scholarly journals Effect of Mo Addition on the Chemical Corrosion Process of SiMo Cast Iron

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1745
Author(s):  
Marcin Stawarz ◽  
Paweł M. Nuckowski
Keyword(s):  
Cast Iron ◽  
Substrate Material ◽  
Metallographic Analysis ◽  
X Ray Diffraction ◽  
Oxide Layers ◽  
Chemical Corrosion ◽  
High Adhesion ◽  
Cyclic Operation ◽  
Mo Content ◽  
Si Content

The study was carried out to evaluate five SiMo cast iron grades and their resistance to chemical corrosion at elevated temperature. Corrosion tests were carried out under conditions of an actual cyclic operation of a retort coal-fired boiler. The duration of the study was 3840 h. The range of temperature changes during one cycle was in the range of 300–650 °C. Samples of SiMo cast iron with Si content at the level of 5% and variable Mo content in the range 0%–2.5% were used as the material for the study. The examined material was subjected to preliminary metallographic analysis using scanning microscopy and an Energy dispersive spectroscopy (EDS) system. The chemical composition was determined on the basis of a Leco spectrometer and a Leco carbon and sulfur analyzer. The examination of the oxide layer was carried out with the use of Scanning electron microscope (SEM), EDS, and X-ray diffraction (XRD) methods. It was discovered that, in the analyzed alloys, oxide layers consisting of Fe2O3, Fe3O4, SO2, and Fe2SiO4 were formed. The analyzed oxide layers were characterized by high adhesion to the substrate material, and their total thickness was about 20 μm.

scholarly journals Analysis of the Quality of Sulfomolybdenum Coatings Obtained by Electrospark Alloying Methods

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6332
Author(s):  
Oksana P. Gaponova ◽  
Bogdan Antoszewski ◽  
Viacheslav B. Tarelnyk ◽  
Piotr Kurp ◽  
Oleksandr M. Myslyvchenko ◽  
...  
Keyword(s):  
Quality Parameters ◽  
Substrate Material ◽  
Metallographic Analysis ◽  
Electrospark Alloying ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
Molybdenum Electrode ◽  
Tribological Coatings ◽  
Machine Parts

The authors of this paper have attempted to improve the quality of surface layers applied to steel elements of machine parts constituting friction couples. The main goal of the research was to investigate an electrospark alloying method process for obtaining abrasion-resistant tribological coatings containing molybdenum disulfide on a steel surface. A substance in the form of sulfur ointment with a sulfur content of 33.3% was applied on the surfaces of C22 and C40 steel specimens. In order to determine the influence of the energy parameters of ESA equipment on the quality parameters of coatings, the ESA process was carried out using a molybdenum electrode with discharge energies Wp = 0.13; Wp = 0.55; Wp = 3.4 J. The following tests were carried out on specimens with such coatings: metallographic analysis, microhardness tests, surface roughness, and local X-ray diffraction microanalysis. The experiments revealed that sulfomolybdenum coatings consist of four zones with different mechanical properties. Depending on the discharge energy and the substrate material, the hardness of these zones varies from approx. 1100 to over 10,000 MPa. Differences in the distribution of, among others, sulfur and molybdenum in the obtained coatings, as well as differences in the microstructure of the observed coatings, were observed.

scholarly journals Solidification Pattern of Si-Alloyed, Inoculated Ductile Cast Irons, Evaluated by Thermal Analysis

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 846
Author(s):  
Iuliana Stan ◽  
Denisa Anca ◽  
Stelian Stan ◽  
Iulian Riposan
Keyword(s):  
Cast Iron ◽  
Eutectic Reaction ◽  
Influencing Factor ◽  
Cooling Curve ◽  
Major Influence ◽  
Cast Irons ◽  
Minor Elements ◽  
Si Content ◽  
Si Effect ◽  
Positive Effect

The solidification cooling curve itself as well as its first derivative, and related temperatures, reported to the calculated equilibrium temperatures in stable and metastable solidification systems, are used to predict the solidification characteristics of the cast iron. Silicon, as the most representative cast iron element, and inoculation, as graphitizing metallurgical treatment, have a major influence on the transition from the liquid to the solid state. Six experimental programs are performed, with Si content typically for non-alloyed (<3.0% Si), low (3.0–3.5% Si) and medium alloyed (4.5–5.5% Si) ductile cast irons, as Si-content increasing, and inoculation simultaneous effects. Silicon is an important influencing factor, but the base and minor elements also affect the equilibrium eutectic temperatures, much more in the Fe-C-Si-Xi stable system (15–20 °C) than in the metastable system (5–10 °C), comparing with their calculation based only on a Si effect (Fe-C-Si system). The highest positive effect of inoculation is visible in non-Si alloyed cast irons (2.5% Si): 9–15 °C for the eutectic reaction and 3 to 4 times increased at the end of solidification (37–47 °C). Increased Si content decreases inoculation power to 7–9 °C for low alloying grade (up to 3.5% Si), with the lowest contribution at more than 4.5% Si (0.3–2.0 °C). 2.5–3.5% Si ductile cast irons are more sensitive to high solidification undercooling, especially at the end of solidification (but with a higher efficiency of inoculation), compared to 4.5–5.5% Si ductile cast irons, at a lower undercooling level, and at lower inoculation contribution, as well.

