[en] The aim of present work was to develop Mo-blend composite coating using atmospheric plasma spray technique and to optimize its tribological properties such as temperature, frequency and load as process parameters, using Taguchi L9 orthogonal array (OA). The SEM microstructures also help in confirming the optimal process conditions for tribological properties of a composite coating, while EDS was used to confirm the elemental peaks of composite coating. HRXRD was used to confirm the phase deposition of composite coating. Calculation and prediction of optimum process parameters were done by using raw data and signal to noise (S/N) ratio of ANOVA (Analysis of variance). The significant process parameters for COF according to their contribution percentage are frequency (51.20) followed by the load (30.36%), and temperature (17.12%). The percentage contribution of frequency (87.81%) was highest followed by temperature (2.69%) and load (2.53%) for weight loss. (paper)

[en] In the present research study, Friction stir processing (FSP) has been utilized to prepare nano surface composites, AA7075 based matrix was reinforced with B₄C nanoparticles (size <30 nm). The aim of this study is to form a thin layer of B₄C over the surface of AA7075 based matrix material through Self-Assembled Monolayer (SAM) technique followed by Friction stir processing. The major advantage of SAM is to minimize the quantity of B₄C nanoparticles used in the preparation of nano surface composites. Additionally, this research also investigates the effect of tool rotation speed of Friction stir processing on mechanical and wear properties of processed nano surface composite. The results observed a uniform dispersion of nanoparticles in the processed nano surface composite and an improved value of microhardness with maximum value was found to be 185 Hv of the sample processed at 1200 rpm, compared to base metal. For the constant load, as FSP tool rotation speed increases, wear resistance increases from 1000 to 1200 rpm and decreases slightly for 1400 rpm. Scanning Electron Microscope (SEM) micrograph, tensile test and Field Emission Scanning-Electron Microscope (FESEM) fractography image used to study microstructure and the mechanical properties of processed nano surface composite. The x-ray Diffraction (XRD) showed the presence of B₄C nanoparticles. Processed nano surface composites can be used for aircraft and automobile industry applications. (paper)

[en] In the present work, author has successfully developed carbon coating for wear resistance applications using HVOF thermal spray process. The FESEM, OM and Raman spectra confirms the presence of sp¹, sp² and sp³ structured carbon phase in the carbon coating, having good mechanical properties (micro-hardness) and excellent tribological performance (COF and wear). The carbon coating was tested at variable temperature (30, 100, 200, 300, 400 °C). It was seen that, the micro-hardness of coating increases with temperature, due to formation of oxides and carbide layer in the coating. The experimental result of wear shows that carbon coating was temperature dependent and at 400 °C lowest COF (0.045), frictional force (0.9 N) and wear (12 μm) were obtained for carbon coating. (paper)

[en] In the present study, fabrication of surface composite using AA7075-T6 as a matrix material and boron carbide nanoparticles as reinforcement through Friction stir processing (FSP) has been done. FSP technique has been widely utilized for surface modification and the formation of composite material. The B₄C nanoparticles size (<30 nm) as reinforcement were padded in dimension of 2 mm width and 1.5 mm depth groove of AA7075-T6 plate as a matrix material. The single-pass process executed using a square tool pin with tool rotation and traverse speed of 1000 rpm and 40 mm min⁻¹ respectively. This research aims to observe and process Self-Assembled Monolayer (SAM), investigate the effect of the B₄C nano-ceramic particles on the AA7075-T6 and its mechanical properties of the nano-ceramic surface composite. Frictional and wear analysis investigations under various physical conditions have highlighted surface durability characteristics of the metal matrix composite of AA7075-T6. Microstructure results along with fractography-image highlight the homogeneous distribution of boron carbide nano-ceramic particle. Tensile test, Microhardness, microstructure, Field Emission Scanning-Electron Microscope (FESEM), and X-Ray Diffraction (XRD) analyzed the fabricated (Al + B₄C) nano-ceramic surface composite. The fabricated nano-ceramic surface composite could be utilized in lightweight applications such as aerospace, marine, defence, and automotive industry. (paper)

