Technical Ceramics

Wonderstone is a Machinable mineral which, after heat treatment, assumes many of the attributes of fired ceramics. It can be turned, milled, tapped, sawn or drilled to a high degree of accuracy. Wonderstone, powder pressed, fired material can be engineered for enhanced refractory and physical properties.

Wonderstone can be held to closer dimensional tolerances than any other ceramic body that is not ground after firing. This allows for rapid prototyping and pilot scale productions. It has been used for coil forms and bars, electrical application parts, gas burner tips, welding cups and atomising nozzles. Wonderstone powder is also used as a filler in train brakes.

Components can also be pressed from powder; these components will display the following characteristics:

  • Excellent thermal shock resistance
  • Extremely low thermal expansion
  • Excellent chemical resistance
  • Good electrical insulation
  • Retaining strength up to maximum operating temperature of 1200 ºC
  • Melting point is at 1630 ºC
  • Very good heat retention and good thermal insulation

When heat treating the natural machined material, certain precautions need to be observed:

  • Sections need to be less than 13 mm otherwise thermal stresses could cause cracking
  • The heating rate should not be greater than 50 ºC per hour till 400 ºC then 100 ºC per hour to a maximum of 1300 ºC then held for an hour at the final temperature
  • When fired to a range 800 ºC - 1000 ºC expansion of 1.7 – 2% takes place and over this temperature, a gradual shrinkage is seen to within 101% of the machined size as the material densifies
  • Available in various sizes with maximum length of 300mm (11.8 inches).

The rods and/or tubes are substantially free from visible cracks but cannot be guaranteed. Seller will insure that all rods and/or tubes are suitably packed to preserve the material during transit.

Standard Products

Powder Pressed Wonderstone – Rods and Tubes (Cylinders):

Typical available sizes:

  • Available in various sizes with a maximum length of 300mm (11.8 inches)

The rods and/or tubes are substantially free from visible cracks but cannot be guaranteed. Seller will insure that all rods and/or tubes are suitably packed to preserve the material during transit.

Wonderstone (Pyrophyllite) Standard Powders:

Standard Coarse Powder:

  • +500 µm – (0%)
  • -500 µm + 300 µm - (25-35%)
  • -300 µm + 125 µm - (45-60%)
  • -125 µm + 45 µm- (12-25%)
  • -45 µm – (0-4%)

Standard Fine Powder:

  • +104 µm – (0 - 2.0%)
  • +63 µm – (0 - 10%)
  • -30 µm – (70 - 100%)