Inhibitive action of tara tannin in rust converter formulation

2017 ◽  
Vol 64 (2) ◽  
pp. 136-147 ◽  
Author(s):  
Santiago Flores Merino ◽  
Juan José Caprari ◽  
Luis Vasquez Torres ◽  
Luis Figueroa Ramos ◽  
Antonella Hadzich Girola

Purpose The purpose of this paper is to study the ability of commercial tara powder to convert rust into iron tannate and evaluate their use as raw material for the formulation of water based rust converter. Design/methodology/approach Water-borne acrylic primers were formulated with tara powder and aqueous tara extract and applied on steel rusted by three different methods. The conversion of rusted steel by tara tannins was studied by X-ray diffraction spectroscopy, infrared spectroscopy and scanning electron microscopy. The acrylic primers, containing hydrolysable tannins, were coated with alkyd finish and were evaluated in comparison to commercial systems in accelerated corrosion tests. The corrosion inhibition effects of tara powder on mild steel in 0.1M NaCl were studied by DC electrochemical techniques. Findings Tara tannin converts rust to ferric tannate and increases the magnetite content of rusted steel. The water-based acrylic primer formulated with aqueous extract of tara, alkyd-coated finish, showed performance equivalent to pure alkyd system. Research limitations/implications The chlorides content in the commercial tara powder can be screened the beneficial effect of hydrolysable tannins to convert rust. Furthermore, the water-based rust converter formulated with acrylic resin may be sensitive to salt contamination of rust. Originality/value Hydrolysable tannins from commercial tara powder have not been studied yet in its application to the development of rust converters. A water-based primer formulated with commercial tara powder developed for the effective treatment of rusted surfaces can be of interest as an environmentally friendly to current commercial approaches.

2016 ◽  
Vol 45 (1) ◽  
pp. 24-29 ◽  
Author(s):  
Alireza Khataee ◽  
Leila Moradkhannejhad ◽  
Vahid Heydari ◽  
Behrouz Vahid ◽  
Sang Woo Joo

Purpose – This paper aims to study the Improvements in self-cleaning property of the white acrylic water-based paint by addition of different percentages of three commercially available titanium dioxide (TiO2) nanoparticles as additives. Then, due to the risk of destruction of polymeric materials in the presence of nanoparticles, degradation of dry paint film samples was investigated for 15 days using two important chalking and yellowing factors. Finally, the TiO2-modified paint sample with the best performance and optimum percentage of TiO2 nanoparticles that produced desired self-cleaning and dry film properties was introduced. Design/methodology/approach – Self-cleaning and dry film properties of white acrylic water-based paint were investigated by addition of three various types of commercial available TiO2 nanoparticles (SSP-25, STA-100 and KA-100). X-ray diffraction, transmission electron microscopy and Brunauer–Emmett–Teller were used for characterization of TiO2 samples. Colorimetric tests in decolourization of C.I. