Chandraambhorn, Walairat

Preferred name

Alternative Name

Chandra-Ambhorn, Walairat

Chandra-ambhorn, Walairat

Chandra-Ambhorn, W.

Main Affiliation

School of Engineering

walairat.ch@kmitl.ac.th

Now showing 1 - 10 of 10

Some of the metrics are blocked by your
consent settings
Reduction of chromium volatilisation from stainless steel interconnector of solid oxide electrochemical devices by controlled preoxidation
(2016-05-01)
Wongpromrat, Wichitra
;
Berthomé, Grégory
;
Parry, Valérie
;
Chandra-ambhorn, Somrerk
;
Chandra-ambhorn, Walairat
Some of the metrics are blocked by your
consent settings
Characterisation and pickling behaviour of thermal oxide scale on low carbon steel produced from a thin slab
(2011-01-01)
Chandra-Ambhorn, Somrerk
;
Somphakdee, Tanongsak
;
Chandra-Ambhorn, Walairat
Thin slab interested in this work was the one with the thickness of ca. 50 mm and mainly made from recycled steel. Chemical composition of the studied steel strip produced from such slab was Fe with 0.077 wt% C, 0.233 wt% Mn, 0.191 wt% Si, 0.159 wt% Cu and 0.052 wt% Ni. Scale retained on that steel after hot rolling was studied. The hot-rolled sample was pickled in 10%v/v HCl aqueous solution at 80 °C. Weight loss and relative XRD peaks of hematite-per-iron and magnetite-per-iron were measured at different pickling periods of time. It was observed that the as-received scale was crack-free. Hematite-and-iron ratio approached zero at the pickling time of 3 seconds. Magnetite-per-iron ratio gradually decreased with increased pickling time and approached zero later. These results indicated that pickling solution attacked the outermost hematite layer resulting in removing of this layer first. Sublayers of scale consisting of magnetite were completely pickled later. Pickling behaviour was not merely volumetric since scale was crack-free. Mechanical adhesion of scale on steel substrate was additionally investigated by tensile test to help characterise the oxide scale. © (2011) Trans Tech Publications.
Some of the metrics are blocked by your
consent settings
Optimisation of metallic interconnects for hydrogen production by high temperature water vapour electrolysis
(2012-01-01)
Ardigo, M. R.
;
Parry, V.
;
Popa, I.
;
Chevalier, S.
;
Chandra-Ambhorn, W.
For economical and environmental reasons, hydrogen is considered as a major energetic vector for the future. Hydrogen production via high temperature water vapour electrolysis (HTE) is a promising technology. A major technical difficulty related to high temperature water vapour electrolysis is the development of interconnects working efficiently for a long period. Working temperature of 800°C enables the use of metallic materials as interconnects. Chromia forming alloys are among the best candidates. The interconnect material chosen in the present study is a ferritic stainless steel with 18% chromium content. High temperature corrosion resistance and electrical conductivity of the alloy was tested in both cathode (H<inf>2</inf>/H<inf>2</inf>O) and anode (O<inf>2</inf>/H<inf>2</inf>O) atmospheres. Corrosion products were then characterized by SEM-EDX and XRD. Moreover chromium evaporation measurements were carried out under anode atmosphere. © (2012) Trans Tech Publications.
Some of the metrics are blocked by your
consent settings
Arsenic adsorption using the adsorbent synthesised from oyster shell
(2017-01-01)
Khownpurk, Pichnipa
;
Wongpromrat, Wichitra
;
Chandra-Ambhorn, Walairat
Ground oyster shells were calcined and used as an adsorbent to remove As (III) from contaminated water. Adsorption experiment was performed by batch tests. The effect of pH on the adsorption performance was investigated. The result showed that at the initial concentration of 100 mg/L, over the pH range of 5-11, the highest efficiency was obtained at pH 11. The experimental data better correlated with pseudo-second order model. The maximum adsorption capacity (q<inf>m</inf>) of approximately 195.5 mg/g was obtained at pH 11.
Some of the metrics are blocked by your
consent settings
Preparation and characterization of oyster shell powder-treated rice husk ash adsorbent pellet for As(III) removal
(2018-08-14)
Khownpurk, Pichnipa
;
Chandra-Ambhorn, Walairat
The adsorbent pellet for As(III) removal was prepared from ground oyster shell and rice husk ash. The effects of particle size of oyster shell powder (OS) and the ratio between the OS and Treated rice husk ash (TRHA) on the stability of the adsorbent pellet were studied. The adsorbent pellet was characterized by XRD, XRF and SEM. The solubility and As(III) adsorption tests were performed. The results showed that the adsorbent pellet prepared from OS size <106 μm with OS:TRHA ratio of 0.7:0.3 could provide As(III) maximum adsorption capacity of approximately 26.20 mg/g. Furthermore, the XRD and SEM results indicated that the adsorbent pellet could consist of two parts i.e. CaO that could adsorb As(III) in the form of Ca-As-O and the CaSiO<inf>3</inf> and C-S-H compounds which behaved as a binder to bind the precursor powders to be stable adsorbent pellet without cracking.
Some of the metrics are blocked by your
consent settings
Advanced microstructural investigations of AISI 441 early stage oxidation in wet atmosphere
(2017-01-01)
Wongpromrat, Wichitra
;
Parry, Valérie
;
Chandra-Ambhorn, Walairat
;
Chandra-Ambhorn, Somrerk
;
Galerie, Alain
