Do You Know What are The Special Requirements for The Chamber Design of a High Temperature Graphitization Furnace?

Release time:

2025-08-11

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Abstract

In the manufacture of high temperature graphitization furnace, the chamber design directly determines the performance and service life of the equipment. Unlike conventional heating equipment, graphitization furnace needs to withstand the extreme environment of 2000-3000 ℃, its cavity design must meet a series of special requirements.

Ⅰ. Selection of High Temperature Resistant Materials

1. Core Material Requirements

Graphite material: use high purity isostatically pressed graphite (purity >99.99%)

Metal parts: use high melting point metals such as tungsten and molybdenum (melting point >3000℃)

Insulation material: use pyrolytic boron nitride or zirconia ceramics

2. Key Parameter Indicators

Long-term working temperature ≥3000°C

High-temperature strength retention rate >80%

Thermal expansion coefficient <5×10-⁶/°C

Ⅱ. Multi-layer composite structure design

Modern high temperature graphitization furnace commonly used "sandwich" type composite structure:

Lining layer: direct contact with the high temperature zone, using high-purity graphite

Insulation layer: multi-layer carbon felt/graphite felt (thickness 50-100mm)

Reflective layer: molybdenum or tungsten metal foils

Shell layer: stainless steel water-cooled jacket

Ⅲ. Special sealing and atmosphere control

1. Vacuum sealing system

Double metal sealing (copper gasket + stainless steel flange)

Vacuum up to 10-³Pa

Leakage rate <1×10-⁹Pa-m³/s

2. Atmosphere control system

Inert gas (Ar/N₂) purity ≥99.999%

Flow rate control accuracy ±1%

Pressure range: 10-³Pa-0.1MPa adjustable

Ⅳ. the design of heat field uniformity

1. Heating element layout

adopts three-dimensional three-dimensional arrangement

Multi-zone independent temperature control (usually 4-8 zones)

Power density gradient design

2. Temperature uniformity guarantee

Temperature difference inside the furnace <±15℃ (at 2000℃)

Special design graphite heat equalization plate

Rotating sample holder design (optional)

Ⅴ. Special application scenario design

1. Continuous graphitization furnace

Segmented chamber design

Air curtain isolation device

Material transfer system

2. Ultra High Temperature Furnace (>3000℃)

Composite Heating System (Graphite + Induction Heating)

Multi-layer heat radiation shielding

Special observation window design (sapphire glass)

Ⅵ. Maintenance points

Regular inspection: monthly detection of cavity deformation (should be <0.5mm)

Cleaning specification: use special graphite cleaner

Parts replacement: heating element life is usually 200-500 hours

Performance verification: quarterly thermal field uniformity test

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