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Impact of sputtering gas on the microstructural, mechanical and wetting properties of vanadium nitride coatings
No full textVanadium nitride (VN) coatings were deposited via reactive DC magnetron sputtering technique on a hot substrate (400 degrees C) with varying partial pressure of N2. The impact of nitrogen partial pressure on the crystal structure, microstructure, elemental composition, surface topography, mechanical and wetting properties of VN coatings was investigated using grazing incidence X-ray diffraction (GIXRD), Raman spectroscopy, field emission scanning electron microscope (FESEM), energy dispersive spectroscopy (EDS), atomic force microscope (AFM), nano-indentation, and drop shape analyzer (DSA). The variation in the N2 partial pressure leads the significant changes in the microstructure, mechanical, and wetting properties of the coatings. The GIXRD spectra reveal the formation of crystalline FCC phase in the deposited VN coatings. However, at 100% N2 partial pressure, the preferred orientation of crystal planes changes from (200) to (220). The FESEM image reveals that at low N2 partial pressure, the coating exhibits well-separated grains with clearly visible grain boundaries. As the N2 partial pressure increases, the agglomeration of grains becomes more pronounced, and the grain boundaries become less discernible. However, at 100% N2 partial pressure, the structure transforms into triangular nanoflake-like prismatic structures with voids. The VN coatings with 60% N2 partial pressure exhibit the highest mechanical properties whereas at 100% N2 partial pressure, the VN coatings reveal a super-hydrophilic character
Material Recycling: Unearthing Metals from Anthropogenic and Industrial Resources
No full textGiven the need to achieve sustainability in material processing, the present chapter emphasizes exploring secondary resources as sustainable alternates to primary ores via replenishment cum recycling of anthropogenic and industrial wastes. These resources often contain metals in lower values except in a few cases like WEEEs; but processing of such is benign to the environment, economical, and ensures extended producer responsibility
Probability Analysis in Predicting Creep Life of Power Plant Material Using High Power Ultrasound
No full textNonlinear ultrasonic (NLU) has been established as an effective method for the non-destructive evaluation
of power plant materials for various types of damage, including estimation of creep damage. However, the
information obtained through NLU measurement may not be sufficient to predict either the failure
probability or remaining creep life of any power plant component. A procedure has been formulated to
estimate the probability of failure vis-a-vis creep life of power plant materials through a two-parameter
Weibull analysis of NLU data. The investigation involved creep testing of P92 steel at 625 C for three
different applied stresses 120, 140, and 160 MPa. Subsequently, the extent of damage was estimated using
Weibull distribution analysis from NLU parameter b, measured in the same specimen at different interruptions.
The variation in cumulative distribution function (CDF) and the damage accumulation rate with
increased damage, were examined. Further, the behavior of predicted NLU parameter b obtained using
inverse CDF was evaluated with respect to measured b. Damage accumulation during creep deformation
was confirmed through significant microstructural changes such as the growth and coarsening of precipitates,
micro-crack formation, and their coalescence. Weibull distribution-based analysis established its
potential as an alternative method for predicting the failure probability and life of power plant components
under creep deformation from the NLU measurements
The Synergistic Effects of Boron and Impression Creep Testing during Paced Controlling of Temperature for P91 Steels
No full textThis article induces quadruple knowledge on the effects of 100 ppm (P91B) and 22 ppm (P91) boron in as-received 9Cr steels in normalized and tempered conditions (NT) and impression crept conditions (ICC). Herein, impression creep testing is improved through paced temperature to fast evaluate creep performance. P91B performs the utmost by advancing activation energy and 30% better creep life, leading to the same targeted creep life at 574 degrees C as P91 at 550 degrees C. Further, it incisively discusses variations in microstructure, precipitate size, geometrically necessary dislocations (GNDs), pseudo-rocking curve, grain size (GS), several types of grain boundaries (GBs), effective GB energy, and elastic stiffness. Novel phenomenological mechanisms like GB hardening/softening; antithetical mechanisms; boron-dependent mosaicity; grain refinement/fragmentation/coarsening/homogenization; interaction among various types of GBs, triggering re/degeneration of dislocations and sigma boundaries as sigma reactions; super-continuous and geometric dynamic recrystallizations; enhanced creep immunity of like-oriented GBs than unlike oriented GBs; primary/secondary recrystallization; specialness; boron/NT/ICC-dependent stiffness; high stiffness is dependent on low GNDs and big GS, and vice versa is observed. The synergistic effects of [100 ppm boron in NT/ICC] and ICC in the manifestation of 22/100 ppm boron are ascertained. However, dependency [proportionally and antithetically] and independency of GB character on creep-microstructural reciprocity discourse and converse into the mathematical relationship
