Pressureless Sintered Silicon Carbide (SSiC) Refractory Products

SiC refractory products are high-performance special ceramic refractory parts made from pressureless sintered silicon carbide (SSiC) as the base material. They include two material grades, Benecust BP and Benecust BE, with properties controlled by different grain sizes. Silicon carbide kiln furniture is the core category of this series, including silicon carbide kiln shelves, setter plates, flame baffles, support parts, saggar components, and custom kiln furniture structural parts. They are used for carrying, supporting, isolating, and sintering workpieces in high-temperature kilns. They offer high high-temperature strength, good thermal conductivity, thermal shock resistance, wear resistance, and corrosion resistance, suitable for ceramic, powder metallurgy, lithium battery material, electronic material, and refractory material sintering applications.

The products are high-temperature resistant, thermal shock resistant, highly thermally conductive, hard, and wear-resistant, with broad-spectrum resistance to strong acids and alkalis. The biggest difference from graphite products: silicon carbide can be used stably in air, non-vacuum, and non-protective atmosphere high-temperature environments for long periods, and will not suffer high-temperature oxidation loss like graphite. It is a preferred material for harsh high-temperature corrosive conditions. Custom shapes and sizes can be produced from drawings, with single-piece and small-batch orders supported.

Material Performance

We provide two types of pressureless sintered silicon carbide substrates, with differentiated performance achieved by adjusting grain fineness.

1. Benecust BP (Fine-Grain Pressureless Sintered Silicon Carbide)

Silicon carbide content >98.5 wt%, average grain size 4–10 μm; density >3.14 kg/dm³, apparent porosity <0.5%; room-temperature three-point flexural strength 450 MPa, compressive strength 3900 MPa, elastic modulus 420 GPa, Vickers hardness 28 GPa, thermal conductivity 160 W/(m·K), maximum service temperature 1700°C.
Suitable for: high-pressure, strong scouring, high-precision, and high-wear conditions. It has higher density and better strength, hardness, and thermal conductivity.

2. Benecust BE (Coarse-Grain Pressureless Sintered Silicon Carbide)

Silicon carbide content >98 wt%, average grain size 4–50 μm; density >3.05 kg/dm³, apparent porosity <3.0%; room-temperature three-point flexural strength 380 MPa, compressive strength 3500 MPa, elastic modulus 380 GPa, Vickers hardness 22 GPa, thermal conductivity 140 W/(m·K), maximum service temperature 1700°C.
Suitable for: balancing thermal shock resistance and cost, suitable for conventional high-temperature kilns and chemical corrosion conditions.

Comparison of Silicon Carbide Sintering Processes

Selection points: Pressureless sintered silicon carbide has significantly better high-temperature strength retention than other sintering systems. Its strength does not decrease but increases at 1600°C, and it can be used up to 1700°C in air. Reaction-bonded silicon carbide is limited by free silicon, with a maximum service temperature of only 1380°C. Recrystallized silicon carbide has high porosity and low room-temperature strength.

Advantages of SiC Refractory Products

Compared with ordinary refractories, oxide ceramics, and graphite products, pressureless sintered silicon carbide refractory products offer more comprehensive high-temperature stability and working condition adaptability:

1. Can be used in air and non-protective atmospheres long-term
   Unlike graphite materials, silicon carbide can work stably in high-temperature air environments without vacuum or protective atmosphere, avoiding graphite burning, spalling, and life decay in oxidizing atmospheres. It is suitable for continuous kilns, air-atmosphere sintering, and heat treatment conditions.

2. High high-temperature strength retention
   Pressureless sintered silicon carbide still maintains high elastic modulus and flexural strength above 1200°C. Benecust BE can reach a maximum service temperature of 1700°C in air at 1600°C, far higher than the long-term service temperature of reaction-bonded silicon carbide.

3. Excellent thermal shock resistance
   Silicon carbide has high thermal conductivity and a low coefficient of thermal expansion. It can withstand frequent thermal cycles and rapid heating and cooling, reducing the risk of cracking, deformation, and failure of kiln components due to thermal stress.

4. High thermal conductivity and stable high-temperature creep resistance
   High thermal conductivity allows silicon carbide products to distribute temperature more evenly in kiln and heat exchange conditions, helping reduce local overheating and thermal deformation. High-temperature creep is small, and dimensional stability under long-term load-bearing conditions is better.

5. Strong comprehensive wear, corrosion, and scouring resistance
   Silicon carbide has high hardness, high wear resistance, and broad-spectrum corrosion resistance. It can withstand strong acids, strong alkalis, molten media, particle scouring, and high-temperature flue gas corrosion. It is suitable for nozzles, protection tubes, molds, kiln furniture, and other vulnerable parts.

