Hot corrosion behaviour of Super 304H for marine applications at elevated temperatures

2017 ◽  
Vol 64 (5) ◽  
pp. 508-514 ◽  
Author(s):  
M. Adam Khan ◽  
S. Sundarrajan ◽  
S. Natarajan
Keyword(s):  
Hot Corrosion ◽  
Elevated Temperatures ◽  
Corrosion Behaviour ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Salt Mixture ◽  
Content Type ◽  
X Ray ◽  
Different Temperatures ◽  
Marine Applications

Purpose The aim of this paper is to study the hot corrosion behaviour of super 304H stainless steel for marine applications. Design/methodology/approach The investigation was carried out with three different combinations of salt mixture (Na2SO4, NaCl and V2O5) at two different temperatures (800 and 900°C). Findings The spalling and growth of oxide layer was observed more with the presence of V2O5 in the salt mixture at 900°C during experimentation than what was observed in 800°C. The mass change per unit area is calculated to study the corrosion kinetics and also the influence of salt mixture. Further, the samples are analysed through materials characterisation techniques using optical image, scanning electron microscope (SEM), energy dispersive X-ray (EDAX) and X-ray diffraction (XRD) analysis. The presence of V2O5 in the salt mixture was the most important influencing species for accelerating hot corrosion. Originality/value SEM, EDAX and XRD analysis confirmed the formation of Fe2O3 and Cr2O3 at 900°C showing contribution in corrosion protection.

High temperature corrosion behaviour of aluminised FC 25 cast iron using pack cementation

2019 ◽  
Vol 66 (2) ◽  
pp. 236-241 ◽  
Author(s):  
Somrerk Chandra-Ambhorn ◽  
Neramit Krasaelom ◽  
Tummaporn Thublaor ◽  
Sirichai Leelachao
Keyword(s):  
Cast Iron ◽  
High Temperature ◽  
Corrosion Behaviour ◽  
Mass Gain ◽  
High Temperature Corrosion ◽  
Pack Cementation ◽  
X Ray Diffraction ◽  
Content Type ◽  
X Ray ◽  
Seat Insert

Purpose This study aims to apply the pack cementation to develop the Fe-Al layers on the surface of FC 25 cast iron in order to increase the high-temperature corrosion resistance of the alloy. Design/methodology/approach Pack cementation was applied on the surface of FC 25 cast iron at 1,050°C. The bare and aluminised alloys were subjected to the oxidation test in 20 per cent O2-N2 at 850 °C. Scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy and X-ray diffraction (XRD) were used for characterisation. Findings The layers of pack cementation consisted of Fe2Al5, FeAl2 and FeAl, and solid solution alloyed with Al. The oxidation kinetics of the bare cast iron was parabolic. Mass gain of the aluminised cast iron was significantly decreased compared with that of the bare cast iron. This was because of the protective alumina formation on the aluminised alloy surface. Al in the Fe–Al layer also tended to be homogenised during oxidation. Originality/value Even though the aluminising of alloys was extensively studied, the application of that process to the FC 25 cast iron grade was originally developed in this work. The significantly reduced mass gain of the aluminised FC 25 cast iron makes the studied alloy be promising for the use as a valve seat insert in an agricultural single-cylinder four-stroke engine, which might be run by using a relatively cheaper fuel, i.e. LPG, but as a consequence requires the higher oxidation resistance of the engine parts.

Microstructural and Corrosion Studies by Immersion in 3.5% NaCl Solution on Aged Mg-9Al-1Zn-XCa Alloy

2019 ◽  
Vol 969 ◽  
pp. 93-97
Author(s):  
S. Manivannan ◽  
B. Narenthiran ◽  
A. Sivanantham ◽  
S.P. Kumaresh Babu
Keyword(s):  
Corrosion Behaviour ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
Corrosion Attack ◽  
X Ray ◽  
Α Phase ◽  
Corrosion Studies ◽  
Different Temperatures ◽  
Xrd Techniques ◽  
Scanning Electron

