Faculty Publications

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Author: search.filters.author.Kattimani, S.Subject: search.filters.subject.Ceramic materials

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    Tribological performance and 3-D surface characterisation of age-hardened Al2090-based ceramic composites
    (SAGE Publications Ltd, 2025) Sharath, B.N.; Mahesh, V.; Mahesh, V.; Kattimani, S.; Harursampath, D.
    This study investigates the synergistic influence of boron nitride (BN) tertiary ceramic additives and age-hardening treatment on the microhardness and wear resistance of Al2090-based hybrid composites, fabricated using the stir casting method. X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM) studies are carried out to assess the phases present, microstructure, and surface properties, respectively. The metallurgical investigations confirm a relatively superior uniformity in the distribution of particles and the ageing of precipitation at 150°C, vis-à-vis the other temperatures explored in this study. The experimental examinations conducted as per ASTM (E8 and G99) standards revealed a significant improvement in both the hardness and the primary tribological properties, when micron-sized boron carbide, graphite, and boron nitride were used as reinforcements. Age-hardened samples, especially the hybrid composite HS-2 with 5 wt.% each of boron carbide, graphite, and boron nitride, demonstrated an enhanced hardness of 25.23% and lower surface roughness (44.3 nm) compared to Al2090 (AS), due to the presence of load-bearing ceramic reinforcements. Increasing the applied load led to higher wear rates and coefficients of friction for Al2090. However, heat-treated hybrid metal matrix composites (HMMCs) exhibited a contrary behaviour, suggesting enhanced durability. The investigation highlighted the better wear resistance of heat-treated and near-optimally reinforced HMMCs, indicating their potential candidature for wear-resistant aerospace applications. © IMechE 2025.
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    Investigation of dielectric properties and shore hardness of 3D-printed PLA core sandwich disc with functional ceramics surface cladding
    (KeAi Publishing Communications Ltd., 2025) Senthil Murugan, S.S.; Kattimani, S.; Bharadwaj, N.
    Poly-lactic acid (PLA), a popular biodegradable polymer for 3D printing, has limited dielectric strength and surface hardness, restricting its use in advanced electronic and structural applications. Existing enhancement methods are often complex or yield inconsistent results. Therefore, a straightforward and scalable approach is necessary to enhance the properties of 3D-printed PLA. This study aims to explore the enhancement of the dielectric and surface hardness of printed PLA discs through surface cladding using nano-functional ceramics and graphene for next-generation multifunctional applications. PLA discs were fabricated via Fused Deposition Modelling (FDM) and subsequently cladded using hand layup with Araldite resin as a binder. Cladding materials included cobalt ferrite (CF), barium titanate (BTO), and graphene (Gr), individually and in combinations. Dielectric properties—capacitance, impedance, dielectric constant, dielectric loss, dissipation factor, and AC conductivity—were analyzed using an impedance analyzer, while surface hardness was measured using a Shore-D durometer. Results revealed that cladding led to uniform particle dispersion with effective surface bonding, improved dielectric performance, and significantly enhanced surface hardness. The CF + BTO + Gr combination exhibited superior dielectric behaviour, balancing high polarization with low energy dissipation, while BTO contributed to an enhanced dielectric constant and graphene improved charge transfer. All cladded samples showed frequency-dependent dielectric responses, with stability at higher frequencies. The highest surface hardness was achieved with CF + BTO, attributed to rigid, uniform reinforcement. © 2025 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltdé This is an open access article under the CC BY-NC-ND license. http://creativecommons.org/licenses/by-nc-nd/4.0/