• SAEED REZA BAKHSHI

Articles written in Bulletin of Materials Science

• Investigation of TaC–TaB2 ceramic composites

The TaC–TaB2 composition was sintered by spark plasma (SPS) at 1900–2100°C and applied pressure of 30 MPa. TaC and 2–3 wt% B4C were used as starting powders. Densification process, phase evolution, microstructure and the mechanical properties of the composites were investigated. The results indicated that the TaC–TaB2 composition could be SPS to 97% of theoretical density in 10 min at 2100°C. Addition of B4C leads to an increase in the density sample from 76 to 97%. B4C nano-powder resists grain growth even at high temperature 2100°C. The formation of TaB2/carbon at TaC grain boundaries helps in pinning the grain boundary and inhibiting grain growth. The phase formation was associated with carbon and boron diffusion from the starting particles B4C to form TaB2 phases. TaC grain sizes decreased with increase in B4C concentration. Samples with 2.0 wt% B4C composition had highest flexure strength up to 520 MPa. The effect of B4C addition on hardness measured by microhardness has been studied. Hardness of samples containing 3.0 wt% B4C was 16.99 GPa.

• Investigation of chemical etching and surface modification effect on the superhydrophobic, self-cleaning and corrosion behaviour of aluminium substrate

In this study, superhydrophobic surfaces were fabricated on aluminium substrates by chemical etching method and surface modification with perfluorooctyl trichlorosilane (PFTS). The superhydrophobic surface of the aluminium substrate was synthesized by two-step process: first, the roughness on the aluminium surface was created by the chemical etching method. Then, the surface energy of the rough aluminium substrate was reduced by immersion in the PFTS solution. The surface wettability was measured by a droplet contact angle measurement. The morphology and chemical composition of the surface were detected by field emission scanning electron microscope and attenuated total reflection-Fourier transform infrared methods, respectively. The self-cleaning properties of the coated and bare aluminium substrates were investigated. Corrosion behaviour of the samples was evaluated using Tafel polarization and salt spray methods. The contact angle measurement results showed that the surface roughness due to chemical etching reduced the contact angle on the aluminium substrate to 24°and after surface modification, the contact angle increased to 157°. In the Tafel polarization test, after creating a superhydrophobic surface, the corrosion current density and corrosion potential of the aluminium substrate reached from 94.3 to 28.82 (${\mu}$A cm$^{-2}$) and -0.695 to -0.68 V, respectively. The superhydrophobic aluminium surface showed self-cleaning effect.

• # Bulletin of Materials Science

Volume 46, 2023
All articles
Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020