In the production process of wear-resistant ceramics, the commonly used forming methods include dry pressing and isostatic pressing. Dry pressing, also known as molding, is one of the most commonly used forming methods. In the production process of wear-resistant ceramics, dry pressing is to put powder with good fluidity and suitable particle gradation after granulation into the metal mold cavity, and apply pressure through the indenter, and the indenter is displaced in the mold cavity. The pressure is transmitted, so that the powder particles in the cavity are rearranged and deformed and compacted to form a ceramic green body with a certain strength and shape.
The essence of dry pressing is that under the action of external force, the particles approach each other in the mold, and the particles are firmly connected with the help of internal friction to maintain a certain shape. This internal frictional force acts on a thin layer of binder around the particles that are close to each other. As the pressure increases, the blanks will change shape, slide against each other, reduce the gap, gradually increase the contact, and stick to each other. As the particles get closer together, the force between the colloidal molecules and the particles is strengthened, so the green body has a certain mechanical strength.
Features of dry pressing
Advantage：The dry pressing process is simple, the operation is convenient, the cycle is short, the efficiency is high, and it is convenient for automatic production. The embryo body produced by dry pressing also has the characteristics of high density, accurate size, small shrinkage, high mechanical strength, and good electrical properties.
Shortcoming:Dry pressing is difficult to apply to the production of large-scale embryos, and it has large wear on the mold, complex processing, high cost, and a relatively single pressure direction. It can only be pressed up and down, and the pressure distribution is uneven, resulting in uneven density and uneven shrinkage of the embryo. , will produce cracking, delamination and other phenomena.
Dry pressing has distinct characteristics and a wide range of applications. According to the principle and characteristics of dry pressing, we can improve the process in the production process, or use more advanced isostatic pressing instead of dry pressing to improve wear-resistant ceramics. Embryo mass.