Crucibles Overview

All crucibles, alumina, magnesia and zirconia to name a few, are manufactured in Capital's own modern purpose-built facility in the Czech Republic where we press, cast and fire various materials into crucibles.

Product Range

Isopressed

Capital Refractories is able to supply a full range of isostatically pressed crucibles from 2 kg capacity to 75 kg, in different grades and qualities. We use a state-of-the-art semi-automated cold isostatic press. Cold isostatic pressing applies pressure to the workpiece in all directions producing products of uniform density. 

The advantages of Isostatically Pressed Crucibles are:

  • Wide range of qualities
  • Wide range of crucibles sizes
  • Smooth internal surface giving a reduction of inclusions
  • Consistent material properties throughout crucible
  • Defect-free - no casting bubbles etc
  • Uniform density throughout the product improving its resistance to thermal stress

Vibrocast

Crucibles are produced by vibration casting (vibrocast) when the required size or shape is uneconomical or impractical by the isopressing production method.

Capital Refractories can offer a range of vibration cast crucibles, including T-Pot Ladles:

Benefits
Complex shapes, e.g. internal pouring siphon

To complement our range of crucibles we also offer numerous ancillary products and materials used within the investment and related foundry industries.

Description

Quality Description
Alumina... General purpose crucible. Used for wide range of alloys.
.....AL97I Superior erosion resistance
.....AL88I Improved thermal shock resistance
Magnesia... High resistance to basic slags and titanium alloys. Used in vacuum melting of Ni, Co and Fe based alloys
.....MG88I Used in vacuum melting of Ni, Co and Fe based alloys
.....MG95I Resistant to the special alloys used in semi-conductor and sputter target industries
Zirconia High resistance to acid slags. Wide use in vacuummelting of superalloys.
.....ZC93I .....General applications.
.....ZC95I .....High thermal shock resistance.
.....ZC96I .....Fine grained structure.

Chemistry

Quality Al2O3 SiO2 MgO CaO Fe2O3 ZrO2 + HfO2
Alumina AL97I 97.5 1.6 - 0.1 <0.1 -
Alumina AL88I 88.5 9.4 - 0.1 0.2 -
Magnesia MG88I 3.5 3.8 88.0 3.8 0.2 -
Magnesia MG95I 0.5 0.8 95.0 2.5 0.1 -
Zirconia ZC93I 0.8 1.2 - 4.0 0.1 93.0
Zirconia ZC95I 1.0 1.5 - 3.8 <0.1 92.9
Zirconia ZC96I 0.6 0.9 - 4.4 0.1 94.0

Properties

Quality Bulk Density / g cm-3 Apparent Porosity / % Thermal Expansion / MK-1 Thermal Conductivity / W m-1 K-1 Maximum Service Temperature / °C
Alumina AL97I 2.95 23.8 8.0 4.2 1700
Alumina AL88I 2.59 23.8 8.0 4.2 1700
Magnesia MG88I 2.83 17.0 14.5 2.4 1700
Magnesia MG95I 2.95 15.0 13.0 2.5 1750
Zirconia ZC93I 4.35 20.0 8.4 1.5 1850
Zirconia ZC95I 4.50 18.5 8.5 1.6 1850
Zirconia ZC96I 4.50 18.5 8.5 1.6 1850

Brochure Request

Thank you

Your brochure is ready for download.

Download brochure