Strengthening Ni-Coated CNT/Mg Composites by Optimizing the CNT Content

Area of Science:

• Materials Science
• Nanotechnology
• Composite Materials

Background:

• Dispersion of carbon nanotubes (CNTs) is a critical challenge in developing CNT-reinforced metal matrix composites.
• Achieving uniform CNT distribution is essential for realizing their full potential in enhancing material properties.

Purpose of the Study:

• To prepare CNT/Mg composites with improved CNT dispersion and enhanced mechanical properties.
• To investigate the effect of nickel-coated CNT content on the microstructure and mechanical behavior of magnesium composites.

Main Methods:

• Magnesium powder was ground, and nickel-coated CNTs were dispersed using ball milling and hot pressing.
• Microstructural analysis was performed using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and optical microscopy.
• Mechanical properties were evaluated through compression tests.

Main Results:

• Uniform distribution of Ni-coated CNTs was achieved at CNT content below 1%, leading to a significant increase in composite strength.
• Higher CNT content resulted in CNT clustering, decreased fracture strain, and reduced strength.
• The nickel coating on CNTs reacted with the magnesium matrix to form Mg2Ni, enhancing interfacial bonding.

Conclusions:

• Optimizing Ni-coated CNT content is crucial for uniform dispersion and enhanced mechanical strength in CNT/Mg composites.
• The formation of Mg2Ni at the interface significantly strengthens the composite by improving bonding and acting as a reinforcing phase.