AISI 441 ferritic stainless steel is a good candidate for metallic interconnects in solid oxide fuel cells (SOFCs). The minor elements Ti and Nb are used to stabilize the ferritic matrix and also to reduce creep by a combination of solid solution strengthening and precipitation of intermetallic Laves phase particles along the grain boundaries. However their influence on the oxidation behavior is not well understood. This study focuses on the early stages oxidation (from 4 to 24 h) at 800°C of AISI 441 under 5% H<inf>2</inf>O in O<inf>2</inf>. A relatively smooth micro-crystallized oxide scale and Ti, Nb containing nodules are observed. The internal microstructure of these objects is studied by FIB tomography which allows computing cross sectional views in any direction of interest. FIB study reveals a complex microstructure and a development strongly linked to the presence of niobium and/or titanium in the substrate.
Some of the metrics are blocked by your
consent settings
Possible connection between nodule development and presence of niobium and/or titanium during short time thermal oxidation of AISI 441 stainless steel in wet atmosphere
(2015-01-01)
Wongpromrat, W.
;
Parry, V.
;
Charlot, F.
;
Crisci, A.
;
Latu-Romain, L.
AISI 441 ferritic stainless steel is a good candidate for metallic interconnects of solid oxide fuel cells (SOFCs). In this alloy, the minor elements Ti and Nb are used to stabilise the ferritic structure but their influence on steel durability is not well understood. This study focuses on the early stages of oxidation (24 h) at 800°C of AISI 441 under 5%H<inf>2</inf>O in O<inf>2</inf> following the cathodic SOFCs conditions. The typical duplex oxide scale, composed of a (Mn,Cr)<inf>3</inf>O<inf>4</inf> spinel top layer and a Cr<inf>2</inf>O<inf>3</inf> rich sublayer is observed, with oxide nodules growing in places. These objects, in the micrometre range in size, are studied by FIB tomography. The analyses reveal a complex structure and a development strongly linked to the presence of niobium and/or titanium compound(s) in the subjacent substrate.
Some of the metrics are blocked by your
consent settings
Chromium vaporisation from AISI 441 stainless steel oxidised in humidified oxygen
(2013-06-01)
Wongpromrat, Wichitra
;
Thaikan, Harit
;
Chandra-Ambhorn, Walairat
;
Chandra-Ambhorn, Somrerk
Chromium vaporisation from chromia-forming alloys when exposed to high temperatures can deteriorate the protective property of oxide scale. This problem affects the lifetime of solid oxide fuel cells and solid oxide electrolysers using chromia-forming alloys as interconnectors. In this work, AISI 441, a commercial grade stainless steel which chromium vaporisation investigation has not been reported so far, was chosen for study. Chromium vaporisation rates of bare AISI 441 and AISI 430 and AISI 441 and AISI 430 coated with Mn-Co spinel by electroplating method were measured in an atmosphere of 5 % H<inf>2</inf>O in O<inf>2</inf> over the temperature range of 650-900 C with the linear velocity of the humidified oxygen stream varied in the range of 0.8-3.0 cm s<sup>-1</sup>. For uncoated samples, AISI 441 showed a lower chromium vaporisation rate in comparison with that of AISI 430. Mn-Co spinel coating could reduce the chromium vaporisation rate from AISI 430 surface. However, on the contrary, the Mn-Co spinel coating could not only fail to suppress the chromium vaporisation, but it also promoted the chromium vaporisation from AISI 441 surface by 2 times. © 2013 Springer Science+Business Media New York.
Some of the metrics are blocked by your
consent settings
Removal of As(III) from aqueous solution by the oyster shell powder–treated rice husk ash composite (OS-TRHA) pellet
(2019-07-04)
Khownpurk, Pichnipa
;
Chandra-Ambhorn, Walairat
OS-TRHA pellets prepared from oyster shell (OS) powder and treated rice husk ash (TRHA) were used as the adsorbent for arsenite (As(III)) removal from contaminated water. The effect of the OS:TRHA ratio on As(III) removal performance was investigated via batch tests. The most appropriate ratio of OS and TRHA for OS-TRHA pellet preparation was 0.7:0.3 since it provided the acceptable As(III) adsorption capacity of about 26.2 mg g<sup>−1</sup> without cracking. The OS-TRHA pellets before and after As(III) adsorption tests were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The mechanism of As(III) adsorption by OS-TRHA pellets was proposed. The experimental data correlated with the pseudo-second-order adsorption rate, and the adsorption behavior was better described by the Langmuir adsorption isotherm. The results of XRD, SEM, As(III) adsorption tests and calculation based on the Ca balance indicated that 25 wt% of OS-TRHA pellets was CaO that could react with As(III) and formed Ca-As-O (CaHAsO<inf>3</inf>) on the surface of the OS-TRHA pellets, while the other 75 wt% of OS-TRHA pellets was composed of CaSiO<inf>3</inf> and C-S-H compounds which bound the precursor powders into stable pellets without cracking.
Some of the metrics are blocked by your
consent settings
Morpho-chemical investigations and thermodynamic study of Nb-rich passive nodules grown on AISI 441 oxidized in wet atmosphere
(2018-08-15)
Parry, Valérie
;
Wongpromrat, Wichitra
;
Latu-Romain, Laurence
;
Pascal, Céline
;
Chandra-ambhorn, Walairat
AISI 441 sheets were oxidized from 4 to 24 h at 800 °C in wet atmosphere. Micrometric oxide nodules containing Ti, Nb, Cr and Mn were observed to form on the passive scale. The internal microstructure of these objects was investigated using STEM–EDX and FIB-SEM tomography. Experimental results reveal a complex microstructure linked with the presence of Si and Nb and their competition for interfacial oxidation. Eventually, the chemical compositions of the nodule and of the oxidation affected zone in the nodule vicinity are discussed in relation with thermodynamic calculations investigating the stability of the different oxides.

Chandraambhorn, Walairat

Filters

Settings

Sort By

Results per page