The experimatal alloys were aged at different temperatures of 180°C, 200°C, 220°C, and 240º C with calcium addition levels of (X=0.5, 1, 1.5, 2%) on Mg-6Al-1Zn-XCa alloy were investigated in 3.5% NaCl solution. All the experimatal alloys were immersed in 3.5% NaCl solutions and the resulted surface were analyzed to study the corrosion behaviour and its surface topography by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersed spectroscopy (EDS) and X-ray diffraction (XRD) techniques. The result shows that corrosion attack occurred predominantly on ß phase and α phase exhibit relatively minor corrosion. In addition to that the increased aging temperature coarsens the intermetallic as well as α- Mg grains, which shows adverse effect to corrosion resistances and the best result were obtained at composition of 0.5wt.% Ca aged at 200°C.

scholarly journals Chlorapatite Derived from Fish Scales

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1129
Author(s):  
Luyara de Almeida Cavalcante ◽  
Laís Sibaldo Ribeiro ◽  
Mitsuo Lopes Takeno ◽  
Pedro Tupa Pandava Aum ◽  
Yanne Katiussy Pereira Gurgel Aum ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Xrd Analysis ◽  
Fish Scales ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
X Ray ◽  
Arapaima Gigas ◽  
Treated Fish ◽  
Different Temperatures ◽  
Increasing Temperature

The present work demonstrates the production of chlorapatite (ClAp) through thermal decomposition of chemically treated fish scales, originating from an Amazon fish species (Arapaima gigas). The scales were treated with hydrochloric acid (HCl) solution for deproteinization. Afterwards, the solution was neutralized by sodium hydroxide (NaOH) treatment to obtain an apatite-rich slurry. The heat treatment was carried out at different temperatures including 600 °C, 800 °C, and 1000 °C. The powders obtained were characterized through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM). The XRD analysis and FTIR spectra confirmed the incorporation of chlorine into the apatite structure. The FTIR results showed absorption bands relative to the OH–, PO43− functional groups which are a characteristic of chlorapatite. Moreover, the intensity of the OH–Cl elongation could be observed. Chlorapatite Ca5(PO4)3Cl, NaCl, and NaCaPO4 phases were identified, achieving up to 87.4 wt% for ClAp. The SEM observations show that with increasing temperature, the ClAp obtained consists of slightly larger, more crystalline grains. Furthermore, the grains ranged in size, between 1-5 μm and ClAp1000 sample recorded crystallinity of 84.27%. ClAp and NaCaPO4 can be used in electronics as phosphor materials due to their luminescence and biomedical applications.

Study of the Hydration Process of Synthetic Preparation of Ettringite by Direct Addition of Aluminum Sulfate and Calcium Hydroxide

2018 ◽  
Vol 276 ◽  
pp. 60-65
Author(s):  
Marcela Fridrichová ◽  
Dominik Gazdič ◽  
Jana Mokrá ◽  
Karel Dvořák
Keyword(s):  
Calcium Hydroxide ◽  
Aluminum Sulfate ◽  
Xrd Analysis ◽  
Standard Laboratory ◽  
X Ray Diffraction ◽  
X Ray ◽  
Saturated Water ◽  
Direct Addition ◽  
Different Temperatures ◽  
The Stability

The stability of ettringite as high-watery mineral is highly dependent on the ambient temperature. Under standard laboratory conditions, onset of decomposition of this phase occurs at temperature of 80°C already and the theoretical temperature of the complete decomposition of ettringite is 180°C. Ettringite decomposition can occur at significantly different temperatures under humidity conditions other than the laboratory ones. Within the work verification of the possibility of synthetic preparation of ettringite by direct addition of aluminum sulfate, Al2(SO4)3·18H2O, and calcium hydroxide, Ca (OH)2, as an alternative method to the yeelimite hydration procedure was carried out. The stability of the resulting systems was examined in two different environments, namely in a laboratory environment and the environment of saturated water vapour. The phase composition of the samples was determined by X-ray diffraction (XRD) analysis, thermal analysis and scanning electron microscopy (SEM).

