Introduction

Silicon Carbide (SiC) are produced by Tech Ceramic in various variants depending on the application, but they are all characterized by the typical properties of silicon carbide, such as:

  • Very high hardness,
  • Corrosion resistance at high temperatures
  • High wear resistance
  • High strength at high temperatures
  • Oxidation resistance
  • Good thermal shock resistance
  • Low thermal expansion
  • Very high thermal conductivity

Open Porous SiC

  • Tecsic-RC: Recrystallized Silicon Carbide (RSiC)
  • Tecsic-N: Nitride Bonded Silicon Carbide (NSiC)

Dense SiC

  • Tecsic-R: Reaction Bonded Silicon Carbide (SiSiC)
  • Tecsic-P: Pressureless Sintered Silicon Carbide (SSiC)
  • Tecsic-BN: Pressureless Sintered SiC and Boron Nitride Composite (SSiC-BN)
  • Tecsic-CG: Pressureless Sintered SiC and Carbon Graphite Composite (SSiC-CG)
  • Tecsic-I: Hot Isostatically Pressed Silicon Carbide (HIPSiC)

Products Made From Silicon Carbide

Recrystallized silicon carbide (RSIC) is a pure silicon carbide material with about 11 to 15% open porosity. This ceramic is fired at very high temperatures of 2,300 to 2,500 ° C, whereby a mixture of the finest and coarse powder converts without shrinkage to a compact SiC matrix. Due to its open porosity, the RSiC has lower strengths than the dense silicon carbide ceramics.

  • Kiln Furniture (Beam, Roller, Setter Plate, Kiln Shelf)
  • TecMemTM Membranes (Silicon Carbide)
  • Membranes Elements (With Stainless Steel Housing)

Nitride Bonded Silicon Carbide (NSiC) is a porous material, with 10 to 15% porosity and 1 to 5% of open porosity. The silicon nitride matrix causes components made from NSiC to be less wetted by non-ferrous molten metals. Suitable applications such as pump parts, thermocouple protection tubes, and rotary degassers.

Reaction-bound silicon carbide (SiSiC) consists of about 85 to 94% SiC and correspondingly 15 to 6% of metallic silicon. SiSiC has virtually no residual porosity. This is achieved by infiltrating silicon carbide and carbon with metallic silicon. The reaction between liquid silicon and the carbon leads to a SiC bond matrix, the remaining pore space is filled up with metallic silicon. The advantage of this production technique is that, in contrast to the powder sintering techniques, the components do not undergo shrinkage during the siliconizing process. Therefore, extremely large components with precise dimensions can be produced. The range of application of the SiSiC is limited to approx. 1380℃ due to the melting point of the metallic silicon.

Pressureless sintered silicon carbide (SSiC) is made of high-purity and ultra-fine silicon carbide powder, and a small amount of sintering aid, such as boron, carbon, etc., is sintered in an inert gas or vacuum atmosphere at atmospheric pressure at a high temperature of 1950~2100 °C. The resulting article is almost completely dense and has a ceramic material with excellent mechanical properties.

Hot isostatically pressed silicon carbide (HIPSiC) has even higher mechanical properties compared to the non-pressure sintered SSiC as the components become almost non-porous due to the additional pressures up to approx. 2000 bar during the sintering process. The isostatic (HIP) pressing technique restricts the components to be manufactured to relatively simple or small geometries and means additional expense compared to pressureless sintering.HIPSiC is therefore used exclusively in areas of extreme stress.