G. Gunasekaran, R. Natarajan, V.S. Muralidharan, N. Palaniswamy and B.V. Appa Rao
Phosphonic acids are good complexing agents. However, they are not good as inhibitors except for a very few. Synergistic inhibition is offered in the presence of metal cations…
Abstract
Phosphonic acids are good complexing agents. However, they are not good as inhibitors except for a very few. Synergistic inhibition is offered in the presence of metal cations like Ca2+, Mg2+, Zn2+ and others in neutral media. The zinc ion is an ideal choice. The part of zinc ions are now replaced by polymers, azoles to prepare eco‐friendly inhibitor formulations. They are also used as corrosion inhibitors in concrete, coatings, rubber blends, acid cleaners, anti‐freeze coolants, etc. Discusses the various applications of phosphonic acids and their action mechanisms.
S. Rajendran, B.V. Apparao and N. Palaniswamy
The influence of a cationic surfactant, N‐cetyl‐N, N, N‐trimethyl ammonium bromide (CTAB) on the inhibition efficiency (IE) of calcium gluconate (CG) – Zn2+ system in controlling…
Abstract
The influence of a cationic surfactant, N‐cetyl‐N, N, N‐trimethyl ammonium bromide (CTAB) on the inhibition efficiency (IE) of calcium gluconate (CG) – Zn2+ system in controlling corrosion of mild steel in a neutral aqueous environment containing 60ppm Cl‐ has been evaluated by weight‐loss method. The formulation consisting of 200 ppm CG and 50ppm Zn2+ has 86 per cent IE (immersion period = three days). Addition of various concentrations of CTAB to the above system improves the IE to 99 per cent. Presence of CTAB facilitates the transport of CG and Zn2+ from the bulk of the solution to the metal surface. The nature of the protective film formed on the surface of mild steel has been analysed by FTIR and fluorescence spectra. The protective film is found to be fluorescent and to consist of iron‐CG complex, iron‐CTAB complex and Zn(OH)2.
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S. Rajendran, B.V. Apparao and N. Palaniswamy
The inhibition efficiencies of ethyl phosphonic acid (EPA) and 2‐chloroethyl phosphonic acid (2‐Cl EPA) in the presence of Zn2+, in controlling the corrosion of mild steel in a…
Abstract
The inhibition efficiencies of ethyl phosphonic acid (EPA) and 2‐chloroethyl phosphonic acid (2‐Cl EPA) in the presence of Zn2+, in controlling the corrosion of mild steel in a neutral aqueous environment containing 60ppm Cl‐ have been evaluated by weight‐loss method and compared. It is observed that 2‐Cl EPA‐Zn2+ system has more inhibition efficiency than an EPA‐Zn2+ system. It is due to the electron withdrawing power of the Cl atom and its size. The nature of the protective film formed on the surface of the metal has been analysed by X‐ray diffraction, uv‐visible reflectance and luminescence spectra.
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S. Rajendra, B.V. Apparao and N. Palaniswamy
The synergistic effect of sodium salt of 2‐chloroethyl phosphonic acid (2‐Cl EPA) and Zn2+, in controlling corrosion of carbon steel in a neutral aqueous environment containing…
Abstract
The synergistic effect of sodium salt of 2‐chloroethyl phosphonic acid (2‐Cl EPA) and Zn2+, in controlling corrosion of carbon steel in a neutral aqueous environment containing 60ppm Cl–, was evaluated by weight‐loss and electrochemical methods. A formulation consisting of 300ppm 2‐Cl EPA and 300ppm Zn2+ was observed to deliver 95 percent inhibition efficiency. A suitable mechanism of corrosion inhibition has been proposed which is based on the results obtained from polarization study and uv‐visible absorption and reflectance spectra. 2‐Cl EPA‐Zn2+ system appears to function as a mixed inhibitor. The protective film consisted of Fe2+ ‐2‐Cl EPA complex, Zn(OH)2 and oxides of iron. The film was found to be semiconducting in nature.
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S. Rajendran, B.V. Apparao and N. Palaniswamy
2‐chloroethyl phosphonic acid (2‐Cl EPA) and Zn2+ show a synergistic effect in controlling corrosion of carbon steel in a neutral aqueous environment containing 60 ppm Cl‐. The…
Abstract
2‐chloroethyl phosphonic acid (2‐Cl EPA) and Zn2+ show a synergistic effect in controlling corrosion of carbon steel in a neutral aqueous environment containing 60 ppm Cl‐. The protective film consists of Fe2+–2–Cl EPA complex and Zn(OH)2; it is found to be uv‐luminescent.