TEMPERATURE EFFECT ON STRUCTURAL AND ELECTRONIC PROPERTIES OF ZINC OXIDE NANOWIRES SYNTHESIZED BY CARBOTHERMAL EVAPORATION METHOD

2012 ◽  
Vol 11 (05) ◽  
pp. 1250032 ◽  
Author(s):  
MOHAMMAD ORVATINIA ◽  
ROGHAYEH IMANI
Keyword(s):  
Zinc Oxide ◽  
Grain Boundary ◽  
Elevated Temperatures ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Structural And Electronic Properties ◽  
Different Temperatures ◽  
Sem Micrograph

Zinc Oxide ( ZnO ) nanowires were synthesized on the Si substrates by carbothermal evaporation of ZnO + C at elevated temperatures. The syntheses were carried out at different temperatures from 750°C to 950°C. Characterizations of layers were performed to study the effect of synthesis temperature on morphology, crystal structure and electrical behavior of fabricated nanowires. The physical characterization was performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDAX) methods. SEM micrograph of layers revealed that the samples grown at the lower temperatures have better quality. However, below 800°C the growth of nanowires was stopped. So the 800°C was concluded to be the optimum temperature for growth of high quality nanowires by proposed system. By recording the conductivity variations as a function of inverse temperature, 1/T, the semiconductor property of the samples was verified. It is demonstrated that two distinct factors affect the electrical conductivity of layers, which are due to the bulk and grain boundary. We experimentally proved that the activation energy corresponding to grain boundary is higher than that of the bulk. As another result we have established for the first time that by increasing synthesis temperatures, both activation energies shift to higher values.

Joining and characterization of SS-430 using microwave hybrid heating technique

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nalin Somani ◽  
Navjot Singh ◽  
Nitin Kumar Gupta
Keyword(s):  
Elevated Temperatures ◽  
Inert Atmosphere ◽  
X Ray Diffraction ◽  
Content Type ◽  
Hybrid Heating ◽  
X Ray ◽  
Microwave Hybrid Heating ◽  
Metallurgical Study ◽  
Worn Surface

Purpose The purpose of this paper is to based upon the joining and characterization (mechanical and metallurgical) of ferritic stainless steel (SS)-430 using a microwave hybrid heating (MHH) phenomenon. Design/methodology/approach The preliminary experiments were conducted using nickel-based powder as interface material using a domestic microwave oven at a frequency of 2.45 GHz and 900 W power for 720 s. The processed joint was metallurgically characterized by means of X-ray diffraction, Energy-dispersive X-ray spectroscopy and Field emission scanning electron microscopy. Mechanical characterization was done by means of tensile and Vickers’ microhardness testing to check the hardness and strength of the joint. Findings The metallurgical study revealed that the microstructure and formation of numerous phases of Fe2Si3 accompanied by chromium and nickel carbides. The average hardness of 359 Hv at the center of the joint and 637 Hv around the boundaries of the joint was observed. The tensile strength of the joint was observed to 471 MPa with an elongation of 9.02%. The worn surface of the joint signifies the presence of plastic deformation and it was limited due to the presence of harder phases such as Ni3Si and Ni3C. Research limitations/implications The concept of microwave joining of metals is a very challenging task as the temperature can not be controlled in the inert atmosphere of the microwave. It has been also observed that at certain elevated temperatures, the material starts absorbing the microwaves; which is unknown. So, a more intensive study is required to overcome these kinds of limitations. Practical implications MHH technique can be used to process different materials such as ceramics, composites and polymers. SS-430 joined by microwave heating is highly corrosion resistive and has wide applications in refrigerators cabinet panels, dishwasher linings, chimney liners, lashing wires, etc. Originality/value As of the author’s best knowledge, no work has been reported on the joining of SS-430 which has huge potential in the industries. Also, no work has been reported on the characterization of microwave joined SS-430.

XRD analysis of TRAM composed from [Sb2Te3/GeTe] superlattice film and its switching characteristics

2015 ◽  
Vol 1729 ◽  
pp. 41-45
Author(s):  
T. Ohyanagi ◽  
M. Kitamura ◽  
S. Kato ◽  
M. Araidai ◽  
N. Takaura ◽  
...  
Keyword(s):  
Random Access ◽  
Xrd Analysis ◽  
Electrical Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Switching Characteristics

ABSTRACTWe studied GeTe structures in topological switching random access memories (TRAMs) with a [GeTe/Sb2Te3] superlattice by using X-ray diffraction (XRD) analysis. We examined the electrical characteristics of the TRAMs deposited at different temperatures. We found that XRD spectra differed between the films deposited at 200 and 240°C and that the differences corresponded to the differences in the GeTe sequences in the films.

