Custom High Temperature MgO Ceramic Crucible

Magnesium oxide is an alkaline oxide with a high melting point, offering excellent chemical stability and heat resistance, making it suitable for processes involving molten metals, glass, ceramics, and other high-temperature treatments. Magnesium oxide crucibles are high-temperature resistant containers used for high-temperature experiments and industrial applications, primarily made from magnesium oxide (MgO). These crucibles are commonly employed in laboratories, metallurgy, chemical engineering, and materials science, particularly in scenarios requiring resistance to alkaline environments or high-temperature corrosion.

It is made of high-purity magnesium oxide (usually with a purity of over 99%) and has excellent high temperature resistance (maximum operating temperature of 2200 °C), wear resistance, corrosion resistance, and acid and alkali resistance. Magnesium oxide ceramics belong to the cubic crystal system, with a theoretical density of 2.8-3.2 g/cm ³ and a Mohs hardness of 5-6. They have a high specific volume resistance at high temperatures and good electrical insulation properties.

It is suitable for heating containers in medium and high frequency induction furnaces, electric furnaces, and vacuum furnaces, and can provide an inert and pollution-free environment to ensure high purity during the melting process.

In addition to the above characteristics, magnesium oxide crucibles also have good resistance to alkaline metal slag and can be used for smelting non-ferrous and precious metals such as platinum, rhodium, iridium, as well as vacuum melting high-purity radioactive metals such as uranium, thorium alloys, iron and their alloys.

In addition, it can also be used as a high-temperature thermocouple protection tube and a lining material for high-temperature furnaces.

Key Properties and Characteristics

• Extremely High Melting Point:

• MgO melts at approximately 2,852°C (5,166°F). This makes it one of the few materials suitable for containing metals and salts with melting points above 2000°C.

• Excellent Chemical Resistance:

• Basic Refractory: MgO is highly resistant to basic (alkaline) slags and environments. It is an excellent choice for melting nickel-based superalloys, cobalt, and precious metals like platinum, which can be corrosive to other oxide ceramics.
• Poor Acid Resistance: It is readily attacked by acidic slags and materials. It should not be used with highly acidic oxides like silica (SiO₂) or boron oxide at high temperatures.

• Thermal Stability:

• It has good thermal shock resistance, though it is generally inferior to alumina. This means heating and cooling should be controlled to avoid cracking.

• Electrical Insulator:

• Like most ceramics, it is an excellent electrical insulator at room temperature and high temperatures, making it suitable for induction furnaces and other electrically heated systems.

• Mechanical Strength:

• It has moderate mechanical strength at room temperature, but its strength decreases at very high temperatures.

Common Applications

MgO crucibles are used in demanding, high-temperature processes where other ceramics fail:

• Metallurgy & Alloy Development:

Melting and processing of reactive metals  (e.g., Titanium, Zirconium, and their alloys).

Processing platinum group metals (Platinum, Rhodium, etc.).

Melting uraniumand other nuclear materials.

• Crystal Growth:

Crucibles for the Czochralski process to grow single crystals of

high-melting-point oxides.

• Materials Science Research:

Used in labs for sintering, calcination, and heat treatment of advanced

ceramics and powders where contamination must be avoided.

• Glass Industry:

Occasionally used for containing certain types of specialty glasses,

particularly those with a basic composition.

Operation steps (taking metal melting as an example):

Preheating: Heat the crucible at a rate of 5-10 ° C/min to 500 ° C and hold for 1 hour.

Loading: Add metal material, with a filling amount not exceeding 80% of the crucible capacity.

Melting: Heat up at a rate of 10-15 ° C/min to the target temperature (usually 1200-1600 °C).

Insulation: Keep at the target temperature for 1-2 hours.

Cooling: Slowly cool to room temperature at a rate not exceeding 5 ° C/min. There are related products in the store now. Our zirconia ceramic crucible has a high purity of 99.9%, a Vickers hardness of 1250HV, and a density of 6.0g/cm ³. It can withstand high temperatures up to 1000 ° C and is suitable for various industrial fixed uses.

Important Handling and Usage Considerations

• Moisture Sensitivity (Slaking):

• This is the most critical factor. MgO reacts with water (H₂O) and carbon dioxide (CO₂) in the air to form magnesium hydroxide and carbonate, which causes the crucible to swell, crack, and disintegrate.
• Storage: Must be stored in a dry, airtight container, often with desiccant.
• Pre-firing: Before first use, it is often recommended to "condition" the crucible by heating it to a high temperature to drive off any absorbed moisture.

• Thermal Cycling:

• Avoid rapid heating and cooling. Always follow recommended heating and cooling rates to prevent thermal shock and cracking.

• Compatibility:

• Always check the chemical compatibility between the MgO crucible and the material you are melting or processing. Using it with an incompatible material (like an acidic oxide) will destroy the crucible quickly.

Technical Specifications