WEAR PERFORMANCE AND MECHANICAL PROPERTIES OF PLASMA SPRAYED GRAPHENE ENCAPSULATED RUTILE TiO2 COATING ON Al 6061-T6 S. KRISHNANUNNI, R. S. PRAKASH, J. PAUL Surface Review and Letters, 2025 Aluminium alloys, particularly the Al6061 variant, are highly valued in engineering applications for their favorable properties, such as excellent toughness, corrosion resistance, and mechanical strength. The automotive and aerospace industries are increasingly relying on these alloys due to their lightweight and high-strength characteristics. However, the low hardness and poor tribological properties of aluminium alloys necessitate surface modifications to expand their applicability. This study explores the impact of graphene and rutile TiO2 coatings on the mechanical and wear characteristics of Al 6061-T6 alloy, applied using plasma spray techniques. Plasma spraying a mixture of 2[Formula: see text]wt% graphene and 98[Formula: see text]wt% rutile TiO2 onto the aluminium surface resulted in a heterogeneous surface morphology with distinct phases of graphene and rutile TiO2 revealed through SEM and EDS. XRD confirmed the rutile phase in the coating, and Raman spectroscopy identified molecular vibrations corresponding to TiO2. Hardness testing results indicated a significant increase in hardness for the coated samples (921.75[Formula: see text]HV) compared to uncoated Al 6061-T6 (48.26[Formula: see text]HV). Wear testing under dry sliding conditions showed enhanced tribological properties for the coated samples, including lower coefficients of friction and reduced wear rates across various loads (10 N, 15 N, and 20 N). SEM images of wear tracks revealed that the coatings effectively minimized abrasive and adhesive wear, especially under higher loads. Specific and linear wear rate analyses further emphasized the coating’s ability to improve wear resistance. The investigation confirms that the G-TiO2 plasma-sprayed coating significantly enhances the hardness and wear performance of Al 6061-T6, making it a promising surface modification for applications requiring improved mechanical properties and durability.
Coating solutions for enhancing automotive brake disc durability against corrosion and wear—a review Krishnanunni S, Jinu Paul, Prakash R S Engineering Research Express, 2024 The automotive industry’s relentless pursuit of improved safety, performance, and durability has spurred a continuous search for innovative solutions for crucial components like brake discs. These components endure extreme thermal and mechanical stresses, making them highly susceptible to corrosion and wear. Inadequate corrosion resistance and excessive wear of brake disc material during service remain significant concerns, with the latter resulting in brake emissions in the form of dust and particulate matter that pose health risks to humans. As exhaust emission standards grow more stringent, it becomes imperative to address brake disc wear issues while maintaining material braking performance. This paper extensively examines recent brake disc coating advancements specifically designed to combat corrosion and wear challenges. It explores how these protective coatings interact with the broader automotive ecosystem, highlighting their pivotal role in ensuring safer, more resilient, and environmentally responsible vehicles. This paper also evaluates traditional coating technologies and materials alongside emerging alternatives for brake disc applications.
Influence of retrogression and reaging treatment on intergranular corrosion resistance and exfoliation corrosion resistance in AA7010 aluminum alloy S. Krishnanunni, R. Ranganatha, V. Anil Kumar, R. K. Gupta, G. Ajithkumar Materials Performance and Characterization, 2021 The aluminum alloys with zinc as the primary alloying element (AA7XXX series) exhibit high strength and are widely used as aircraft structural materials. These categories of aluminum alloys in their peak aging condition (T6) are known to be highly susceptible to general as well as stress corrosion cracking (SCC). Retrogression and reaging (RRA) treatment of this category of alloys leads to improvement in the corrosion resistance without significant compromise in strength. SCC was found to be improving in general in these alloys, but the intergranular corrosion (IGC) and exfoliation corrosion (EXCO) need to be evaluated. The effect of RRA heat treatment on the IGC and exfoliation of AA7010 aluminum alloy has been investigated and compared with T6 and T73 temper conditions of the alloy. The results indicate that the corrosion susceptibility of AA7010 aluminum alloy decreased by subjecting the alloy to multistage (RRA) heat treatment. It is attributed to the grain boundary precipitate coarsening and is also the major factor responsible for reducing the susceptibility to IGC and EXCO.
