SILICON CARBIDE BRICKS

Choose SiC where abrasion, erosion, thermal cycling or high heat-transfer rates dominate. Common cases: aluminium melting and holding furnaces (non-wetting), zinc smelter retorts, waste incinerator hearths, blast furnace bosh, kiln burner blocks, and recuperator tubes. SiC has 5–10× the thermal conductivity of high alumina, ideal where heat must move through the lining, problematic where insulation is needed.

Continuous service to 1650°C in oxidising atmospheres. In reducing or inert atmospheres, SiC tolerates 1700°C+. Above 1300°C in oxidising atmospheres SiC slowly forms a passivating SiO₂ layer that limits further oxidation but reduces thermal conductivity over time. For melting iron and steel direct contact, SiC is generally avoided due to dissolution into the melt.

Excellent. SiC is non-wetting to molten aluminium and resists corundum growth and metal penetration. It handles cycling between fill, hold and tap without spalling. The standard duty is the lower belly and ramps of melting furnaces; for the metal contact wall, Si₃N₄-bonded SiC is preferred over clay-bonded SiC for longer life.

Three common bonds: oxide-bonded (clay or alumina, lowest cost, used in non-critical zones), Si₃N₄-bonded (silicon nitride, premium aluminium duty), and direct-sintered or recrystallised SiC (highest performance, kiln furniture and special parts). The bond choice drives both price and service life, typically a 2–4× span across the range.

Standard SiC shapes are stocked from 1 MT upwards. Special shapes, recrystallised SiC parts and Si₃N₄-bonded grades are usually made-to-order with a 4–8 week lead time and a minimum order of 1–2 MT depending on the supplier. We can quote both stocked grades from CUMI and made-to-order grades from TRL Krosaki and Calderys.

Yes, typically 3–6× the price per tonne of HA-90, depending on bond and SiC content. The economic case is built on longer life, lower energy loss and higher productivity, not initial cost. For an aluminium melter the payback on Si₃N₄-bonded SiC over alumina-silicate is usually 9–18 months in extra metal yield and reduced relining frequency.