SIC silicon carbide ceramics

Reaction Bonded Silicon Carbide – Tiles, Liners, Bricks, Cylinders, Hexmats, Mosaicmats, Rubber Mats

Reaction bonded silicon carbide (RBSiC) is a two‑phase ceramic composite. It is made by infiltrating molten silicon into a porous preform that contains silicon carbide powder and carbon. The silicon reacts with carbon to form additional silicon carbide, and the remaining metallic silicon fills the pore network. The finished material contains roughly 85–94% SiC and 6–15% free silicon, with open porosity below 0.1%.

This combination gives RBSiC a set of properties that are useful in industrial wear applications. Hardness is about Mohs 9.5. Vickers hardness ranges from 2000 to 3500 HV depending on the specific grade and manufacturing conditions. The material maintains flexural strength above 250 MPa up to 1200°C. Thermal expansion is about 4.5×10⁻⁶/K, and thermal conductivity at 1200°C is approximately 45 W/m·K. Chemically, it resists most acids and alkalis. The free silicon phase is attacked by hydrofluoric acid and by strong alkalis at high temperatures; for most mining, coal, and cement applications this is not a limiting factor.

Tecera supplies RBSiC in multiple forms. Tiles and bricks are the most common – square or rectangular tiles from 6 mm to 25 mm thick, and interlocking bricks for ball mill linings up to 110 mm thick. Cylinders are used as pipe liners or vortex finders. Hexmats are flexible mats of hexagonal ceramic tiles mounted on a fiber mesh; mosaicmats are similar but with small square tiles. Rubber mats combine RBSiC tiles vulcanized into a rubber sheet for impact absorption. Custom shapes are manufactured to customer drawings.

What distinguishes RBSiC from other wear materials

Compared to 95% alumina, RBSiC is harder – Mohs 9.5 versus 9 – and has roughly 50% higher fracture toughness. In practice, the wear rate difference depends on the abrasive material and velocity. For quartz (Mohs 7) in high‑velocity slurry, RBSiC typically wears five to ten times slower than 95% alumina. This is not a universal guarantee; it varies with ore type, particle shape, and operating conditions. But the trend is consistent across multiple industrial installations.

Compared to rubber or polyurethane, RBSiC handles sharp, angular particles without tearing or swelling. Rubber liners in coal prep cyclones often fail after 12–18 months due to particle impact and chemical attack from acidic process water. RBSiC liners in the same service have been documented to last five years or more.

Compared to steel, RBSiC is much harder. Steel is about Mohs 5–6, depending on alloy and heat treatment. Quartz at Mohs 7 is harder than steel, so steel wears rapidly when conveying quartz‑rich material. A steel elbow in a fly ash line may wear through in six months. An RBSiC elbow can run for several years.

Manufacturing and quality control

The production process begins with high‑purity SiC powder and a controlled carbon source. The powder blend is formed into the desired shape. For simple geometries such as flat tiles, uniaxial dry pressing is used. For more complex shapes – cone sections, cylinders, and thick bricks – cold isostatic pressing is preferred because it applies uniform pressure from all directions. Uniform density is important; density gradients lead to localized wear and premature failure.

After forming, the green body is dried slowly. Rapid drying causes micro‑cracks that are not visible at the time but grow under service conditions. The dried part is then placed in a vacuum furnace and heated above 1414°C. Molten silicon infiltrates the porous preform by capillary action. The exothermic reaction between silicon and carbon produces additional SiC, which bonds the original SiC grains. Any remaining pores are filled with metallic silicon. The entire reaction occurs with almost no dimensional change – typically less than 0.1% linear shrinkage. This near‑net‑shape capability is a key advantage of RBSiC over sintered SiC (SSiC), which shrinks 15–20% and requires extensive post‑machining.

After reaction bonding, the parts are cooled under controlled conditions to avoid thermal shock. Critical surfaces are precision‑ground where tolerances below ±0.5 mm are required. Quality checks include measurement of bulk density (Archimedes method per ASTM C20), open porosity (water absorption test), flexural strength (3‑point bend per ASTM C1161), and Vickers hardness (ASTM C1327). Each batch is also visually inspected for chips, cracks, and dimensional variation. Parts that fail any of these checks are rejected. In a typical year, about 2–3% of production is rejected before shipment.

Technical Specifications

The following values are typical for Tecera's RBSiC. Batch certificates are available.

Available forms:

Tiles: square or rectangular, thickness 6–25 mm, typical sizes 150×50 mm, 150×100 mm, 100×100 mm

Bricks: trapezoid or interlocking, thickness 40–110 mm, for ball mill linings

Cylinders: custom diameters, up to 500 mm length

Hexmats: hexagonal tiles on fiber mesh, 500×500 mm or 1000×1000 mm

Mosaicmats: small square tiles on mesh, 300×300 mm or 500×500 mm

Rubber mats: RBSiC tiles vulcanized to rubber, up to 1000×2000 mm

Cone sections: custom per drawing

Custom shapes: per customer drawing

Common forms and dimensions

Tiles (square or rectangular): thickness 6, 8, 10, 12, 15, 20, 25 mm. Standard tile sizes are 150×50 mm, 150×100 mm, and 100×100 mm. Other sizes available.

Bricks (trapezoid interlocking): thickness 40, 50, 60, 70, 77, 90, 110 mm. Length 150 mm, top width 50 mm, bottom width 45 mm. Half‑bricks also available.

Cylinders: custom outer diameter and length, typically up to 500 mm long. Used as pipe liners or vortex finders.