A comprehensive study on the through-process Goss texture evolution in Fe-3.78 wt.%Si grain-oriented electrical steel
No full textCold-rolled grain-oriented steel is used in transformer cores due to its superior magnetic properties. Large Goss-oriented grains develop after the final secondary recrystallization providing low hysteresis loss. The present study represents the development of Goss orientation after each processing stage of Fe-3.78 wt% Si steel with the help of electron backscatter diffraction and x-ray diffraction techniques. The Goss-oriented grains developed during hot rolling and hot band annealing did not remain stable in cold rolling. On the other hand, shear bands developed inside {111} component of gamma-fiber texture during cold rolling. Partial recrystallization of the cold rolled sheet revealed that Goss-oriented grains started evolving inside the shear bands of {111} oriented grains. Intermediate annealing between cold rolling passes was found to be not essential to achieve Goss orientation in primary recrystallization. The optimum primary recrystallization temperature was in between 923 and 948 K where a significant amount of Goss oriented grains were present. Further, secondary recrystallization was attempted at different temperatures between 1173 and 1473 K. Grain boundary curvature of Goss-oriented grains and all other grains after both primary and secondary recrystallization was studied. Despite the percentage of convex boundaries surrounding Goss-oriented grains being found slightly higher than that around other grains, it was insufficient to cause abnormal grain growth
Statistical analysis and optimization studies on recovery of carbon from steel plant sludge
No full textSteel-making industries that produce sludge as a by-product in their operations contain valuable mineral phases and carbon which can be recovered for primary and secondary usage. The present study aims to recover carbon values from the sludge, adopting flotation technique by altering the surface hydrophobicity of carbon values and optimizing its process parameters for effective separation. Laboratory scale studies were carried out in a D12 Denver flotation cell using a laboratory-synthesized flotation reagent as the collector for carbon recovery and Methyl Isobutyl Carbinol (MIBC) as the frother. The experimental study was statistically designed using the Taguchi method with three input variables, i.e., frother dosage, cell revolutions per minute (rpm), and collector dosage at mixed levels for process parameter optimization and for interpretation of the importance of process parameters on the mean and variation of responses. Experimental designing and statistical analysis were used to study the effects of input parameters on outputs and determine the order of significance. Among L18 (2^1*3^2) orthogonal array experiments performed, the one with operating conditions at 1400 rotations per minute (rpm) of the cell, frother dosage of 54 g per tonne (gpt), and collector dosage of 3400 g per tonne (gpt) of feed, 83.05% carbon recovery was optimally obtained. Based on the flotation experimental test results, one-way analysis of variance (ANOVA) was used to predict the order of significance of three input variables for each response variable namely, carbon grade and carbon recovery. The order of significance for the response parameter, carbon recovery, was observed to be in the order of Collector dosage > Frother dosage > Cell rpm indicating the impact of the laboratory-synthesized collector on recovering the carbon values from the sludge
Multi-component Zr based biocompatible alloys with modulus ≤50 GPa and density ~2.8 gm/cm3 for biomedical application
No full textOrthopaedic implants are manufactured to replace damaged bone or joint. These implants are intended to treat the skeletal deformities and restore the normal skeletal function. The demand for orthopaedic implants has been increased tremendously, for the ageing population, with the increasing risk of osteoporosis, osteoarthritis. The Major segments in implant dominants are the knee, spine, hip, dental and trauma incidents. According to Allied market research, a UK based company (https://www.alliedmarketresearch.com/business-and-market-research) had revealed the orthopaedic implants market was around 66,636 million by 2025. In India, Hospaccx Healthcare Business Consultancy is one of the leading Healthcare and Hospital Consultancy (https://hhbc.in/orthopaedic-market-scenario-of-india/ ) has published that Indian Orthopedic market is around USD 450 million in 2018 and the market is growing at over 30% per year which is considered to be the most dynamic sector in India. In recent years the Government of India has implemented several policy measures to address the challenges of medical devices industry. Among them, R&D related important point is ‘Make in India’ initiative for promoting indigenous manufacturing where medical devices are one of the categories. ‘Swastha Bharat’ is for health mission. Similarly, different R&D funding agencies of Government of India like Department of Bio-Technology (DBT) has chosen its thrust area as ‘Biomedical Engineering’, Department of Science and Technology (DST) has introduced Biomedical Device and Technology Development Program (BDTD). CSIR in its R&D activities has marked healthcare research as one of the niche areas.
