• VIJAYA AGARWALA

Articles written in Bulletin of Materials Science

• Synthesis and characterization of electroless Ni–P coated graphite particles

Electroless alkaline bath is used to coat Ni–P graphite particles of average size, 150 𝜇m. Amorphous nickel and graphite phases are observed in X-ray diffraction of the coated particles. The crystallite size from diffraction peaks is found to be 9.56 nm. The microstructural studies are carried out with field emission scanning electron microscope (SEM) on the uncoated and coated graphite particles. Uncoated particles showed irregular and fractured surfaces while the surface of coated particles revealed the presence of Ni–P globules. Sizes of Ni–P globules are observed to be in the range 175–250 nm. The presence of Ni and P are confirmed by the energy dispersive spectrometer results. The effect of coating bath composition is studied and an increasing trend in deposition is observed up to 50 gl–1 of stabilizer as well as up to 20 gl–1 of the reducing agent, however, the trend reverses afterwards. The phenomena of nucleation and growth of the Ni–P layer over the graphite surface have been demonstrated through SEM studies and a model has been proposed to demonstrate the growth mechanism of Ni–P globules.

• Microstructure and wear behaviour of FeAl-based composites containing in-situ carbides

Iron aluminides containing carbon are promising materials for tribological applications. Because of graphite formation at higher ($>$20 wt%) Al-contents the addition of carbon to FeAl-based alloys has not been successful.The graphite precipitation may be avoided by addition of Zr or Ti. Dry sliding wear behaviour of FeAl based alloys containing 1–1.5wt% carbon with quaternary addition of Ti or Zr has been studied using ball-on-disk wear test. Effect of sliding speeds and applied loads is investigated and correlated with mechanical properties. Wear resistance of FeAl-based alloys is found to be significantly improved on addition of Ti/Zr. This is attributed to the high hardness of alloy carbides. The lower load-bearing capacity of graphite flakes in localized region was found to increase the wear rate of the alloy. The carbides such as Fe$_3$AlC$_{0.5}$, TiC and ZrC are embedded in the matrix after sliding wear without destruction or delamination. This significantly affects the wear resistance of FeAl-based alloys.

• # Bulletin of Materials Science

Volume 44, 2021
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

Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
Physical Sciences 2020

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