辽宁How does diamond micro-powder achieve efficient polishing effects?

Diamond micro-powder, as the hardest material in nature, its polishing efficiency directly determines the limit in the field of precision machining. From semiconductor wafers to aerospace components, from optical crystals to cemented carbides, the core of high-efficiency polishing technology lies in the precise control of the particle size, shape and bonding mode of diamond micro-powder, as well as the collaborative optimization of processing techniques.

Particle size classification: Build a multi-level processing system

The particle size selection of diamond micro-powder is the basis of polishing efficiency. According to processing requirements, a "step-by-step reduction" strategy is usually adopted: in the rough polishing stage, 10-20μm micro-powder is selected to quickly remove material; in the medium polishing stage, 3-6μm micro-powder is switched to achieve surface smoothness; and in the fine polishing stage, 0.5-1μm ultrafine powder is used to achieve nano-level smoothness. For instance, in the polishing of silicon carbide substrates, 15μm micro-powder can reduce the surface roughness from Ra200nm to Ra50nm, while 1μm micro-powder can further optimize it to below Ra0.2nm. This grading processing system avoids the problems of low efficiency or surface damage caused by a single particle size through the logic of "coarse first, then fine".

Morphological control: The synergistic effect of single crystals and polycrystals

The crystalline form of diamond micro-powder directly affects the cutting behavior. Single crystal micro-powder has a sharp octahedral or rhombic dodecahedral structure and possesses extremely strong cutting force, making it suitable for the rapid removal of hard materials. For instance, in the polishing of sapphire substrates, single crystal micro-powder can increase the material removal rate to 3μm/min, but it is prone to causing micro-scratches. Polycrystalline micropowder is composed of nanocrystals ranging from 3 to 10nm in size, with no cleavage surfaces inside. Its toughness is significantly enhanced, enabling it to maintain high cutting efficiency while reducing scratches. Experiments show that when polycrystalline micropowder is used to polish optical crystals, the surface roughness can be reduced by 40% compared with single-crystal micropowder, and the tool life can be extended by 60%.

Process innovation: Chemical-mechanical composite polishing

Traditional mechanical polishing relies on the physical cutting of diamond micro-powder, while chemical mechanical polishing (CMP) achieves a synergistic effect of "chemical corrosion + mechanical removal" by introducing oxidants or catalysts. For instance, in the polishing of diamond single crystals, when the mixture of KNO₃ and NaOH is heated to 350℃, the molten salt forms an oxide layer on the surface of the grinding disc. Combined with the cutting effect of diamond micro-powder, the removal rate can be increased from 0.5μm/h to 5μm/h, and the surface roughness can be optimized from Ra100nm to Ra50nm. Although high-temperature molten salt poses a risk of equipment corrosion, this technology offers a new approach for polishing super-hard materials.

Tool Design: The balance between consolidation and dissociation

The carrier form of diamond micro-powder is crucial to the polishing efficiency. Solidified micro-powder grinding wheels fix micro-powder through resin, ceramic or metal binders to achieve high-precision control, but they are prone to efficiency decline due to the passivation of abrasive grains. Free micro-powder polishing is carried out in the form of suspension or polishing paste, allowing the micro-powder to freely roll on the processed surface, which is suitable for complex curved surfaces, but it has the problem of poor dispersion. The current industry trend is to develop agglomerated diamond micro-powder. Through a special process, the micro-powder is aggregated into micron-sized particles, which not only retains the flexibility of free micro-powder but also extends the tool life through the self-sharpening property of the agglomerated body. For instance, in the fine grinding of ceramics, agglomerated micro-powder can increase processing efficiency by 30% and reduce micro-powder waste by 60% at the same time.

Application scenario: The leap from the laboratory to industrialization

The efficient polishing technology of diamond micro-powder has permeated many high-end fields. In the semiconductor industry, 3μm diamond micro-powder polishing liquid is widely used for the final polishing of silicon wafers, achieving a surface quality of Ra0.1nm. In the aerospace field, polycrystalline diamond micro-powder grinding wheels are used for the precision grinding of titanium alloy blades, with a processing accuracy of ±0.005mm. In the field of consumer electronics, 0.1μm ultrafine powder polishing paste has become the core material for mirror surface treatment of mobile phone glass covers. With the rise of the "low-altitude economy" and the third-generation semiconductor industry, diamond micro-powder polishing technology is facing higher requirements, such as low-damage processing of carbon fiber composite materials and non-destructive polishing of gallium nitride substrates.

From particle size classification to shape control, from process innovation to tool design, the efficient polishing technology of diamond micro-powder is the cross-integration of materials science, mechanical engineering and chemical engineering. In the future, with the growth of demand for nanoscale processing, diamond micro-powder will develop towards finer particle size, higher purity and more complex forms, continuously driving precision manufacturing towards ultimate accuracy.