辽宁What influence does the purity of diamond micro-powder have on its performance?

Diamond micro-powder, as a core raw material in the field of superhard materials, its purity index directly determines its performance in high-end fields such as precision processing, semiconductor manufacturing, and optical devices. From the integrity of the crystal structure to the quality of the machined surface, from tool durability to thermal stability, purity runs through every application stage of diamond micro-powder, becoming the core yardstick for measuring its quality.

The synergy effect of purity and crystal structure

High-purity diamond micro-powder (purity > 99%) ensures the integrity of its crystal structure by strictly controlling the content of metal impurities (such as iron and copper) and harmful substances (sulfur and chlorine). Take polycrystalline diamond composite sheets (PCD) as an example. When the volume content of diamond reaches over 98%, the remaining 2% of the catalyst metal needs to be evenly distributed at the grain boundaries. If magnetic impurities remain in the raw material micro-powder, it will cause uneven distribution of the metal molten pool during the sintering process, forming graphitization defects or metal inclusions, reducing the hardness of the PCD layer by 15% to 20% and the wear resistance by more than 30%. Experimental data shows that PCD synthesized with micro-powder of 99.5% purity has a cutting efficiency 25% higher than that of the product with 98% purity, and the tool life is extended by 40%.

The purity dependence of surface processing quality

In the field of semiconductor wafer polishing, the influence of purity on surface roughness shows an exponential correlation. A 0.1% metal impurity in low-purity micro-powder can form micron-level scratches on the silicon-based surface, resulting in a 12% decrease in the yield of chips. For high-purity products, the magnetic susceptibility is detected by electromagnetic induction (which should be less than 0.05×10⁻⁸ m³/kg), which can avoid the phenomenon of particle agglomeration. Take the polishing of 12-inch wafers as an example. Using micro-powder with a purity of 99.9% can control the surface roughness below 0.2nm, meeting the requirements of the 5nm process technology, while products with a purity of 99% can only reach the 0.5nm level.

The quantitative relationship between thermal stability and purity

In high-temperature processing scenarios, purity directly determines the graphitization threshold of diamond micro-powder. Thermogravimetric analysis (TGA) indicates that the micro-powder with a purity of 99% begins to undergo graphitization transformation at 800 ° C, while the product with a purity of 99.9% can raise this temperature to 950 ° C. In the honing process of automotive engine blocks, the use of diamond grinding wheels with high-purity micro-powder can increase the linear speed from 35m/s to 50m/s, improve the processing efficiency by 43%, and at the same time reduce the tool wear rate by 60%.

The technical path for purity control

The current industry achieves impurity control through a three-stage purification process: acid washing to remove metals (hydrochloric acid: nitric acid =3:1), high-temperature oxidation to decarbonize (800℃ air atmosphere), and electromagnetic separation to demagnetize (magnetic field strength ≥0.5T). A leading enterprise adopted the laser diffraction method to detect the particle size distribution (deviation of D10/D50/D95 < 5%), combined with the scanning electron microscope (SEM) to observe the particle morphology, successfully controlling the magnetic impurity content below 0.001%. Its products have been applied in the processing of third-generation semiconductor silicon carbide substrates.

From crystal growth kinetics to surface physicochemistry, from macroscopic processing performance to microscopic defect control, the purity indicators of diamond micro-powder are driving the super-hard materials industry towards nanometal-level precision. As emerging fields such as 5G communication and new energy vehicles put forward higher requirements for processing accuracy, purity control technology will become an important manifestation of an enterprise's core competitiveness. In the future, customized micro-powder products with high purity (> 99.9%), narrow particle size distribution (D95-D10 < 10μm), and specific morphology (quasi-spherical or multi-edge structure) will become key basic materials in the high-end manufacturing field.