Browsing by Author "Augustin, A."

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Characterization of DC Magnetron Sputtered Copper Thin Film on Aluminium Touch Surface
(Springer, 2019) Augustin, A.; Rajendra Udupa, K.; Udaya Bhat, K.
Hospital care-assisted infections introduce problems like prolonged hospital stay, additional financial burden and higher death rate. Since copper is registered by US Environmental Protection Agency as the only solid antimicrobial metal, it could be used in hospital touch surfaces. In the present work, copper has been deposited on the aluminium substrate by DC magnetron sputtering method with different target power. Prior to the coating, the substrate has undergone double zincation process. The coating has been characterized by XRD, SEM, TEM, scratch hardness test and microhardness test. From the TEM micrographs, the grain size has been found to decrease from 49 to 18 nm on increasing the deposition power from 50 to 150 W. Along with the decrease in the grain size, the mechanical properties like scratch hardness and microhardness of the coating have been increased. The preferred growth along [111] direction observed in XRD analysis is responsible for the increase in the hardness of the coating apart from the presence of the nano-grains. The SEM image of the coating shows nodular morphology which enhances the surface area. © 2019, The Indian Institute of Metals - IIM.
Crystallite size measurement and micro-strain analysis of electrodeposited copper thin film using Williamson-Hall method
(2016) Augustin, A.; Rajendra, Udupa, K.; Udaya, Bhat, K.
The improvement in hydrophilicity of copper coating on aluminium for better antimicrobial activity can be achieved by increase in surface energy. The surface energy depends on the micro-strain of the coating. Micro-strain in the coatingincreases with reduction in crystallite size. In this investigation, the crystallite size in the electrodeposited copper coating was varied by varying deposition current density. Crystallite size and micro-strain in the coating were estimated using Williamson-Hall method. Values of crystallite sizes using TEM micrographs were in agreement with that using Williamson-Hall method. Also, presence of nano-Twins in the coating contributed for micro-strain in copper coating. � 2016 Author(s).
Crystallite size measurement and micro-strain analysis of electrodeposited copper thin film using Williamson-Hall method
(American Institute of Physics Inc. subs@aip.org, 2016) Augustin, A.; Rajendra Udupa, K.; Bhat, K.U.
The improvement in hydrophilicity of copper coating on aluminium for better antimicrobial activity can be achieved by increase in surface energy. The surface energy depends on the micro-strain of the coating. Micro-strain in the coatingincreases with reduction in crystallite size. In this investigation, the crystallite size in the electrodeposited copper coating was varied by varying deposition current density. Crystallite size and micro-strain in the coating were estimated using Williamson-Hall method. Values of crystallite sizes using TEM micrographs were in agreement with that using Williamson-Hall method. Also, presence of nano-Twins in the coating contributed for micro-strain in copper coating. Â© 2016 Author(s).
Effect of current density during electrodeposition on microstructure and hardness of textured Cu coating in the application of antimicrobial Al touch surface
(Elsevier Ltd, 2016) Augustin, A.; Huilgol, P.; Udupa, K.R.; Bhat, K.U.
Copper is a well proven antimicrobial material which can be used in the form of a coating on the touch surfaces. Those coating can offer a good service as touch surface for very long time if only they possess good mechanical properties like scratch resistance and microhardness. In the present work the above mentioned mechanical properties were determined on the electrodeposited copper thin film; deposited on double zincated aluminium. During deposition, current density was varied from 2 A dm?2 to 10 A dm?2, to produce crystallite size in the range of 33.5 nm to 66 nm. The crystallite size was calculated from the X-ray peak broadening (Scherrer?s formula) which were later confirmed by TEM micrographs. The scratch hardness and microhardness of the coating were measured and correlated with the crystallite size in the copper coating. Both characteristic values were found to increase with the reduction in crystallite size. Reduced crystallite size (Hall–Petch effect) and preferred growth of copper films along (111) plane play a significant role on the increase in the hardness of the coating. Further, TEM analysis reveals the presence of nano-twins in the film deposited at higher current density, which contributed to a large extent to the sharp increase of coating hardness compared to the mechanism of Hall–Petch effect. The antimicrobial ability of the coated sample has been evaluated against Escherichia coli bacteria and which is compared with that of commercially available bulk copper using the colony count method. 94% of E. coli cells were died after six hours of exposure to the copper coated surface. The morphology of the copper treated cells was studied using SEM. © 2016 Elsevier Ltd
Electron microscopic study of nodules formed during electrodeposition of copper on aluminium
(2015) Augustin, A.; Bhat, K.U.; Udupa, K.R.; Hegde, A.C.
Copper thin film was deposited on double zincated aluminium using electrodeposition route. To understand the growth behavior of copper nodules, deposition was done by varying coating current density. The topography and cross section of the coating was analyzed by using SEM. The structural details of copper nodules were studied by using TEM. Deposited copper thin film was made up of pomegranate like nodules with size varying from 5 ?m to 8 ?m, varying as a function of coating current density. At higher current density, the coating was made up of multiple layers of nodules having defects like twins, dislocations and stacking faults. The nodules had fine crystallites of size in the range of 50 nm. � (2015) Trans Tech Publications, Switzerland.
Electron microscopic study of nodules formed during electrodeposition of copper on aluminium
(Trans Tech Publications Ltd ttp@transtec.ch, 2015) Augustin, A.; Bhat, K.; Udupa, K.R.; Hegde, A.C.
Copper thin film was deposited on double zincated aluminium using electrodeposition route. To understand the growth behavior of copper nodules, deposition was done by varying coating current density. The topography and cross section of the coating was analyzed by using SEM. The structural details of copper nodules were studied by using TEM. Deposited copper thin film was made up of pomegranate like nodules with size varying from 5 Î¼m to 8 Î¼m, varying as a function of coating current density. At higher current density, the coating was made up of multiple layers of nodules having defects like twins, dislocations and stacking faults. The nodules had fine crystallites of size in the range of 50 nm. Â© (2015) Trans Tech Publications, Switzerland.