Tribological Behavior of NiMoAl-Based Self-Lubricating Composites

Area of Science:

• Materials Science
• Tribology
• Composite Materials

Background:

• Developing self-lubricating composites is crucial for reducing friction and wear in mechanical components.
• NiMoAl alloys offer potential as matrix materials, but their tribological properties require enhancement.
• Incorporating solid lubricants like MoS2 and MAX phases can improve material performance.

Purpose of the Study:

• To develop novel NiMoAl-based self-lubricating composites using powder metallurgy.
• To investigate the effect of adding Cr2AlC MAX phase, Cr2AlC-Ag, and MoS2 as solid lubricants.
• To evaluate the tribo-mechanical properties and surface characteristics of the developed composites.

Main Methods:

• Powder metallurgy techniques, including mixing and hot pressing, were employed to fabricate composite samples.
• Hardness and wear resistance tests were conducted to assess mechanical performance.
• Scanning Kelvin probe microscopy and micro Raman spectroscopy were used to analyze tribofilm properties.

Main Results:

• Addition of MoS2, Cr2AlC MAX phase, and Cr2AlC-Ag enhanced the hardness and wear resistance of the NiMoAl matrix.
• Cr2AlC-based additions were more effective than MoS2 in improving wear resistance.
• The NiMoAl matrix with Cr2AlC-Ag exhibited superior tribo-mechanical properties, reducing wear rate by 33% and friction coefficient by 25%.

Conclusions:

• The addition of Cr2AlC-Ag to NiMoAl significantly improves tribo-mechanical properties.
• Enhanced performance is attributed to high sintered density and the formation of robust tribofilms containing Ag2MoO4 and Al2O3.
• These composites show promise for applications requiring self-lubrication and wear resistance.