Hexmats: hexagonal tiles (typically 20–30 mm across flats) mounted on a flexible fiber mesh. Mat size 500×500 mm or 1000×1000 mm. Tile thickness 6–12 mm.

Mosaicmats: small square tiles (typically 15–25 mm) on mesh. Mat size 300×300 mm or 500×500 mm. Tile thickness 6–10 mm.

Rubber mats: RBSiC tiles vulcanized into a natural rubber or SBR sheet. Total thickness 12–30 mm (ceramic 6–12 mm, rubber 6–18 mm). Mat size up to 1000×2000 mm.

Cone sections and other custom shapes: manufactured to customer drawings. We accept DWG, PDF, and STEP files.

Where RBSiC products are installed

Hydrocyclones in mining and mineral processing. The cone, spigot, vortex finder, and feed inlet are all lined with RBSiC tiles or one‑piece cast cones. In copper concentrators processing high‑silica ore, RBSiC cones have been known to last four to five years, whereas 95% alumina cones typically require replacement after 8–14 months.

Coal preparation cyclones – heavy medium and classifying. Coal particles are sharp; magnetite slurry is abrasive; process water is often acidic. RBSiC liners are used in coal prep plants in the United States, Australia, China, and India. A plant in West Virginia reported that RBSiC cyclones remained in service for five years, compared to 14–18 months for rubber‑lined cyclones.

Fly ash handling in coal‑fired power plants. Fly ash is hard (containing quartz and mullite) and is conveyed at high velocity. Steel elbows wear through in 6–12 months. RBSiC elbows have been used in power plants for over a decade. A plant in Ohio installed RBSiC elbows in their ash handling system and found them still intact after eight years.

Sinter plant chutes in steel mills. Sinter is hot – typically 300–500°C – and abrasive. Alumina tiles crack from thermal cycling. Rubber burns. RBSiC handles both the temperature and the abrasion. A steel mill in China replaced their sinter chute liners every 8 months with alumina. After switching to RBSiC, the same chute ran for over three years before needing attention.

Cement plant clinker chutes. Clinker is hard and can be as hot as 400°C at the cooler discharge. Steel chutes wear through quickly. RBSiC liners are used in cement plants in Brazil, Europe, and Southeast Asia. A plant in Brazil reported that an RBSiC‑lined clinker chute lasted 30 months; the previous steel chute was replaced every 6 months.

Sand and aggregate processing. Silica sand is Mohs 7, close to the hardness of alumina. Rubber and polyurethane liners in sand cyclones wear out quickly. RBSiC liners typically last 5–10 times longer. A sand plant in Texas that switched to RBSiC cyclones reduced their annual maintenance downtime from 12 days to 2 days.

Installation methods

Standard tiles and bricks are bonded to the steel substrate with a two‑part epoxy adhesive. The steel surface must be cleaned of rust, oil, and loose scale. A wire brush or grinder is sufficient. The epoxy is applied to the back of each tile, and the tile is pressed into place. The adhesive cures at room temperature; full bond strength is reached after 24 hours.

Hexmats and mosaicmats are installed using the same epoxy. The flexible mat conforms to curved surfaces, which reduces gaps that would otherwise occur with rigid tiles. The mat is pressed into the adhesive and held in place with temporary supports until the epoxy sets.

Rubber mats can be installed with epoxy or with mechanical fasteners. For epoxy installation, the back of the rubber mat is cleaned and a neoprene‑based contact adhesive is applied. For mechanical fixation, countersunk bolts are used; the bolt heads sit below the ceramic surface. Mechanical attachment is preferred where impact is severe or where the steel surface is difficult to clean.

Cone sections and other custom shapes are typically installed with epoxy, but can also be bolted if the design includes mounting holes.

Limitations and considerations

RBSiC is not suitable for every application. It is more expensive than alumina, and much more expensive than steel or rubber. The economic case depends on the wear rate and the cost of downtime. For a plant that processes high volumes of hard, abrasive material, the longer life of RBSiC often justifies the higher upfront cost. For a plant with low throughput or soft material, alumina or steel may be more economical.

RBSiC is also brittle. While its fracture toughness (4.0–4.5 MPa·m¹/²) is better than that of 95% alumina (3.5–4.0), it is still a ceramic. Heavy impact – such as large rocks dropping from height – can crack RBSiC tiles. For such applications, rubber mats or steel‑backed composites are more appropriate.

The free silicon phase limits chemical compatibility. RBSiC should not be used with hydrofluoric acid or with strong alkalis at temperatures above about 80°C. For most mining, coal, cement, and power plant applications, this is not an issue. For chemical plants handling these specific media, alternative materials such as sintered SiC or silicon nitride should be considered.

Ordering information

To request a quote, please provide the following:

• Component type (tile, brick, cylinder, hexmat, mosaicmat, rubber mat, or custom)
• Dimensions (length, width, thickness; or a drawing)
• For custom shapes: drawing in DWG, PDF, or STEP format
• Operating conditions: material being handled, particle size, temperature, pH, velocity
• Estimated annual quantity

We respond to quote requests within two business days. Bulk pricing is available for wholesale buyers. Free samples for destructive testing are available. Lead time for standard shapes is 2–4 weeks; custom shapes require 4–6 weeks. Shipping is available worldwide with export‑grade packaging.

Hot Tags: SIC silicon carbide ceramics, China SIC silicon carbide ceramics manufacturers, suppliers, factory, refractory ceramic, reaction bonded silicon carbide