Indian Institute of Technology Ropar

About: Indian Institute of Technology Ropar is a education organization based out in Ropar, India. It is known for research contribution in the topics: Catalysis & Computer science. The organization has 1014 authors who have published 2878 publications receiving 35715 citations.

Parametric Study of Slurry-Erosion of Hydroturbine Steels with and without Detonation Gun Spray Coatings using Taguchi Technique

Abstract: WC-Co-Cr coatings were deposited on some hydroturbine 13Cr4Ni and 16Cr5Ni steels by the detonation-gun spray process. An in-depth characterization of the as-sprayed coating was done using X-ray diffraction (XRD) and scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS) techniques. Microhardness and porosity measurements were also made. The coating was found to have a typical splat-like morphology with some indications of unmelted carbide particles. The XRD results showed the presence of WC as the primary phase along with W2C and Co6W6C as secondary phases. Furthermore, the slurry erosion behavior of the coatings was investigated to ascertain the usefulness of the coatings to reduce the slurry erosion of the steels. The effect of four operating factors viz. the velocity, impact angle, concentration, and particle size on the slurry erosion of coated and bare steels has been studied using a high-speed jet-type test rig. The sand used as an erodent was collected from a power plant to replicate the actual turbine conditions. It has been observed that the given cermet coating can enhance the erosion resistance of the steel. Velocity was found to be the most significant factor affecting the erosion behavior of the coating, whereas it was the erodent particle size in the case of uncoated steel. As evidenced from the SEM images, the platelet mechanism of erosion seemed to be the prominent one, causing the removal of material from the surface of the steel, whereas for the coating, the formation and interlinking of cracks resulted in the removal of material.

Progress and prospects of CZTSSe/CdS interface engineering to combat high open-circuit voltage deficit of kesterite photovoltaics: a critical review

Abstract: CZTSSe solar cells are considered to be potential and cost-effective alternative solutions to mature photovoltaic technology for meeting future energy demands. However, the current performance of CZTSSe solar cells is limited due to their high voltage deficit. The comparison of figure-of-merits of the two technologies show that CZTSSe has 62% lower open circuit voltage compared to that of 35% for CIGS, with respect to their associated band gaps. Efficient charge separation and extraction at the absorber–buffer (p–n) junction is paramount for mitigating the voltage loss and achieve high photo-conversion efficiency. The rapid progress for achieving high deliverables in CZTSSe is impeded by interface recombination, which is a consequence of poor-quality p–n junction. The inherent association of CZTSSe with secondary phases and defects due to narrow phase stability plays an unfavorable role in producing a good quality interface. The high density of interface defects, unfavorable band alignment, and structural inhomogeneities across the interface are some of the leading causes that nurture interface dominant recombination pathways. These interface-related concerns have drawn the scientific community towards interface engineering and modification of the interface to bring closer performance parity between CZTSSe and matured CIGS solar cell technology. Several approaches have attempted to develop favorable interface features that facilitate improved device performance. This work addresses the critical aspects of interface engineering of the absorber–buffer heterojunction in CZTSSe solar cells and the importance of tools that are essential to identify and eradicate the root causes of low efficiency.