G.V.S. Nageswara Rao

Synthesis and characterization of copper nanoparticles by chemical reduction method

Copper nanoparticles were synthesized using chemical reduction method by reduction of copper sulphate as a metal precursor and sodium borohydride as reducing agent. The particles are characterized and assessed by UV-Vis spectrometer, SEM-EDS and particle size analysis. SEM-EDS and particle size analysis contributed to the analysis of size, shape and composition of copper nanoparticles. UV-Vis spectrometer contributed to analysis of optical properties of the nanoparticles which showed a 550nm and 800nm copper band. The SEM images are also observed and found to be in agreement with the UV-Vis result, confirming the formation of metallic copper nanoparticles. The average particle size at room temperature was less than 16nm. The sizes of the nanoparticles are more controllable by the chemical reduction method.

Effect of cobalt addition on microstructure and mechanical properties of tungsten heavy alloys

The present investigation attempts to study the microstructure and mechanical behaviour of tungsten heavy alloys with different cobalt content. Alloys with 2 and 3% cobalt were synthesized using liquid phase sintering technique. The alloys were then vacuum heat treated and finally swaged. Quantitative microstructural analyses were undertaken by determining tungsten grain size, contiguity of tungsten and volume fraction of the matrix etc. Tensile results showed that the alloy with 3% cobalt exhibited inferior properties as compared to 2% cobalt alloy. Detailed microstructural and fractographic analysis were undertaken in order to understand these trends. Work hardening analysis showed the double slope behaviour of the alloys, which could be attributed to change in deformation behaviour from single phase matrix to two phase aggregate. It was also concluded that higher cobalt alloys needed further optimization in terms of thermo-mechanical treatment in order to realize their full potential in terms of mechanical properties.

Strategies to synthesize various nanostructures of silver and their applications – a review

Due to their various beneficial application-based properties, such as behavior, structure, and size, the synthesis of silver nanoparticles (Ag-NPs) with different structures has become an interesting yet common task for researchers to produce nanostructures for applications in various fields. This is because silver nanoparticles have interesting and unique properties, such as optical and catalytic, resulting from their different structures and sizes. These properties extend the use of nanostructures in various fields of research, especially in medicine, pharmacy, electronics, etc. Also, variations in their parameters affect the structures and sizes of Ag-NPs. This review provides an overview/brief presentation of various methodologies used to synthesize different application-based silver nanoparticles and lists areas where these nanoparticles are suitable for use according to their specific structures and sizes.

Strategies to synthesise copper oxide nanoparticles and their bio applications – a review

ABSTRACT Researchers have identified copper oxide nanoparticles (CuO-NPs) as a key of interest because of their unique shape- and size-dependent bio-medical properties. Researchers have discovered and invented a variety of methods for the synthesis of CuO-NPs under physical, chemical and biological approach. In this review paper, we give an overview of the preparation of CuO-NPs through various methods and also their applications in the bio-medical field. The main aim of this paper is to keep up to date with the myriad ongoing methods of NPs’ synthesis and also examine their applications, especially in the field of medicine.

Influence of thermo-mechanical treatment in ferritic phase field on microstructure and mechanical properties of reduced activation ferritic-martensitic steel

The present study focuses on the evaluation of microstructure and mechanical properties of reduced activation ferritic-martensitic (RAFM) steel (9Cr-1W-0.06Ta) subjected to thermo-mechanical treatment (TMT) in ferritic phase field. The results obtained were compared with the steel in conventional normalised plus tempered (N+T) condition. The microstructure of the steel in N+T and TMT conditions was assessed by optical and scanning electron microscopes. Hardness, tensile and creep studies were carried out and the results were correlated with the microstructural studies. While the TMT processed steel resulted in coarser prior austenite grains and exhibited ferritic microstructure with large distribution of fine M23C6 and MX precipitates, the N+T steel reveals tempered martensitic structure with finer prior austenitic grains with coarser M23C6 and MX precipitates. Although ferritic structure is present in TMT processed steel, it exhibits better tensile and creep rupture strengths than N+T steel due to the presence of increased dislocation density and finer distribution of precipitates.