Preparation of β-PbO2 and β-PbO2-MnO2 Coating on Stainless Steel Substrate

2012 ◽  
Vol 490-495 ◽  
pp. 3486-3490
Author(s):  
Qiang Yu ◽  
Zhen Chen ◽  
Zhong Cheng Guo
Keyword(s):  
Stainless Steel ◽  
Mass Fraction ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Substrate Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Type ◽  
Plating Solution ◽  
Element Mass Fraction

In order to prepare a new type of anode material, stainless steel was selected as substrate material. The β-PbO2 coating on stainless steel substrate was prepared under the appropriate plating solution, and the PbO2-MnO2 coating was prepared with thermal decomposition. The crystal structure was determined by X-ray diffraction; Surface morphology was test by Scanning Electron Microscopy; the energy spectrum was used to determine element mass-fraction and the ratio of atomic number of the coatings.

Crack Resistance of Weld Seals, Hardening Methods and Composite Tools Quality

2014 ◽  
Vol 682 ◽  
pp. 431-437 ◽  
Author(s):  
V.A. Petrova ◽  
A.A. Bakanov ◽  
A.V. Walter
Keyword(s):  
Crack Resistance ◽  
Interfacial Adhesion ◽  
Thermal Spraying ◽  
Substrate Material ◽  
Metallographic Analysis ◽  
Alternating Projections ◽  
Optical Profilometry ◽  
Surface Optical ◽  
End Products ◽  
Spraying Process

The paper presents a pretreatment of the substrate material prior to the thermal spraying process. The ultrasonic finishing method allowed creation of a rolling topography comprising alternating projections and cavities, compressive stress, and increase of the number of defects on the surface. Optical profilometry and metallographic analysis allowed detecting of adhesion zones which form a strong physicochemical bond at the interface between the coating and the substrate material. This interfacial adhesion should provide a firm adhesion strength in end products.

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.

Analysis of the Structure and Abrasive Wear Resistance of White Cast Iron with Precipitates of Carbides

2013 ◽  
Vol 58 (3) ◽  
pp. 973-976 ◽  
Author(s):  
D. Kopyciński ◽  
M. Kawalec ◽  
A. Szczęsny ◽  
R. Gilewski ◽  
S. Piasny
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Abrasive Wear ◽  
Metal Matrix ◽  
White Cast Iron ◽  
Abrasive Wear Resistance ◽  
Operating Conditions ◽  
Metallographic Analysis ◽  
Abrasive Hardness ◽  
Resistance Tests

Abstract The resistance of castings to abrasive wear depends on the cast iron abrasive hardness ratio. It has been anticipated that the white cast iron structure will be changed by changing the type of metal matrix and the type of carbides present in this matrix, which will greatly expand the application area of castings under the harsh operating conditions of abrasive wear. Detailed metallographic analysis was carried out to see the structure obtained in selected types of white cast iron, i.e. with additions of chromium and vanadium. The study compares the results of abrasive wear resistance tests performed on the examined types of cast iron.

Effect of Magnetic Field on Solidification Behavior of a MnCu Damping Alloy

2018 ◽  
Vol 279 ◽  
pp. 35-43 ◽  
Author(s):  
Ze Chao Jiang ◽  
Fan Yang ◽  
Jian Lan ◽  
Qing Chao Tian ◽  
Wei Dong Xuan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Deflection Angle ◽  
Primary Dendrite ◽  
Metallographic Analysis ◽  
Coupling Mechanism ◽  
Solidification Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Variation Tendency

Preparation of Mn-Cu based damping alloy ingots coupled with strong magnetic fields shows many interesting phenomena on the solidification microstructure and the crystal lattice. In this study, modified M2052 ingots were prepared under different magnetic fields to investigate the bulk solidification behavior by using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. Metallographic analysis reveals that the deflection angle of the primary dendrite arm increases with the increase of magnetic field strength. The distribution of chemical composition characterized by X-ray Fluorescence discloses that Mn is enriched while Cu is depleted along the circumferential surface side, and the variation tendency changes from almost a level to a sloping line under applied magnetic field. High magnetic field have altered the orientation of the γ-Mn dendrites from (200) to (111), and the coupling mechanism of alloy solidification with strong magnetic field is discussed based on the experimental results.

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