Indian Government has also implemented a plan to reduce the price of surgery and now with the policy standard and widely used implants such as (i) cobalt-chromium (Co-Cr) in knee replacement surgery which is costing Rs 54,720 against the earlier cost of Rs 1,58,324 (ii) The price of special metals like titanium and oxidised zirconium (Oxinum) has been slashed by almost 70%, to Rs 76,600 from Rs 2.49 lakhs. (iii) In this plan it keeps a provision for revised knee replacement, if the primary replacement fails, prices of next implants will be cut by 59%.
Here, it can be referred that Co-Cr alloy contains nickel as an alloying element and nickel has a carcinogenic effect. The Co-Cr, Steel 316L, Ti and Ti-alloys which are generally used as common implant materials have very high mechanical properties. The modulus of elasticity lies in the range of (100-260) GPa while in comparison cortical bone is in the range of (10-30) GPa. The dissimilarity in mechanical property between bone and implant creates a stress shielding effect which spoils the bone in and around the periphery of the implant and sometimes further implants replacement is required.
Therefore, the proposed project deals with Zr-Ti-Ca-Si-Fe alloy system having a targeted modulus of elasticity near to that of bone and will be made with biocompatible constituent alloying elements to avoid any carcinogenic effect in the human body
Study on Flotation of Sillimanite Using Plant-Based Collector
Get PDFIn India, the heavy mineral beach sand carry minerals like ilmenite, garnet, rutile, monazite, sillimanite, and zircon. The west coast of Kerala, the east coast from Tamil Nadu to Odisha contains heavy mineral (ilmenite) rich beach sand deposits. These ilmenite samples of Indian origin has 50-60% ofTiO2 and is most suited for beneficiation by different processes. Also minerals such as monazite, sillimanite, and zircon are present in inland red Teri sands, apart from heavy mineral beach sands and has high potential for beneficiation. The conducting and magnetic minerals are separated first, leaving behind the non-conducting and non-magnetic sillimanite along with quartz in the processing of heavies in beach sand. The placer minerals of 348 Million tons (Mt) ilmenite, 107 Mt garnet, 21 Mt zircon, 18 Mt monazite, and 130 Mt Sillimanite are present in Indian resources. About 35% of world resources are contributed from India. The heavy mineral sands are basically sedimentary deposits of dense minerals which pile up with sand, silt, and in association with clay along the coastal line, leading to economic concentrations of these heavy minerals [1-5]. The conducting and magnetic minerals are separated first, leaving behind the non-conducting and non-magnetic sillimanite along with quartz in the processing of heavies in beach sand. Sillimanite, an important mineral for refractory application, is mainly recovered by flotation technique from its associated major gangue mineral, quartz by imparting selective surface hydrophobicity on sillimanite using a suitable collector. Sillimanite is a non-conducting and non-magnetic mineral and hence flotation technique was of valuable minerals from its accompanying gangue minerals. Flotation process have been effectively used for fines and size of the sillimanite mineral present in the heavy mineral beach sand is most appropriate to be processed by flotation. In any separation process based on flotation, the flotation reagents added in order to modify/enhance the surface hydrophobic nature of the minerals intended to be separated and hence the appropriate selection of reagent plays a vital role in the efficiency of the flotation technique. Apart from the reagent selection, the dosage of the reagents added in the flotation circuits needs to be optimized for the required grade and recovery. Flotation studies on sillimanite by flotation column on Odisha sands were carried out using oleic acid as collector [6-14]. Recovery of sillimanite by flotation tree analysis method and conventional flotation technique from the non-magnetic product of red sediments were also studied. Also, some investigation on flotation of sillimanite at acidic pH were reported.
