Showing 3 results for Sajja
H. Shalchian, A. Farbod, H. Beygi, S. A. Sajjadi,
Volume 12, Issue 1 (march 2015 2015)
Abstract
High energetic aluminum nanoparticles are mainly used as additive in solid rocket propellants. However,
fabrication of these aluminized energetic materials is associated with decreasing the burning rate of propellants due
to problems such as oxidation and agglomeration of nanoparticles. In this study, to improve combustion performance
of aluminum nanoparticles, coating by metallic Ni shell was studied. Nickel coating of aluminum nanoparticles was
performed through electroless deposition (ED) subsequently, morphology and chemical composition of Ni-coated
nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM),
energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). These studies show that a uniform Ni layer with a
thickness of 10nm is coated on the surface of Al nanoparticles. Thermal analysis of uncoated and Ni-coated aluminum
nanoparticles was done using differential thermal analysis (DTA) and thermo gravimetric analysis (TGA). The results
of thermal analysis indicate that, coating the aluminum particles by Ni, leads to improvement in combustion
performance of aluminum nanoparticles through decreasing critical ignition temperature, ignition delay time of the
nanoparticles and promoting the ignition by exothermic chemical reactions between Al and Ni
Sandeep Ramasamy Periasamy, Vaira Vignesh Ramalingam, Ajay Vijayakumar, Harieharran Senthilkumaran, Vyomateja Sajja, Padmanaban Ramasamy, Samuel Ratna Kumar Kumar Paul Sureshkumar ,
Volume 20, Issue 2 (June 2023)
Abstract
Novelty: Most of the open literature research has focused on the microstructural evolution and mechanical properties of AA2050 alloy. Also, a significant study discusses the corrosion behavior of AA2050 alloy based on immersion and electrochemical characteristics. The influence of heat treatment on the microstructure and mechanical properties of friction stir processed AA2050 alloy is scarcely discussed in the open literature. The hot salt corrosion characteristics of friction stir processed AA2050 seldom exists in the available literature. This study concentrates on microhardness, tensile strength, and corrosion properties of friction stir processed AA2050. Also, the work focuses on the influence of artificial aging on the microhardness, and tensile strength of the friction stir processed AA2050.
Sajjad Jameel Ibrahim Al Safawee, Ali Rasooli, Taher Rabizadeh,
Volume 21, Issue 0 (IN PRESS 2024)
Abstract
There is a global need to develop engineering materials to address the increasing demands in various industries. Spark plasma sintering (SPS) is one of the most distinguished powder metallurgy techniques, offering the opportunity for the fabrication of different types of materials. This work emphasizes optimizations of the important process parameters, including temperature, pressure, and holding time, involved in the SPS of the WC, WC-Co, and WC-Cr, as well as assessing the influence of the content of the Co (6-24 wt.%) and Cr (0.2-1 wt.%) binders on the overall characteristics of the SPS-ed cermets. The results illustrate that the process parameters highly affect the physicomechanical properties of the SPS-ed WC, where the most appropriate conditions from a physicomechanical viewpoint are obtained at a sintering temperature of 1700 °C, a pressure of 80 MPa, and a holding time of 5 min. The included Co binder reduces the optimum temperature and pressure down to 1200 °C and 70 MPa, respectively. The addition of the Co improves the final properties of the WC irrespective of its content. The highest tribomechanical properties are attained when 18 wt. % of Co is added. Similar to that of Co, the incorporation of Cr into the WC increases the tribomechanical performance. In general, the use of Co and Cr metallic binders seems a useful strategy to promote the overall properties of the SPS-ed WC.
