Why can green silicon carbide micro powder be used as a filler in insulating coatings?

Why can green silicon carbide micro powder be used as a filler in insulating coatings?

Green silicon carbide (GC, SiC purity ≥98%) possesses multiple advantages, including high resistivity, high temperature resistance, stable insulation, wear resistance, acid and alkali resistance, high thermal conductivity, and low thermal expansion. Unlike traditional insulating fillers such as talc, barium sulfate, and alumina, it is a core functional filler in four major categories of special insulating coatings: high-temperature insulation, high-voltage arc resistance, corrosion resistance, and electronic heat dissipation insulation. It is compatible with all mainstream insulating resin systems, including epoxy, silicone, fluorocarbon, polyimide, PTFE-modified, and polyurethane, and is widely used in power electrical equipment, high-temperature equipment, new energy, industrial control electronics, and chemical corrosion protection and insulation applications.

Core performance advantages of green silicon carbide compatible insulating coatings

1. Stable electrical insulation, arc resistance, and creepage resistance: High-purity green silicon carbide has extremely high resistivity at both room and high temperatures and is inherently non-conductive. When infiltrated into the coating, it enhances resistance to arc erosion and surface leakage, and is less prone to breakdown and carbonization under high voltage. Ordinary calcium carbonate and mica are easily conductive at high temperatures and are easily burned through by arcs, while green silicon carbide can withstand high-voltage arc impacts for extended periods. It also possesses non-linear conductivity characteristics, uniformly dispersing the electric field under high-voltage conditions and preventing localized electric field concentration breakdown. It is widely used in high-voltage anti-corona insulation coatings.

2.High-temperature resistant insulation, with insulation that does not fail at high temperatures. Green silicon carbide can withstand temperatures above 1600℃ for extended periods without softening, decomposing, or releasing ions to conduct electricity. A dense SiO2 protective film forms on the high-temperature surface, isolating oxygen and corrosive gases and ensuring stable insulation performance under high-temperature conditions. Mica and ordinary fillers experience significant insulation degradation above 300℃. Green silicon carbide is suitable for insulation in high-temperature motors, kilns, and pipelines.

3. Dual Properties of Insulation and High Thermal Conductivity: Conventional insulating fillers generally have poor thermal insulation and conductivity, which can easily lead to heat buildup and breakdown in electronic components; Green silicon carbide has a thermal conductivity of 120~150W/(m.K), which is 10~20 times that of ordinary insulating fillers (mica, talc), ensuring electrical insulation without leakage and rapid heat dissipation, solving the problem of overheating and stuffiness in insulating coatings, and making it suitable for insulating and heat dissipating coatings for power devices.

4. Resistant to acids, alkalis, and solvents, the insulation layer is not easily corroded and fails. It is resistant to strong acids, strong alkalis, organic solvents, oil stains, and salt spray at room temperature. In chemical environments, it will not be swollen or dissolved by the medium, causing leakage through pores in the insulation layer. Many insulation coating failures are essentially due to the corrosion of fillers, resulting in micropores. The chemical inertness of green silicon carbide eliminates this problem.

5. Mechanical reinforcement enhances the insulation layer’s crack resistance, wear resistance, and adhesion. With a Mohs hardness of 9.4~9.5, the hardness, impact resistance, and wear resistance of the coating film are significantly improved after filling. The extremely low coefficient of thermal expansion prevents cracking and peeling during thermal cycles, avoiding leakage caused by cracks. The particles form a physical anchor, improving the adhesion of the coating film to the metal substrate and preventing coating peeling and leakage.

6. Excellent compatibility with coating application: Acid-washed and graded green silicon carbide micro powder has low oil absorption, good dispersion and suspension, and is not prone to sedimentation and agglomeration; it can be modified with silane coupling agents and has good compatibility with various insulating resins; it can filler replace part of the resin, reduce VOC, control costs, and at the same time adjust the coating leveling, anti-sagging, and matte effect.

Zhengzhou haixu abrasives co.,ltd,manufacturer of silicon carbide from China for more than 20years.

The sizes of microgrits we produce as follows:

FEPA Standard

JIS Standard