Recent research has shown that carbon nanotube (CNT) acts as a model reinforcement material for fabricating nanocomposites. The addition of CNT as a reinforcing material into the matrix improves the mechanical, thermal, tribological, and electrical properties. In this research paper multiwalled carbon nanotube (MWCNT), with different weight percentage (5%, 10%, and 15%), was reinforced into manganese dioxide (MnO₂) matrix using solution method. The different weight % of MWCNT/MnO₂nanocomposite powders was compacted and then sintered. The phase analysis, morphology, and chemical composition of the nanocomposites were examined by X-ray diffractometer, Field Emission Scanning Electron Microscope (FESEM), and Energy Dispersive X-Ray (EDX), respectively. The XRD analysis indicates the formation of MWCNT/MnO₂nanocomposites. The FESEM surface morphology analysis shows that MnO₂nanotube is densely grown on the surface of MWCNT. Further, microhardness of MWCNT/MnO₂nanocomposite was measured and it was found that 10 wt% has higher microhardness in comparison to 5 and 15 wt%. The microhardness of the composites is influenced by mass density, nanotube weight fraction, arrangement of tubes, and dispersion of MWCNT in H₂SO₄(aq) solution.

Wear parameter optimization is critical for the successful use of materials in load-bearing applications. This study examines the optimization of various wear parameters using the Taguchi technique for the determination of the specific wear rate of alpha-manganese dioxide (α-MnO₂)-epoxy nanocomposites. Four factors viz. wt.% loading of α-MnO₂, sliding distance, sliding velocity, and normal load, were selected as controllable factors and a suitable L₁₆ orthogonal array was chosen for conducting experiments. An X-ray diffractometer and field emission scanning electron microscope were used to examine phase identification, surface morphology, and chemical composition. With the addition of α-MnO₂ in the epoxy, the tensile stress is decreased, while the elastic modulus is increased. The Taguchi result shows that the wear test in optimal condition is carried out with a wt.% loading of α-MnO₂ of 0.5%, a sliding distance of 500 m, a sliding velocity of 1.5 m/s, and an applied normal load of 5 N. Analysis of variance shows the wt.% loading of α-MnO₂ has the most influential parameter on specific wear rate with a contribution of 87.94%. The analysis also shows that the general linear model accurately describes the effect of sliding wear parameters on specific wear rates. The Monte Carlo simulated model shows that the experimental signal-to-noise ratios are consistent with the simulated model values. The confirmation test result shows that the % error between the predicted and experimental values of the specific wear rate at the optimum level combination is 4.67%. The worm surfaces of different trial runs show that the material removal process is caused by crack propagation. High-resolution scanning electron microscopic images of fractured surfaces show the formation of a stable tribo-layer at 0.5 wt.% α-MnO₂ loading resulted in a significant decrease in the specific wear rate of the sample.

Tribology is the study of moving surfaces, and it has a variety of effects on our lives. From an economic point of view, wear is one of the most important aspects of an industry’s viability. Parts of the machine can wear out, and they need to be replaced. This is especially important for polymer-based materials. Therefore, it is important to reduce maintenance costs and improve machine reliability in a variety of engineering applications through proper material selection. The present investigation deals with the fabrication of manganese dioxide (MnO₂)/epoxy nanocomposite and investigates its tribological properties. The MnO₂/epoxy nanocomposites were fabricated via a solution mixing technique. The phase identification and surface morphology of the sample was examined by X-ray diffractometer and field emission scanning electron microscope, respectively. The mass density, micro-hardness, and specific wear rate data of samples revealed that the mass density, micro-hardness, and wear resistance of the samples increased with the addition of MnO₂ in the epoxy matrix. The nanocomposite sample containing 0.5 wt. % MnO₂ loading in the epoxy matrix shows higher density, micro-hardness, and wear resistance compared to other samples. The result also shows that with the addition of MnO₂ in the epoxy matrix, the coefficient of friction of the samples is increased. The percentage reduction in specific wear rate due to the addition of 0.5 wt. % MnO₂ in neat epoxy is 68.10%, whereas the percentage increase in the coefficient of friction is 19.30%. The results of the analysis of variance show the effect of adding wt. % of MnO₂ in the epoxy matrix is significant in the tribological responses. The worn surface analysis shows that the fatigue wear mode seems to be the dominating mode of wear for all samples as compared to the other modes of wear. The properties of MnO₂/epoxy nanocomposite data revealed that the developed material may be used in the automotive industry as a structural material, fabrication of snow sled, ball bearing housing, or plastic gear materials with adequate lubrication.