Carburization of Tantalum Metal Powder Using Activated Carbon

Area of Science:

• Materials Science
• Solid State Chemistry
• Powder Metallurgy

Background:

• Tantalum carbide (TaC) is a refractory material known for hardness and thermal stability.
• High-purity tantalum metal powder was synthesized via magnesium thermal reduction of Ta2O5.

Purpose of the Study:

• Investigate the carburization behavior of tantalum metal powder.
• Evaluate activated carbon and graphite as carbon sources for TaC synthesis under vacuum.
• Analyze the effects of temperature and time on TaC formation.

Main Methods:

• Carburization experiments conducted at 1100-1400 °C for 5-20 hours under high vacuum.
• Carbon content analysis using combustion analysis.
• Phase identification and lattice parameter determination via X-ray diffraction.
• Microstructural analysis using Scanning Electron Microscopy (SEM).

Main Results:

• Activated carbon significantly improved carbon uptake versus graphite due to higher porosity and reactivity.
• Carbide phase progression observed: Ta -> Ta2C -> single-phase TaC with increasing carbon content.
• SEM revealed fine particle formation indicating local TaC nucleation.
• Near-theoretical lattice parameter (4.4547 Å) was approached, though stoichiometric carbon content was not fully achieved.

Conclusions:

• Activated carbon is an effective carburizing agent for synthesizing TaC under vacuum.
• The study provides insights into TaC formation mechanisms and phase transformations.
• Optimized conditions could lead to stoichiometric TaC with desired properties for high-temperature applications.