Characterization of Cobalt Based Microwave Clad Developed on SS-355

2019 ◽  
Vol 895 ◽  
pp. 259-264
Author(s):  
Ajit M. Hebbale ◽  
M.S. Srinath

In the present work a detailed microstructural investigation of Cobalt based microwave cladding on S-355 stainless steel was carried out. The experimentations were carried out in a home based domestic microwave oven. This article clears the circumstances of clad formation during microwave hybrid heating. The solidification texture and grain structure of the developed clad scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy, and measurement of Vicker’s microhardness. Cobalt based clads developed with an approximate thickness of 1 mm without interfacial cracking. The microstructure of clad clearly illustrated excellent metallurgical bond with S-355 substrate and found dominantly fine cellular grains. Iron and cobalt were recognized inside the cells while chromium was ascertained segregated around the cell boundaries. The average microhardness of the cobalt based clad was observed in the range of 402±60 HV.

2017 ◽  
Vol 890 ◽  
pp. 356-361 ◽  
Author(s):  
Lingappa M. Shashank ◽  
M.S. Srinath ◽  
Hassan Jayaraj Amarendra

Microwave processing of bulk metallic materials is an emerging area. In the present work, brass in bulk form is melted in a modified domestic microwave oven operating at 2.45 GHz frequency. As-received and the as-cast brass are subjected to metallurgical and mechanical characterization. Specimens’ surface morphology is studied under Scanning Electron Microscope (SEM). X-Ray Diffraction (XRD) pattern shows the presence of copper oxides phase in both cast brass. Average tensile strength of brass melted using microwave oven is found higher when compared with brass melted in muffle furnace. Hardness of the as-cast brass is found to be higher than the as-received brass. However, brass cast by microwave irradiation exhibits around 2 % higher hardness than the brass cast by conventional heating. Microwave melting of brass consumed nearly six times less time compared to conventional melting.


Author(s):  
Sandeep Bansal ◽  
Dheeraj Gupta ◽  
Vivek Jain

Hydropower plants are experiencing huge revenue losses due to the failure of hydro turbines caused by cavitation. Surface modification could be a feasible solution to tackle this problem. Microwave processing of metallic materials to coat/clad has gained popularity in recent years. In the current study, microwave exposure time by analyzing susceptor temperature is optimized to get sound clads. Nickel-based and Cr3C2-reinforced clad on SS-316 substrate is developed for cavitation erosion resistance. The clads have been developed in a domestic microwave oven of 2.45 GHz and 900 W. The Ni + 30% Cr3C2 developed clad has been characterized through various standard mechanical and metallurgical techniques like X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, Vicker’s micro-hardness, porosity measurement, and flexural study. The presence of various carbide and intermetallic phases Cr2Ni3, Cr7C3, CrSi, SiO2, and FeNi3 is confirmed from the X-ray diffraction pattern. The distribution of hard carbide phases into soft matrix is confirmed from the microstructural investigation. Vicker’s microhardness study confirms the enhanced average microhardness of the clad region by 2.5 times of the substrate. The analysis of porosity shows significantly less (0.98%) porosity. The flexural study of developed clads by using three-point bending test is evaluated and flexural strength and deformation index values of developed clads of 814 ± 11.5 MPa and 2.29 × 10−4 mm N−1 respectively are observed.


1991 ◽  
Vol 239 ◽  
Author(s):  
István Bársony ◽  
Jos G.E. Klappe ◽  
Tom W. Ryan

ABSTRACTThe properties of polycrystalline silicon layers deposited by RTCVD have been studied by texture, stress and electrical analyse. The intrinsic layers intended for applications in integrated IC processing are very much textured with the preferred orientation depending on deposition temperature and atmosphere. Very low residual film stress in the order of 10 dyn/cm2 was detected, and a transition from compressive to tensile stress with increasing deposition temperature around 800°C was observed. This was associated with the development of the columnar structure by the (110) orientation becoming dominant at the expense of the (100) texture. Also the effect of post-deposition anneal ambience on the grain structure has been studied. Grain size and grain-boundary trapping in after doped layers have been evaluated in P-implanted RTA activated layers.


