Investigations on the temperature-dependent tribological behaviour of spark plasma sintered CNT-304 SS self-lubricating nanocomposites

ABSTRACT

Herein, we report the tribological behaviour of CNT-304 stainless steel composites at room (28°C) and high temperatures (200°C). Nanocomposites of various CNT concentrations, namely 0.2, 0.5, 1.0, 2.0, 3.0, and 4.0 wt%, were prepared. A significant amount of grain refinement resulted in an increase in CNT loading. A tribological study was carried out at 28°C and 200°C. Wear resistance was found to enhance with an increase in CNT concentration at both temperatures. However, a slightly higher wear rate was observed at 200°C for the samples with CNT content < 3 wt% than their corresponding low-temperature values. About 86%, 91% drop-in wear rate was seen in 2.0 wt% CNT-304 SS, and 4.0 wt% CNT-304SS, respectively, as compared to pure SS at 28°C, which is 54% and 88% decrease at 200°C and is very promising. The decrease in wear volume with CNT content at both temperatures can be ascribed to the self-lubricating and reinforcing nature of CNTs in the metal matrix composites. Severe abrasive wear in the pristine SS samples was slowly changed to mild abrasive and lubricated wear in composites. A systematic study on the tribological behaviour of CNT-SS composites can shed light on the benefits and detriments of using them for various applications.

Highlights

• Incorporation of CNTs into 304 SS matrix caused grain refinement.

• Wear rate decreased with CNT content and 4.0 wt% CNT-SS showed minimum wear rate while pristine gave the maximum at both 28°C and 200°C.

• About 86% and 54% decrease in wear rate were observed for 2.0 wt% CNT-304 SS at 28°C and 200°C respectively as compared to the pristine 304 SS sample.

• Wear rate at 200°C was slightly more than that of room temperature (28°C) for CNT content < 3 wt%.

• The 3.0 wt% CNT-304 SS and 4.0 wt% CNT-304 SS showed nearly the same wear rate at both ambient and 200°C test.

GRAPHICAL ABSTRACT

KEYWORDS:

• Metal-matrix composites
• 304 stainless steel
• Carbon nanotubes
• Spark plasma sintering
• Friction
• Wear
• Self lubrication
• Temperature dependence

Disclosure statement

No potential conflict of interest was reported by the authors.