井冈山How does diamond micro-powder improve the performance of coating materials?

Diamond micro-powder, through its unique physical and chemical properties, can significantly improve the performance of coating materials, which is specifically reflected in the following aspects:

1. Enhance the hardness and wear resistance of the coating

Hardness enhancement mechanism

Diamond micro-powder is the hardest substance in nature (with a Mohs hardness of 10). Introducing it into coatings can form a hard phase dispersion structure. For instance, in Ni-Mo-based composite coatings, the addition of diamond particles alters the growth pattern of the matrix metal, refines the grains and changes the preferred orientation, thereby enhancing the hardness of the coating. Experiments show that the hardness of the Ni/ diamond composite coating containing diamond particles is significantly higher than that of the pure Ni coating, and its wear resistance is increased by more than 30%.

Case of Wear Resistance Optimization

Tool coating: When depositing diamond coatings on the surface of cemented carbide tools, diamond micro-powder is pre-treated on the substrate through ultrasonic grinding to increase surface roughness and enhance the adhesion of the coating. The hardness of the coating after deposition can reach HV8000-10000, and its wear resistance is 5 to 10 times that of traditional coatings.

Engine blade coating: The coating prepared with nano-scale diamond micro-powder (size <100nm) can fill the pores of the coating due to the quantum size effect and surface effect of the nanoparticles, forming a dense structure and increasing the wear resistance of the coating by 40%.

2. enhance the corrosion resistance of the coating

Corrosion protection mechanism

The chemical inertness of diamond micro-powder makes it an excellent corrosion barrier. In metal matrix composite coatings, diamond particles can block the penetration path of corrosive media (such as Cl⁻), delaying the electrochemical corrosion reaction. For instance, the research by Sajjadnejad et al. found that the corrosion resistance of the Ni/ diamond composite coating in 3.5% NaCl solution was more than twice that of the pure Ni coating.

Application scenarios

Marine environment: Adding diamond micro-powder to the coating of ship propellers can effectively resist seawater corrosion and extend the service life by 3 to 5 years.

Chemical equipment: Introducing diamond micro-powder into the inner wall coating of storage tanks can reduce the corrosion rate of acidic media (such as H₂SO₄) and lower maintenance costs.

3. Improve the thermal conductivity and electrical conductivity of the coating

Thermal management optimization

Diamond micro-powder has an extremely high thermal conductivity (2000-2200 W/m·K), which can significantly enhance the heat dissipation efficiency in electronic packaging coatings. For instance, the coating prepared by combining diamond micro-powder with a copper substrate can achieve a thermal conductivity of 600-800 W/m·K, which is over 50% higher than that of pure copper coatings, meeting the heat dissipation requirements of high-power devices.

Enhanced electrical conductivity

The electrical conductivity of diamond can be improved by depositing a metal layer (such as nickel or copper) on its surface through electroless plating or electroplating techniques. For instance, the resistivity of diamond micro-powder after electroless nickel plating is reduced to the order of 10⁻⁶ Ω·cm, which can be used to prepare highly conductive electromagnetic shielding coatings.

4. Optimize the surface morphology and functionalization of the coating

The surface flatness has been improved

The particle size distribution of diamond micro-powder is crucial to the surface quality of the coating. By adopting particle size gradient control technology (such as final polishing of fine powder with D50=1μm), the surface roughness Ra of the coating can be made ≤0.02μm, achieving a mirror-like effect. It is suitable for high-precision processing scenarios such as optical lenses and semiconductor wafers.

Functionalization modification

Chemical modification: By ozone oxidation or treatment with silane coupling agents, functional groups such as hydroxyl and carboxyl groups are introduced onto the surface of diamond to enhance its interfacial affinity with organic polymer coatings. For instance, the dispersion of modified diamond micro-powder in epoxy resin coatings is enhanced, and the tensile strength of the coating increases by 25%.

Magnetron sputtering coating: Depositing metal layers such as titanium and chromium on the surface of diamond to form a carbide interface can significantly enhance the bonding strength between the coating and the substrate. Experiments show that the adhesion of the diamond coating after magnetron sputtering titanium plating can reach over 50MPa, meeting the high-strength requirements in the aerospace field.

5. Typical Application Cases

Semiconductor packaging

The coating prepared by combining diamond micro-powder with a metal substrate, when used as a heat dissipation substrate for semiconductor devices, can reduce the operating temperature of the chip by 10-15℃, enhancing the reliability and lifespan of the device.

Aerospace coating

Depositing a diamond coating on the surface of turbine blades can simultaneously enhance wear resistance, corrosion resistance and thermal conductivity, raising the operating temperature of the blades by 200-300℃ and significantly improving engine efficiency.

Automobile industry

Diamond micro-powder used in the coating of automotive piston rings can reduce the coefficient of friction to below 0.05, cut energy consumption by 10-15%, and extend the service life of the piston rings by 2-3 times.