Preparation Technology of Alumina Ceramic Feed in Injection Molding Process

Injection molding is a commonly used molding method for some special-shaped alumina ceramic parts, which can prepare various special-shaped ceramic materials. In this process, the feed preparation and technology of alumina ceramics are also very important. Below, Kezhong Ceramic Factory will introduce it to you.

Feed preparation involves mixing ceramic powder with an appropriate amount of organic carrier in a certain ratio at a certain temperature, then drying and granulating to obtain injection feed. The alumina ceramic feed used for injection molding needs to have a sufficiently high solid content, good rheological properties, and thermodynamic stability. The performance of the feed mainly depends on the properties of the powder and the selection of the binder, therefore, research and optimization of it are also focused on these two aspects.

Alumina ceramic parts

Powder properties

The average particle size, loose density, powder shape, specific surface area, and particle gap of the powder determine the properties of the prepared feed, which in turn affects the quality of the final product. For alumina powder, the most important requirements are small particle size and regular shape. This type of powder has good flowability, large filling capacity, and low sintering shrinkage during injection molding.

Research has shown that when the solid content of the alumina ceramic feed is the same, the amount of binder required to wrap the alumina powder decreases with the decrease of the specific surface area of the powder, making it easier for the powder to flow between them and reducing the viscosity of the feed, which is conducive to the completion of the injection process.

binder

Binder is the carrier of ceramic powder, which determines the rheological and injection properties of feed injection molding. A good adhesive can maintain the shape and effectively reduce the occurrence of embryo deformation and degreasing defects.

Aluminum oxide ceramic injection molding binder must meet the following conditions:

(1) Good flow characteristics, moderate viscosity during injection molding, and the viscosity should not fluctuate too much with temperature to reduce defect generation;

(2) Good wettability and adhesion to powder;

(3) High thermal conductivity and low thermal expansion coefficient;

(4) It is generally composed of multi-component organic compounds, and a single organic binder is difficult to meet the flowability requirements.

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