suspension dispersion stability of nanoparticles and assembly speed at the same

time thereby manufactures ultra-small ceramic spherical assemblies with very high sphericity and density. By controlling the

sintering process, the technology can improve the hardness, density, and modulus of elasticity of ceramic materials while

maintaining sphericity.

The newly developed ultra-small ceramic microparticles have the most outstanding hardness among existing ceramic bulk and

film materials of yttria-stabilized zirconia manufactured by various processes. The sphericity and theoretical relative density

are more than 99% and 98%, respectively. If the technology for manufacturing and commercializing ultra-small ceramic

beads is developed, Korea will be in possession of the technology of manufacturing ultra-small and high-hardness ceramic

beads of 30 micrometers or less. The market is currently monopolized by Japanese companies.

Recently, to miniaturize core raw material powder into nano particles and to integrate parts in various high-tech industries

such as electricity and electronics, energy and environment, the demand for ultra-small (30 micrometers or less) beads is

rapidly increasing. In particular, in the case of multi-layer ceramic capacitors (MLCC) for automotive application, it's necessary

to make nano-miniaturization and high-purity of raw material powder for high performance. Therefore, there are growing

demand for smaller beads and higher hardness at the same time in order to withstand a strong impact.

The existing ceramic bead manufacturing technology is limited to manufacture ultra-small ceramic beads of 30 micrometers

(㎛) or less. Including making the size smaller, high hardness and high density are required for high purity and miniaturization

of the pulverized material. In addition, it is also important to have precise size control and high sphericity.

The researchers manufactured an ultra-small ceramic assembly with high sphericity and high density based on supraparticle

engineering technology using a spray drying technique for mass production. In addition, by controlling the sintering process,

the team succeeded in converting the assembly into ceramic microparticles with improved hardness and elastic modulus. The

hardness of the microparticles was about 27 gigapascals (GPa), which was the most outstanding value among the materials

having the same composition but developed by other processes. The modulus of elasticity was also an excellent value of 210

gigapascals (GPa).

As ceramic bead is a core technology for manufacturing and processing nano ceramic powder, the global market for ceramic

beads is rapidly growing at an average annual rate of 8.0% from USD 380 million in 2016 and is expected to reach about

USD 636.3 million in 2023. Even though the ceramic bead market is not that large, but if there was a suspension of supply

such as Japan's recent export restrictions to Korea, it would be impossible to produce parts related to multi-layer ceramic

capacitors (MLCC) and secondary batteries, which may create a huge ripple effect.

Dr. Yuho Min, a senior researcher at KIMS who led this R&D project said, “With our development of a technology for

manufacturing ceramic microparticles with high density, high hardness, and high sphericity, Korea took a step forward to

manufacturing super-small ceramic beads which are monopolized by Japan.” “The technology can be used in various industrial

fields without depending on Japan,” he added.