珲春How can the agglomeration problem of diamond micro-powder be effectively solved?

In the field of ultra-precision machining and advanced materials, diamond micro-powder, due to its super-hard properties, excellent thermal conductivity and chemical stability, has become a core consumable in high-end manufacturing such as semiconductor wafer cutting, optical component polishing, and aerospace composite material processing. However, diamond micro-powders with particle sizes ranging from nanometers to micrometers are prone to agglomeration due to excessively high surface energy, leading to poor dispersion and fluctuations in processing quality, which have become the key bottlenecks restricting their performance. In recent years, through the coordinated regulation of physical and chemical methods, surface functionalization modification and process innovation, the agglomeration problem of diamond micro-powder has been gradually and systematically solved.

Agglomeration mechanism: Dual challenges of surface energy and interfacial forces

The agglomeration of diamond micro-powder mainly stems from two aspects: one is the physical agglomeration driven by high surface energy, where particles spontaneously aggregate through van der Waals forces or electrostatic forces to reduce the total surface area; The second is hard agglomeration caused by chemical bonding, especially during the drying or calcination stage, when sintering necks or chemical bonds may form between particles, leading to irreversible adhesion. For instance, in polymer composites, agglomerated diamond micro-powders can become stress concentration points, reducing the mechanical properties of the material. In the polishing liquid, aggregates may scratch the surface of the workpiece, affecting the roughness control.

Solution: Multi-dimensional coordinated regulation

Surface charge regulation: The "Golden Range" of Zeta potential

By adjusting the pH value of the solution or adding electrolytes, the surface of diamond particles can be charged, and the repulsive force of the double electric layer can be utilized to suppress agglomeration. Research shows that when the absolute value of the surface Zeta potential reaches 30-50mV, the electrostatic repulsion between particles can effectively resist van der Waals forces, achieving stable dispersion. For instance, in semiconductor polishing liquid, by adjusting the pH to the alkaline range, the surface of diamond micro-powder becomes negatively charged, with a Zeta potential reaching -40mV, significantly enhancing the adsorption stability of particles and reducing scratch defects.

Dispersants and Surface Modification: The "Space Barrier" of Chemical Bonding

Introduce high-molecular dispersants (such as sodium polyacrylate, oleic acid) or surfactants to form a liquid film on the particle surface through adsorption, reducing interfacial tension and introducing steric hindrance. For instance, in the silicon carbide-diamond composite abrasive system, the application of oleic acid modification can enhance the dispersion of diamond micro-powder in paraffin oil by 60% and increase the cutting efficiency by 25%. In addition, chemical grafting techniques such as silane coupling agents can further enhance the compatibility of particles with the matrix and reduce the tendency of agglomeration.

Technological innovation: Blocking the path of agglomeration from the source

Wet grinding depolymerization: A wet grinding instrument with the minimum dosage is used. Through the combined effect of high-energy shearing and ultrasonic waves, the agglomerated weight after classification is re-dispersed into single particles. For instance, grinding 0.2μm diamond-coated ZrO₂ beads for 4 hours can reduce the aggregate size to less than one-third of the original particle size.

Low-temperature drying technology: Avoids the formation of hard aggregates in traditional drying. By using freeze-drying or nitrogen-protected drying, the slurry is rapidly frozen in liquid nitrogen and then vacuum-dried, which can reduce the formation of hydrogen bonds between particles and improve the dispersibility of diamond micro-powder by 40%.

Aggregate reuse: In response to the problem of overstocked inventory of fine-grained diamond micro-powder, the aggregate abrasive technology is adopted to aggregate it into larger abrasives, which demonstrate advantages such as low grinding force and high self-sharpening during processing. This not only increases added value but also alleviates the pressure of agglomeration.

Application prospects: The leap from the laboratory to industrialization

At present, the dispersion technology of diamond micro-powder has achieved a breakthrough from a single method to the integration of multiple technologies. For instance, in the polishing of semiconductor wafers, through the coordinated effect of Zeta potential regulation and dispersants, the suspension stability of diamond micro-powder in the polishing liquid can reach over 72 hours, meeting the full-process processing requirements of 8-inch wafers. In the processing of aerospace composite materials, the dispersion uniformity of surface-modified diamond micro-powder in the resin matrix is improved by 50%, significantly enhancing the thermal conductivity and wear resistance of the material.

With the surging demand for ultra-precision processing in emerging industries such as "low-altitude economy" and quantum computing, the agglomeration control technology of diamond micro-powder is evolving towards intelligence and greenness. In the future, by optimizing the dispersion process parameters through AI algorithms and developing environmentally friendly dispersants, the dispersion stability of diamond micro-powder is expected to break through the current limits, providing stronger material support for high-end manufacturing.