In this work, one such Indian beach placer sample has been attempted for beneficiation using flotation method. In preliminary flotation studies, pH and depressant dosage were varied to establish the optimized process criteria. lypes of collectors used for flotation studies are oleic acid and plant-based collector SFA. Flotation of sillimanite sample was optimized by studying various process parameters. Sillimanite feed sample, collectors, and concentrate obtained from optimized set have been characterized using X-ray diffraction (XRD) and Fourier-transform infrared (FfIR) spectroscopy
A Comparative Study on Flotation of Coal Using Eco-Friendly Single Reagent and Conventional Dual-Reagent System
Get PDFCoal, an organic sedimentary rock, is the backbone on which electricity generation and steel making rest. Coal contains mainly carbon, hydrogen, oxygen, nitrogen and sulphur as well as trace amounts of other elements, including the mineral matter that refers to the inorganic constituents of coal [1]. Mineral matter is the principal source of the elements that make up the ash content while the organic matter or the coal macerals contributes to carbon constituents. Most of the high ash coals are subjected to beneficiation for reducing the ash levels so as to make them suitable for various applications. Coking coal or metallurgical coal are coals when baked in absence of air, form a grey, hard, carbonaceous porous residue called 'coke'. These are mainly used for iron and steel manufacturing. Generally coking coals are a part of the bituminous group. While non-coking coals are mainly used for power generation. The mined coal is associated with inorganic impurities during its formation that forms the ash residue in coal which is undesirable for effective utilization of coal for many applications. The high-rank coal with high carbon and less ash content is depleting rapidly. As high-rank coal resources are running out due to the rise in energy demand and steel production, it is therefore imperative to use low-rank, oxidized coal to meet the increasing need for coal [2, 3]. Hence, the need for utilizing low-rank coals with low carbon and high ash is of utmost importance. As these low-rank coal can be effectively utilized after cleaning or washing in order to reduce the ash-forming mineral phases and thereby improving the carbon content of the coal for further suitable utilization. A fine coal washery losses ten times as much high-quality coal as a coarse coal washery. Recovering good quality fines will improve the economics of coal washery [4]. Generally, coal washing involves crushing and screening of Run-of-Mine (ROM) coal into smaller fractions, separating the gangue and mineral matter by using physical separation methods such as dense media separation/heavy media separation (HMS) or physico-chemical process, called froth flotation. As flotation process is based on differences in the ability of air bubbles to selectively attach to specific mineral surfaces in a mineral-water slurry and float to the top based on their degree of hydrophobicity [5-7]. Froth flotation is one of the beneficiation methods in fine coal washing by exploiting the surface hydrophobicity difference between coal macerals that are naturally hydrophobic and its associated ash forming minerals impurities that are mostly hydrophilic in nature. This naturally hydrophobic surface property of coal surface provides a high response while processed by flotation as it is a surfacephenomenon-based separation technique. Hence, coal particles have a natural affinity toward air bubbles [8, 9] as they are naturally hydrophobic
Efficacy of Pilot Scale Batac Jig on LVC Coal Utilization for Coke Making
No full textThe focus of present research is to see the effectiveness of Pilot scale Batac jig for beneficiation of coarse (- 13 + 1 mm) low volatile coking coal from Jharia through a series experimentation wherein appropriate diverse process parameters were exploited for definitive study. The feed coal properties were measured in terms of proximate and ultimate analysis. The gross calorific value was observed as 5784 kcal/kg. The performance of jigging process observed layer wise, evidenced that the stroke length and air pressure of the process parameters were impressively provoking generation in potency of the process. The jigging experiments revealed that 24.6% ash content of concentrate was achieved with 76% yield from the feed ash content of 32.5% in top layers under optimum process conditions, whereas bottom layer contained 57.4% ash as the final reject. The jig product is promising and practicable for assured usage as blendable coking coal for making metallurgical coke