Microstructure of a kind of nano powder
overview
During the crushing process, the crushing of individual ceramic pigment particles is often carried out simultaneously with the crushing of other particles. Due to the difficulty in distinguishing which particles were crushed during the crushing process, the method of comparing the particle size distribution of the product with the particle size distribution of the original material was used to analyze the crushing effect.
Grinding technology is very important in the process of nanometer powder processing, and it is a necessary process step for pigment production. In order to understand the basis of particle crushing, it is necessary to first understand the mechanism and related concepts of single particle crushing after a certain amount of stress is applied.

Concept of fracture mechanics of particles
When studying the fracture mechanism of particles, relevant experts put forward the concepts of "fracture physics" and "fracture mechanics" as the branches of material science and particle mechanics. Particles are diverse and have defects from small to large. Therefore, due to the diversity of particles and their properties, particle crushing can essentially be described as a fracture process.
Diagram of the relationship between atomic constraints and distances
Under the action of external forces, the atomic bonding between the cleavage planes is disrupted, leading to brittle fracture of the crystal. Therefore, the theoretical strength of a crystal should be determined by the binding force between atoms. When the atoms are in an equilibrium position, the force between the atoms is zero; Under tensile stress, the atomic spacing increases and the gravitational force also increases. The highest point on the curve represents the binding force of the crystal, which is the theoretical fracture strength.
It is generally believed that ceramic pigment particles are brittle materials, and their fracture is caused by stress induced strain. According to fracture theory, defects (cracks, etc.) in materials can lead to stress concentration at the edge of the defect and at the crack location.
The crack tip (breaking point) has chemical bond with different bonding strength under external stress. Even though the applied stress is not enough to overcome the yield stress, it can provide enough energy to make the crack expand and produce a new surface. When the strain at the crack tip can make the new surface form, the particles will break.