[en] The aim of present work was principally focus upon development of Mo composite coating using HVOF thermal spray coating process and to enhance residual stresses using Taguchi approach. The process parameter used in Taguchi experiment are Temperature, load and frequency. ANOVA method was used to examine and analyze the process parameters significance of Mo composite coating. The HRXRD and FESEM attached EDS were used to confirm surface morphology and presence of Mo based composite coating on steel substrate. Experimental results also concluded that for percent (%) change in residual stress, temperature (64.19%) has maximum % contribution followed by frequency (21.82%) and load (6.31%). (paper)

[en] The present research investigates the thermal and corrosive behaviour of alumina-based ceramic coatings deposited on stainless steel grade 304 through the flame spray method. The microstructure of the coatings was examined using various techniques such as FESEM, EDS, and a 3D optical profilometer. The thermal conductivity of the coatings was determined by employing the hot plate method to calculate the temperature difference across the exposed coatings. Furthermore, an electrochemical test was conducted to evaluate the corrosion behaviour of the deposited coatings. The outcomes of the study reveal that the Al₂O₃ – 40%TiO₂ coating exhibits significantly higher thermal and corrosive resistance characteristics in comparison to the stainless-steel substrate. (author)

[en] In the present scenario due to manufacturing revolution there is a huge demand of mechanical components having high surface finish and a long life cycle. Demand of high surface finish, leads to development of new techniques for nano finishing of intricate shapes, such as Abrasive flow machining (AFM) and hybrid forms of it. During the abrasive flow finishing process, abrasive particles impart a huge impact force on the work piece surface to increase surface finish. This research paper discuss about a newly developed thermal additive centrifugal abrasive flow machining process (TACAFM) and also develops a mathematical model for the material removal of developed process at a given thermal energy pulse. Novelty of TACAFM process reduced the force applied by the abrasive particles and also decreased the loss of energy. In this hybrid process abrasive particles can easily remove the molten/ semi molten material from the work surface under thermal spark mechanism. The experimental results showed material removal in case of TACAFM process is almost double in comparison of conventional AFM process. The oxide layers and molten material on work surface was also observed from SEM images, which clearly indicated the domination of thermal effect over AFM. Also the parameters were optimized for the residual stress in case of TACAFM process and optimum residual stress was found as −152.21 MPa, which shows compressive stress developed on the surface due to the thermal effect. The experimental result showed current is the most significant parameter in TACAFM process and its contribution was found as 91.8%. (paper)

[en] The principal aim of the present study is to develop carbon based composite coating for wear resistance, having excellent tribological properties and enhanced mechanical properties using atmospheric plasma spray coating technique. FESEM, and HRXRD results confirms the presence of Cr₃C₂, MoO₂ and Mo₂C along with Cr₂C₂, hard phased in the carbon based composite coating. The carbon based composite coating was wear tested at variable temperature, the hardness and residual stress of the coating increases with increase in wear temperature, due to the formation of oxides and carbide in the coating. The experimental result shows that carbon based composite coating was temperature dependent and at 350 °C temperature; lowest COF (0.08), wear (105 micron) and frictional force (3 N) was obtained. (paper)

[en] In the present research work, AA7075 composite reinforced with silicon carbide particles has been fabricated using Friction stir processing (FSP). The silicon carbide particles having a size of 40 μm were placed in grooves of length 160 mm, width 2 mm, depth 3.5 mm, that were generated on the AA7075 plate. The square pin tool is utilized for fabricating the composite at two different rotational speed i.e. 700 and 1000 rpm. Effect of processing, particle addition and tool rotational speed is analyzed on mechanical and wear properties of the material. On friction stir processing the microhardness value and elongation of the material increased. Reinforcement addition contributed to decrease in ductility and tensile strength while on the contrary microhardness and wear resistance of the material improved. Tool rotational speed showed a direct relation with the tested mechanical and wear properties. Adhesive wear was the prominent wear mechanism and Fe layer formation was observed on the worn surface, contributing to increased wear resistance. These fabricated composites can find vast application in industries like automotive, defence and aerospace. (paper)