珲春What are the surface treatment technologies for diamond micro-powder?

With the advancement of manufacturing towards high-end and precision, as well as the rapid development of fields such as semiconductors, photovoltaics, and precision processing, the surface treatment technology of diamond micro-powder, as a key functional material, has become a core link in enhancing tool performance and extending service life. At present, the surface treatment technology of diamond micro-powder has formed a diversified system, covering various methods such as electroless plating, electroplating, magnetron sputtering, vacuum micro-evaporation, and thermal explosion reaction. Among them, electroless plating and electroplating have become the mainstream choices in the industry due to their mature processes and strong controllability.

Electroless plating: A "molecular surgery" for Constructing Dense metal coatings

Chemical plating involves the catalytic reduction of metal ions in the plating solution by a reducing agent, which deposits a uniform and dense metal coating on the surface of diamond. Take electroless nickel-phosphorus (Ni-P) alloy plating as an example. The composition of its plating solution includes main salts (nickel sulfate, nickel chloride, etc.), reducing agents (sodium hypophosphite), complexing agents (succinic acid, citric acid), buffers, stabilizers, etc. The proportion of each component needs to be precisely controlled to optimize the performance of the coating. For instance, the sodium hypophosphite system requires the diamond surface to have catalytic activity, but diamond itself does not have this property. Therefore, a four-step pretreatment process of "degreasing - roughening - sensitization - activation" is needed: degreasing to remove surface oil stains, roughening to form tiny pits to enhance adsorption capacity, sensitization to adsorb easily oxidized substances, and activation to deposit palladium ions as catalytic centers. After electroless nickel plating, although the phosphorus element in the coating enhances corrosion resistance, it reduces electrical conductivity, affecting the subsequent sanding process. Therefore, it is necessary to further optimize it in combination with electroplating.

Electroplating: "Current engraving" for precise Control of Coating thickness

Electroplating deposits metallic nickel on the surface of diamond through electrolysis, forming a phosphorus-free conductive coating. The core lies in controlling the concentration of the main salt, the proportion of anodic active agents (nickel chloride, sodium chloride) and buffers (boric acid) to balance the deposition rate and the quality of the coating. For instance, an excessively high concentration of the main salt can lead to coarse grains in the coating and a decline in dispersibility, while a concentration that is too low is prone to cause temperature runaway. In response to the problem that fine-grained diamond micro-powder is prone to floating, the industry has developed a rotating electrode method: by rotating the cathode, the contact area between the electrode and the particles is increased, significantly improving the uniformity of the coating, and the production efficiency is increased by more than 30% compared with the traditional barrel plating method.

Composite technology: "Collaborative Innovation" Breaking through Single processes

To meet the demands of ultra-precision processing, composite processing technology has become a new trend. For instance, a nickel-phosphorus layer is first deposited on the surface of diamond through electroless plating to enhance electrical conductivity, and then electroplating is used to thicken the coating and improve wear resistance. Or it can be combined with magnetron sputtering to generate a carbide transition layer on the surface of the coating, further enhancing the adhesion between the diamond and the substrate. In addition, the sol-gel process can coat nano-scale metal oxide ceramic films on the surface of ultrafine diamond, significantly enhancing the dispersion stability, and is suitable for the preparation of high-end resin-based composites.

Application Expansion: The "All-Rounder" from Industrial Cutting to Cutting-edge Fields

Diamond micro-powder after surface treatment has permeated high-end fields such as semiconductors, photovoltaics, medical care, and aerospace. In semiconductor manufacturing, blades coated with diamond micro-powder can achieve micron-level cutting of silicon wafers. In the photovoltaic industry, coated diamond wire saws increase the efficiency of monocrystalline silicon slicing by 3 to 5 times. In the medical field, nano-scale diamond-coated tweezers can prevent wafer contamination, while 8-micron coarse particles are used for precise grinding of titanium alloy joints.

In the future, with the refinement of particle size classification (such as 17 grades for particles below 4 microns) and the strict regulation of particle size tolerance (within ±1 micron), the surface treatment technology of diamond micro-powder will evolve towards higher precision and better performance, providing key material support for high-end manufacturing.