Hot Corrosion Studies of HVOF-Sprayed Cr3C2-NiCr Coating on 310S Stainless Steel in an Actual Environment of a Coal Fired Boiler

2012 ◽  
Vol 585 ◽  
pp. 483-487 ◽  
Author(s):  
V.N. Shukla ◽  
R. Jayaganthan ◽  
V.K. Tewari
Keyword(s):  
Stainless Steel ◽  
Hot Corrosion ◽  
Corrosion Behaviour ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Corrosion Studies ◽  
Super Heater ◽  
Actual Environment ◽  
Cyclic Studies ◽  
The Given

The present investigation is an attempt to evaluate the hot corrosion behaviour of high velocity-oxy fuel (HVOF) sprayed Cr3C2-25 % NiCr coating on 310S stainless steel in an actual industrial environment of a coal fired boiler. The cyclic studies were performed in the super heater zone of a coal-fired boiler where the temperature was around 700±100C. Experiments were carried out for 3 cycles each of 500 hours duration followed by 1 hour cooling in air till room temperature. X-ray diffraction (XRD) analysis and field emission scanning electron microscope (FESEM, FEI, Quanta 200F Company) with EDAX Genesis software attachment were used to analyse the oxidation-erosion products. The Cr3C2-25wt% NiCr coated specimen showed good adherence to the 310S SS substrate with negligible microspalling of the scales. The Cr3C2-25wt % NiCr coating deposited on 310S stainless steel imparted better hot corrosion resistance than the uncoated one in the given environment.

Effect of Heat Treatment on the Corrosion Behaviour of a Mg-Y Alloy in Chloride Medium

2010 ◽  
Vol 636-637 ◽  
pp. 491-496 ◽  
Author(s):  
M. Carboneras ◽  
Claudio J. Múnez ◽  
Pilar Rodrigo ◽  
M. Dolores Escalera ◽  
Maria Dolores López ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Elevated Temperatures ◽  
Corrosion Behaviour ◽  
X Ray Diffraction ◽  
Chloride Medium ◽  
X Ray ◽  
Technology Applications ◽  
Mechanical Properties And Corrosion ◽  
Surface Examination

Corrosion behaviour of a Mg-Y alloy (commercial WE54) has been studied. This alloy presents excellent retention of mechanical properties and corrosion resistance at elevated temperatures, a combination of properties that can be of interest in many technology applications. To evaluate the effect of heat treatment on the corrosion resistance, WE54 samples in extruded state and after T6 heat treatment were studied. Corrosion behaviour was evaluated by electrochemical and immersion tests in 3.5 wt.% NaCl solution at room temperature and neutral pH. Surface examination was carried out by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD). It was found that corrosion resistance of the magnesium alloy WE54 in chloride medium was improved by applying the heat treatment to the material, a fact that was correlated with the developed microstructure in T6 condition.

Impact Properties of TiC/Fe at Elevated Temperatures

2010 ◽  
Vol 434-435 ◽  
pp. 113-115
Author(s):  
Yan Rong Bao ◽  
Bin Li ◽  
Zong De Liu ◽  
Zhi Jian Bao
Keyword(s):  
Fracture Surface ◽  
Impact Test ◽  
Elevated Temperatures ◽  
Impact Fracture ◽  
X Ray Diffraction ◽  
Impact Properties ◽  
X Ray ◽  
Before And After ◽  
Different Temperatures ◽  
The Impact

The impact properties of TiC-Fe composite at different temperatures prepared by SHS / PHIP technique were investigated by impact test which was conducted in air from 20°C to 100020°C. Morphology of the impact fracture surface was observed by scanning electron microscope (SEM) and phase composition before and after the impact test was analyzed with X-Ray Diffraction. The results indicate that the impact toughness of TiC-Fe composite increases significantly with the temperature increasing above 700°C, representing a minimum value at 700°C. The impact fracture of TiC-Fe composite at room temperature, 700°C, 900°C and 1000°C is mainly brittle, showing certain plasticity with morphology of dimples as the temperature increases above 700°C. A small amount of Fe2O3 exists in the fracture surface, indicating TiC-Fe composite is oxidized partially during the impact test at elevated temperatures.

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