Classification, Characteristics, and Applications of Silicon Carbide Abrasives

Silicon carbide abrasives, as an indispensable key material in modern industry, have become an important support for many sectors due to their unique physical and chemical properties and wide range of applications. From basic abrasive tool manufacturing to high-precision material processing, silicon carbide abrasives demonstrate irreplaceable value. This article provides a detailed analysis to help you understand the two main categories of silicon carbide abrasives—black silicon carbide and green silicon carbide—including their formation conditions, notable characteristics, and broad application areas, aiming to offer valuable references and insights for related industries.

1. Classification and Formation Conditions of Silicon Carbide Abrasives

Silicon carbide abrasives are mainly divided into two categories: black silicon carbide and green silicon carbide, each with distinct formation conditions.

Formation Conditions of Black Silicon Carbide

• Raw materials:

  • Quartz sand: Provides silicon, one of the basic components of silicon carbide.

  • Coke (or other carbon-containing materials): Such as coal tar, petroleum coke, sawdust, bamboo charcoal, etc., providing carbon, which reacts with silicon at high temperatures to form silicon carbide.

• Process:

  • High-temperature smelting in a resistance furnace: Raw materials are placed in a resistance furnace and heated by electric current to high temperatures (usually above 2000°C), allowing silicon and carbon to react and form silicon carbide.

  • Reaction control: Strict control of temperature, reaction time, and atmosphere during smelting is required to ensure product quality and performance.

• Other conditions:

  • Furnace structure: The furnace should be reasonably designed to ensure uniform heating of the raw materials and improve product uniformity and quality.

  • Cooling method: After smelting, appropriate cooling methods are used to allow the product to cool and solidify quickly, avoiding cracks or deformation.

Formation Conditions of Green Silicon Carbide

• Raw materials:

  • Petroleum coke: Provides carbon, one of the components of silicon carbide.

  • High-quality silica: Provides silicon, which reacts with carbon at high temperatures to form silicon carbide.

  • Salt (sodium chloride): Added as an additive to promote the formation of silicon carbide and influence the color and performance of the product.

• Process:

  • High-temperature smelting in a resistance furnace: Similar to black silicon carbide, raw materials are placed in a resistance furnace and heated by electric current to high temperatures (usually around 2200°C), enabling the reaction between silicon and carbon.

  • Reaction control: Strict control of temperature, reaction time, atmosphere, and the amount and method of salt addition is needed to ensure product quality and performance.

• Other conditions:

  • Furnace structure: A well-designed furnace structure is also required to ensure uniform heating and improve product quality.

  • Cooling method: Appropriate cooling methods are used after smelting to quickly cool and solidify the product, avoiding cracks or deformation.

  • Raw material purity: Green silicon carbide requires higher raw material purity, as impurities affect color and performance. Therefore, strict screening and purification of raw materials are needed before smelting.

2. Characteristics of Black and Green Silicon Carbide

• Black Silicon Carbide

  • Hardness and wear resistance: Second only to diamond and corundum, with remarkable microhardness and strong wear resistance, suitable for maintaining sharpness over long periods.

  • High-temperature resistance and oxidation resistance: Maintains stable physical and chemical properties in high-temperature environments and is not easily oxidized.

  • Toughness: Higher toughness compared to green silicon carbide, capable of withstanding greater impact loads, suitable for grinding operations with larger impacts.

• Green Silicon Carbide

  • Purity and self-sharpening: High purity, easily fractured to form new cutting edges, improving grinding efficiency.

  • Thermal conductivity: Excellent thermal conductivity, quickly dissipating heat generated during grinding to prevent workpiece overheating.

  • Semiconductor properties: Possesses semiconductor characteristics, playing an important role in the cutting and grinding of semiconductor materials.

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3. Application Areas of Black and Green Silicon Carbide

• Black Silicon Carbide

  • Abrasive tool manufacturing: Used to make resin abrasives, ceramic abrasives, coated abrasives, etc.

  • Material processing: Suitable for processing materials with low tensile strength, such as glass, ceramics, stone, refractory materials, cast iron, and non-ferrous metals.

  • Advanced refractory materials: Used to manufacture advanced refractory products with thermal shock resistance, small volume, light weight, and high strength.

  • Other applications: Used as a deoxidizer and in the manufacture of silicon carbide heating elements.

• Green Silicon Carbide

  • Hard material processing: Mainly used for processing hard alloys, titanium alloys, and optical glass, as well as for honing cylinder liners and precision grinding of high-speed steel tools.

  • High-precision processing: Used in high-precision fields such as honing and ultra-fine grinding.

  • Semiconductor materials: Plays an important role in the cutting and grinding of semiconductor materials.

  • Other applications: Used to make high-temperature silicon carbide heating elements and as a substrate for far-infrared sources.

Conclusion

In summary, black and green silicon carbide, as the two main categories of silicon carbide abrasives, each show unique advantages in terms of formation conditions, notable characteristics, and broad application areas. Black silicon carbide, with its high hardness, high-temperature resistance, and good toughness, plays an important role in abrasive tool manufacturing and material processing. Green silicon carbide, with its high purity, excellent self-sharpening, and superior thermal conductivity, is crucial in hard material processing, high-precision machining, and semiconductor material cutting and grinding. As technology advances and industry continues to upgrade, the application fields of silicon carbide abrasives will become even broader, and their importance in industrial manufacturing will only increase. Therefore, in-depth research into the properties and applications of silicon carbide abrasives is of great significance for promoting the development of related industries.