By TRUNNANO | 24 October 2023 | 0 Comments
Production technology and defects of silicon carbide ceramics
Silicon carbide ceramics have low density, high stiffness, low thermal expansion, and dimensional stability. They are widely used in aerospace, petrochemicals, integrated circuits, and other fields. Silicon carbide sintering densification is difficult due to its high covalent bond characteristics and very low diffusion coefficient, so a variety of sintering preparation technologies have been developed.
At present, the mature industrial production of silicon carbide ceramic materials is the main way of reaction sintering, atmospheric pressure sintering, recrystallization sintering, hot pressing sintering, and hot isostatic pressing sintering. In addition, new sintering technologies such as discharge plasma sintering, flash firing, and oscillating pressure sintering are also being studied and paid attention to. In industrial production, reaction sintering, atmospheric pressure sintering, and recrystallization sintering are three kinds of silicon carbide ceramic material preparation methods that have their own unique product shrinkage rate is very small, high degree of densification, suitable for the preparation of large-size complex shape structural parts, reaction sintering silicon carbide is mostly used in high-temperature kiln, flame nozzle, heat exchanger, optical mirror and other aspects. The advantage of atmospheric pressure sintering is that the production cost is low, there is no limit to the shape and size of the product, the prepared product has high density, uniform microstructure, and excellent comprehensive performance of the material, so it is more suitable for the preparation of precision structural parts, such as seals in various mechanical pumps, plain bearings and bulletproof armor, optical mirrors, semiconductor wafer fixtures and so on. Recrystallized silicon carbide has a pure crystalline phase, no impurities, high porosity, excellent thermal conductivity, and thermal shock resistance. It is an ideal candidate for high-temperature kiln wares, heat exchangers, or combustion nozzles.
However, the hardness and brittleness of silicon carbide ceramics are high, which makes it easy to produce defects in the processing process, and silicon carbide ceramic components with complex geometric shapes are often difficult to manufacture by traditional processing technology, which restricts the application of complex structure silicon carbide ceramics to a large extent.
The method of high-temperature fusion deposition combined with reaction sintering for the preparation of SiC ceramics uses high-temperature in-situ interface modification powder and low-temperature stress release to prepare a high plastic printing body. It obtains a high plastic printing body with a low melting point and high boiling point, and the material solid content exceeds 60vol%. After that, the 3D printer UPS-556 was used to carry out high-density lamination printing on the plastic body. The equivalent carbon density of the printed ceramic sample after degradation could be precisely adjusted to 0.80 g·cm-3. At the same time, the topological optimization design of the ceramic printing path could be carried out to form a tree-shaped multistage pore in the sample. The final ceramic sample without CVI or PIP treatment can achieve high-efficiency penetration and material densification with low residual silicon/carbon after direct reaction ionizing sintering. The density of SiC ceramic can reach 3.05±0.02 g·cm-3, the three-point bending strength is 310.41±39.32 MPa, and the elastic modulus is 346.35±22.80 GPa. The mechanical properties of SiC ceramics are close to those of reaction-sintered sic ceramics prepared by traditional methods.
High-quality silicon carbide powder supplier
TRUNNANO is a globally recognized manufacturer and supplier of compounds with more than 12 years of expertise in the highest quality nanomaterials and other chemicals. The company develops a variety of powder materials and chemicals. Provide OEM service. If you need silicon carbide powder, please feel free to contact us. You can click on the product to contact us.
However, the hardness and brittleness of silicon carbide ceramics are high, which makes it easy to produce defects in the processing process, and silicon carbide ceramic components with complex geometric shapes are often difficult to manufacture by traditional processing technology, which restricts the application of complex structure silicon carbide ceramics to a large extent.
The method of high-temperature fusion deposition combined with reaction sintering for the preparation of SiC ceramics uses high-temperature in-situ interface modification powder and low-temperature stress release to prepare a high plastic printing body. It obtains a high plastic printing body with a low melting point and high boiling point, and the material solid content exceeds 60vol%. After that, the 3D printer UPS-556 was used to carry out high-density lamination printing on the plastic body. The equivalent carbon density of the printed ceramic sample after degradation could be precisely adjusted to 0.80 g·cm-3. At the same time, the topological optimization design of the ceramic printing path could be carried out to form a tree-shaped multistage pore in the sample. The final ceramic sample without CVI or PIP treatment can achieve high-efficiency penetration and material densification with low residual silicon/carbon after direct reaction ionizing sintering. The density of SiC ceramic can reach 3.05±0.02 g·cm-3, the three-point bending strength is 310.41±39.32 MPa, and the elastic modulus is 346.35±22.80 GPa. The mechanical properties of SiC ceramics are close to those of reaction-sintered sic ceramics prepared by traditional methods.
High-quality silicon carbide powder supplier
TRUNNANO is a globally recognized manufacturer and supplier of compounds with more than 12 years of expertise in the highest quality nanomaterials and other chemicals. The company develops a variety of powder materials and chemicals. Provide OEM service. If you need silicon carbide powder, please feel free to contact us. You can click on the product to contact us.
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