Processing method of zirconia ceramic injection molding

In recent years, more and more precision structural components of zirconia ceramics have higher requirements for zirconia powder, leading to the concept of preparing nano zirconia ceramics. Nano zirconia ceramic ultrafine powder refers to an average particle size between 0.01-0.1μ M powder.

The preparation of nanometer powder can be generally divided into chemical method and physical method. Chemical methods such as Wet chemistry, chemical vapor phase, solvent evaporation, etc.

The core idea of zirconia ceramic injection molding is to form a low viscosity and high solid content concentrated suspension by uniformly mixing organic monomer solvents and ceramic powder. After adding coupling agents, catalysts, and initiators, the organic monomers in the material polymerize to form a three-dimensional network structure, thereby enabling the concentrated suspension to solidify in situ and obtain high-strength, high-density, and well homogeneous embryos.

In the early 1990s, the zirconia ceramic casting molding technology of valves in Oak Ridge National Laboratory in the United States met this requirement.

Zirconia ceramic materials are difficult to machine after sintering, and the processing cost is very expensive. Therefore, people have been searching for a near net size forming technology suitable for complex shaped ceramic structural components.

In fact, this is a clever combination of traditional zirconia ceramic injection molding process and organic chemistry theory.

The low viscosity and high solid volume content of concentrated suspensions in zirconia ceramics during injection molding are contradictory factors. Adding appropriate surfactants can change the surface negativity of solid particles, thereby altering the viscosity of concentrated suspensions.

Adding an appropriate amount of dispersant to zirconia ceramics can reduce the viscosity of the slurry, which is helpful for preparing low viscosity, high solid content slurry. Increasing the amount of dispersant within a certain range can continuously reduce the viscosity of the slurry, and there is a minimum viscosity value. As the solid phase volume content of zirconia ceramics increases, the particle spacing decreases, the repulsion between particles increases, and the amount of dispersant required also decreases

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