2019 ◽  
Vol 8 (4) ◽  
pp. 7782-7785

Single crystals of sodium para nitro phenol (SPNP) and potassium para nitro phenol (KPNP) was synthesized at room temperature by slow evaporation solution growth technique using ethanol as a solvent upto the size of 12 × 3 × 2 mm3 and 15 × 2 × 2 mm3 respectively. The grown crystals were characterized by UV- Visible, photoluminescence, Kurtz- Perry test, single crystal X-ray diffraction analysis and Vicker’s microhardness studies. Structural identification of grown crystals was done by single crystal X-ray diffraction and it shows both the crystals are belongs to triclinic crystal system. The SPNP and KPNP crystal emits green light radiation as evident from the PL measurement. The UV -Visible study revealed that the grown crystal has high transmission window with cut off wavelength of 207 nm and 208 nm respectively. And also the direct optical band gap was estimated to be 3.23 eV and 3.20 eV using Tauc’s plot. The SHG output of grown crystals was recorded by Kurtz Perry technique and it is found to be nearly five times greater than the reference KDP. The Vickers hardness test confirms the mechanical stability of the material.


2021 ◽  
Vol 54 (1) ◽  
Author(s):  
Adam Lindkvist ◽  
Haixing Fang ◽  
Dorte Juul Jensen ◽  
Yubin Zhang

Laboratory diffraction contrast tomography (LabDCT) is a recently developed technique for 3D nondestructive grain mapping using a conical polychromatic beam from a laboratory-based X-ray source. The effects of experimental parameters, including accelerating voltage, exposure time and number of projections used for reconstruction, on the characterization of the 3D grain structure in an iron sample are quantified. The experiments were conducted using a commercial X-ray tomography system, ZEISS Xradia 520 Versa, equipped with a LabDCT module; and the data analysis was performed using the software package GrainMapper3D, which produces a 3D reconstruction from binarized 2D diffraction patterns. It is found that the exposure time directly affects the background noise level and thus the ability to distinguish weak spots of small grains from the background. With the assistance of forward simulations, it is found that spots from the first three strongest {hkl} families of a large grain can be seen with as few as 30–40 projections, which is sufficient for indexing the crystallographic orientation and resolving the grain shape with a reasonably high accuracy. It is also shown that the electron current is a more important factor than the accelerating voltage to be considered for optimizing the photon numbers with energies in the range of 20–60 keV. This energy range is the most important one for diffraction of common metals, e.g. iron and aluminium. Several suggestions for optimizing LabDCT experiments and 3D volume reconstruction are finally provided.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.


Author(s):  
L. T. Germinario

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.


Author(s):  
J. H. Resau ◽  
N. Howell ◽  
S. H. Chang

Spinach grown in Texas developed “yellow spotting” on the peripheral portions of the leaves. The exact cause of the discoloration could not be determined as there was no evidence of viral or parasitic infestation of the plants and biochemical characterization of the plants did not indicate any significant differences between the yellow and green leaf portions of the spinach. The present study was undertaken using electron microscopy (EM) to determine if a micro-nutrient deficiency was the cause for the discoloration.Green leaf spinach was collected from the field and sent by express mail to the EM laboratory. The yellow and equivalent green portions of the leaves were isolated and dried in a Denton evaporator at 10-5 Torr for 24 hrs. The leaf specimens were then examined using a JEOL 100 CX analytical microscope. TEM specimens were prepared according to the methods of Trump et al.


Author(s):  
V. Serin ◽  
K. Hssein ◽  
G. Zanchi ◽  
J. Sévely

The present developments of electron energy analysis in the microscopes by E.E.L.S. allow an accurate recording of the spectra and of their different complex structures associated with the inner shell electron excitation by the incident electrons (1). Among these structures, the Extended Energy Loss Fine Structures (EXELFS) are of particular interest. They are equivalent to the well known EXAFS oscillations in X-ray absorption spectroscopy. Due to the EELS characteristic, the Fourier analysis of EXELFS oscillations appears as a promising technique for the characterization of composite materials, the major constituents of which are low Z elements. Using EXELFS, we have developed a microstructural study of carbon fibers. This analysis concerns the carbon K edge, which appears in the spectra at 285 eV. The purpose of the paper is to compare the local short range order, determined by this way in the case of Courtauld HTS and P100 ex-polyacrylonitrile carbon fibers, which are high tensile strength (HTS) and high modulus (HM) fibers respectively.


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