This material is one of the most abrasion resistant materials after diamond and boron nitride and is fifty percent harder than tungsten carbide. This makes it ideal for use as wear parts primarily for pump bearings and seal faces at high pressures and in hostile environments. It exhibits an amazing resistance to thermal shock and is surprisingly light in weight.

There exist two main types of fully dense sintered Silicon Carbide both having very similar properties. Reaction Bonded SiC such as ‘Refel’ and Sintered SiC such as Hexoloy or Ekasic. For most applications we supply accurately machined and polished parts in Sintered Silicon Carbide, unless requested otherwise, as it has a very low free silicon content.

Occasionally we are also involved in machining porous crystalline Silicon Carbide blocks into various geometric shapes.

Main Characteristics of Sintered Silicon Carbide

  • High corrosion and wear resistance
  • High compressive strength
  • High no load operating temperature (>1900°C)
  • Excellent thermal shock resistance
  • Low thermal expansion
  • Highly Thermally conductive
  • Extremely Hard (2800Kg/cm³ on the Knoop scale)
  • Low density (±3.0gm/cm³)
  • Fully impervious

Parameters

We supply precision ground and/or polished parts in this material mostly within the following size limits.

Rods: Up to Ø50mm x 300mm long
Discs: Up to Ø500mm x 25mm thick
Plates: Up to 1000mm x 400mm x 50mm thick
Tubes & Rings: Up to 400mm OD x 300mm long with ID to suit.

Note that the above parameters are a general guideline only and can often be exceeded if the need arises.

A general machining tolerance of +/-0.10mm is easily achievable and, with extra care, tolerances as low as +/- 0.01 are achievable depending on the size and shape of the component.

Most ground surfaces are within 0.5µm RA but flat surfaces can be polished to within 0.02µm RA and flat to <1λ per 25mm.

We are able to supply small batch quantities such as is required for R & D work as well as larger volumes for your production requirements.

Typical Properties

Max working temp °C 1900
Coefficient of Thermal Expansion °C 4.02 x 10-6 / °C
Knoop Hardness (100g) Kg/cm² 2800
Flexural Strength MPa
@ Room Temp 280
@ 1450°C 270
@ 1600°C 300
Compressive Strength Mpa
@ Room Temp 1725-2500
Modulus of Elasticity Gpa
@ 20°C 420
@1300°C 363
Thermal Conductivity W/m°C @ 1200°C 34.8
DC Volume Resistivity ohm.cm 1.0
Density g/cm³ 3.05