WEAR PERFORMANCE AND MECHANICAL PROPERTIES OF PLASMA SPRAYED GRAPHENE ENCAPSULATED RUTILE TiO 2 COATING ON Al 6061-T6 S Krishnanunni, RS Prakash, J Paul Surface Review and Letters, 2550183 , 2025 2025
SS304 Micro-interlayered low alloy steel prepared via cold metal transfer based wire Arc additive manufacturing V Babu, S Krishnanunni, J Paul Metallography, Microstructure, and Analysis 14 (2), 435-449 , 2025 2025 Citations: 2
Coating solutions for enhancing automotive brake disc durability against corrosion and wear—a review S Krishnanunni, J Paul, RS Prakash Engineering Research Express 6 (2), 022502 , 2024 2024 Citations: 9
Influence of Retrogression and Reaging Treatment on Intergranular Corrosion Resistance and Exfoliation Corrosion Resistance in AA7010 Aluminum Alloy S Krishnanunni, R Ranganatha, V Anil Kumar, RK Gupta, G Ajithkumar Materials Performance and Characterization 10 (1), 1-10 , 2021 2021 Citations: 2
Investigation on effect of optimized RRA in strength and SCC resistance for aluminium alloy AA7010 S Krishnanunni, RK Gupta, G Ajithkumar, VA Kumar, R Ghosh Materials Today: Proceedings 27, 2385-2389 , 2020 2020 Citations: 18
Optimization of heat treatment cycles and characterization of aluminum alloy AA7010 S Krishnanunni, RK Gupta, G Ajithkumar, V Anil Kumar Journal of Materials Engineering and Performance 28 (2), 776-787 , 2019 2019 Citations: 8
Evaluation of heat losses in fire tube boiler S Krishnanunni, J Paul, M Potti, EM Mathew International Journal of Emerging Technology and Advanced Engineering 2 (12 … , 2012 2012 Citations: 21
Effect of welding conditions on hardness of commercially pure titanium S Krishnanunni, DJ Paul, V Unni Akgec Int. J. Technol 3 (2), 19-24 , 2011 2011 Citations: 5
MOST CITED SCHOLAR PUBLICATIONS
Evaluation of heat losses in fire tube boiler S Krishnanunni, J Paul, M Potti, EM Mathew International Journal of Emerging Technology and Advanced Engineering 2 (12 … , 2012 2012 Citations: 21
Investigation on effect of optimized RRA in strength and SCC resistance for aluminium alloy AA7010 S Krishnanunni, RK Gupta, G Ajithkumar, VA Kumar, R Ghosh Materials Today: Proceedings 27, 2385-2389 , 2020 2020 Citations: 18
Coating solutions for enhancing automotive brake disc durability against corrosion and wear—a review S Krishnanunni, J Paul, RS Prakash Engineering Research Express 6 (2), 022502 , 2024 2024 Citations: 9
Optimization of heat treatment cycles and characterization of aluminum alloy AA7010 S Krishnanunni, RK Gupta, G Ajithkumar, V Anil Kumar Journal of Materials Engineering and Performance 28 (2), 776-787 , 2019 2019 Citations: 8
Effect of welding conditions on hardness of commercially pure titanium S Krishnanunni, DJ Paul, V Unni Akgec Int. J. Technol 3 (2), 19-24 , 2011 2011 Citations: 5
SS304 Micro-interlayered low alloy steel prepared via cold metal transfer based wire Arc additive manufacturing V Babu, S Krishnanunni, J Paul Metallography, Microstructure, and Analysis 14 (2), 435-449 , 2025 2025 Citations: 2
Influence of Retrogression and Reaging Treatment on Intergranular Corrosion Resistance and Exfoliation Corrosion Resistance in AA7010 Aluminum Alloy S Krishnanunni, R Ranganatha, V Anil Kumar, RK Gupta, G Ajithkumar Materials Performance and Characterization 10 (1), 1-10 , 2021 2021 Citations: 2
WEAR PERFORMANCE AND MECHANICAL PROPERTIES OF PLASMA SPRAYED GRAPHENE ENCAPSULATED RUTILE TiO 2 COATING ON Al 6061-T6 S Krishnanunni, RS Prakash, J Paul Surface Review and Letters, 2550183 , 2025 2025