6. Dense material structure and longer life
   Benecust BP fine-grain structure has higher density, suitable for high-strength, high-wear, and high-precision conditions. Benecust BE coarse-grain structure has more outstanding thermal shock resistance, suitable for high-temperature kilns and complex thermal cycling environments. Both are superior to ordinary refractories and recrystallized silicon carbide under strong corrosion and strong scouring conditions.

7. High degree of customizability
   Supports machining of different shapes, sizes, hole positions, thicknesses, and surface precision according to drawings. Strength, thermal conductivity, thermal shock resistance, and cost options can be selected according to working conditions, suitable from single-piece trial production to batch production.

Product Series

1. Silicon Carbide Heating Element (Silicon Carbide Heating Rod)
silicon carbide heating rod / silicon carbide heating element / silicon carbide heating elements / silicon carbide heater
Pressureless sintered silicon carbide heating elements, stable in high-temperature air, oxidation-resistant, uniform heating, up to 1700°C. Integrated silicon carbide heating assembly, relying on the high thermal conductivity, high-temperature resistance, and corrosion resistance of the silicon carbide substrate. Customizable structure, fast thermal response, uniform furnace temperature field. Suitable for muffle furnaces, sintering kilns, heat treatment furnaces, precious metal melting furnaces, and various high-temperature process equipment.

2. Silicon Carbide Tube
silicon carbide tubing
Dense pressureless sintered silicon carbide tubes, thermal shock resistant, resistant to strong acid and alkali corrosion, no deformation at high temperature. Used as chemical heat exchange tubes, kiln radiant tubes, and corrosive fluid transport pipes in fine chemicals, hydrometallurgy, and high-temperature kilns.

3. Silicon Carbide Nozzle
silicon carbide nozzle
High-hardness wear-resistant silicon carbide nozzles, resistant to high-speed particle scouring, high temperature, and chemical corrosion. Used for powder sandblasting, flue gas washing and spraying, and chemical medium spraying, greatly extending the service life of wear parts.

4. Silicon Carbide Plate / Silicon Carbide Kiln Shelf
silicon carbide plate / silicon carbide plates / sic plate / silicon carbide kiln shelf / silicon carbide kiln shelves
Silicon carbide firing shelves and refractory partitions, low high-temperature creep, not easy to crack under repeated thermal cycling. Used in ceramic sintering, powder metallurgy, and lithium battery material calcination kilns for carrying workpieces.

5. Silicon Carbide Protection Tube
silicon carbide protection tube
Special silicon carbide protection tubes for thermocouple temperature measuring elements, isolating high-temperature flue gas, corrosive gases, and molten media, protecting internal sensors, and ensuring stable temperature measurement under high-temperature corrosive conditions.

6. Silicon Carbide Mold
silicon carbide mold
Silicon carbide molds for non-ferrous metal melting, precious metal melting, glass forming, and high-temperature press forming. They feature high-temperature resistance, thermal shock resistance, resistance to molten medium erosion, and good surface stability. They can reduce workpiece sticking, deformation, and defects, improving forming quality and mold life.

Applications

Powder metallurgy, electronic ceramics, lithium battery cathode material calcination, precious metal smelting, fine chemicals, heat treatment, glass industry, laboratory high-temperature equipment, environmental flue gas treatment, refractory material sintering, ceramic kilns, metal melting, and glass forming.

Core Advantages

1. Usable in air: Compared with graphite products, no vacuum/protective atmosphere is needed, and it will not oxidize or burn under atmospheric high-temperature conditions, greatly simplifying equipment configuration.

2. Selectable material grades: Benecust BP fine-grain / Benecust BE coarse-grain pressureless sintered silicon carbide, matching wear resistance, high strength, and thermal shock resistance requirements.

3. Excellent high-temperature performance: Pressureless sintered silicon carbide has high high-temperature strength retention and can still serve stably at 1700°C in air.

4. Broad-spectrum corrosion resistance: Resistant to nitric acid, concentrated sulfuric acid, strong alkalis, various salt solutions, and organic corrosive media.

5. High thermal conductivity and thermal shock resistance: Not easy to break under thermal cycling; high hardness and wear resistance, resistant to particle scouring.

6. Rich product types: Covering heating elements, tubes, nozzles, kiln shelves, protection tubes, molds, and silicon carbide kiln furniture.

7. Drawing-based custom machining supported: Non-standard sizes, single-piece and small-batch orders can be produced.