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S. Rajendran, B.V. Apparao and N. Palaniswamy
The inhibition efficiencies of 2‐carboxyethyl phosphonic acid (2 CEPA) – Zn2+ system and ethyl phosphonic acid (EPA) – Zn2+ system in controlling corrosion of mild steel in a…
Abstract
The inhibition efficiencies of 2‐carboxyethyl phosphonic acid (2 CEPA) – Zn2+ system and ethyl phosphonic acid (EPA) – Zn2+ system in controlling corrosion of mild steel in a neutral aqueous environment containing 60ppm CI– have been compared. Polarization study reveals that both the systems function as mixed inhibitors. The inhibition efficiencies of these systems decrease with period of immersion due to the dissolution of the protective film as the period of immersion increases. The 2 CEPA – Zn2+ system has a better inhibition efficiency than the EPA–Zn2+ system. This is due to the fact that the amount of Fe2+– 2 CEPA complex present on the metal surface is higher than that of Fe2+– EPA complex, as revealed by fluorescence spectra. The molecular size of the iron phosphonate complex exercises a greater influence than the electronic (inductive) effect of the substituent in controlling corrosion of mild steel in chloride environment.
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Susai Rajendran, B.V. Apparao and N. Palaniswamy
The formulation consisting of 50ppm polyacrylamide (PAA), 300ppm phenyl phosphonic acid (PPA) and 50ppm Zn2+ has 95 per cent inhibition efficiency in controlling corrosion of mild…
Abstract
The formulation consisting of 50ppm polyacrylamide (PAA), 300ppm phenyl phosphonic acid (PPA) and 50ppm Zn2+ has 95 per cent inhibition efficiency in controlling corrosion of mild steel in a neutral aqueous environment, containing 60ppm Cl—, a situation commonly encountered in cooling water systems. A discussion of mechanistic aspects of corrosion inhibition is based on the results obtained from a potentiostatic polarization study, UV‐visible, FTIR and luminescence spectra. The protective film is found to be luminescent and to consist of Fe2+‐PAA complex, Fe2+‐PPA complex and Zn(OH)2.
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Susai Rajendran B. and N. Palaniswamy
The formulation consisting of 300ppm 1‐hydroxyethane‐1, 1‐diphosphonic acid (HEDP) and 50ppm Zn2+ offered 99 per cent inhibition to the corrosion of mild steel immersed in neutral…
Abstract
The formulation consisting of 300ppm 1‐hydroxyethane‐1, 1‐diphosphonic acid (HEDP) and 50ppm Zn2+ offered 99 per cent inhibition to the corrosion of mild steel immersed in neutral aqueous environment containing 60ppm chloride. This formulation functioned as a mixed inhibitor. The protective film was found to be luminescent and to consist of Fe2+‐HEDP complex and Zn(OH)2.
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S. Rajendran, B.V. Apparao and N. Palaniswamy
The inhibition efficiency of the HEDP‐Zn2+ system, in a wider concentration range of Zn2+ and HEDP (10, 50, 100, 150, 200 and 300ppm), in controlling corrosion of mild steel…
Abstract
The inhibition efficiency of the HEDP‐Zn2+ system, in a wider concentration range of Zn2+ and HEDP (10, 50, 100, 150, 200 and 300ppm), in controlling corrosion of mild steel immersed in low chloride medium (Cl‐ = 60ppm) has been evaluated by weight‐loss study. Synergism parameters have been calculated between HEDP and Zn2+. The plot of C/θ vs. C gives a straight line. The HEDP‐Zn2+ system functions as a mixed inhibitor. The protective film has been analysed by UV‐visible reflectance spectra and X‐ray diffraction.
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Meghana Kammeta and N.K. Palaniswamy
In everyday life, people generally wear two layers of clothes (a knitted vest and a knitted t-shirt) during the summer. It is essential to understand which types of innerwear and…
Abstract
Purpose
In everyday life, people generally wear two layers of clothes (a knitted vest and a knitted t-shirt) during the summer. It is essential to understand which types of innerwear and outerwear maximize comfort. The primary objective of this research is to investigate the influence of layering outerwear on innerwear, as well as the air gap between two layers, on thermal comfort properties.
Design/methodology/approach
In this study, a total of 12 combinations were created from four vest fabrics and three T-shirt fabrics. The thermal properties (thermal conductivity, thermal resistance, thermal absorptivity, thermal diffusion and peak heat flow) were evaluated for the individual inner and outer layers. Each inner layer was layered with an outer layer to observe the effect of layering on the thermal properties. An air gap of 2 mm was introduced between the inner and outer layers to study the effect of air gap on thermal properties.
Findings
Tencel fibre exhibits higher thermal conductivity and absorptivity than cotton and polyester. Upon layering an outer layer on an inner layer, the thermal conductivity and thermal absorptivity increase to a slight extent, thermal resistance and diffusion increase drastically and the peak heat flow reduces. With an air gap between the two layers, the thermal conductivity did not improve, the difference in thermal resistance among all the combinations reduced, the thermal absorptivity of the combination textiles was lower than that of the innerwear alone, the thermal diffusion increased and the peak heat flow diminished for all the combinations.
Practical implications
In practice, this comprehensive thermal comfort analysis provides specific combinations of inner and outer articles of clothing that are most appropriate for enhancing comfort during the summer season.
Originality/value
Though there are many studies on the effect of multilayer fabrics on thermal properties, no extensive research analyses the influence of innerwear and outerwear combinations on thermal comfort properties.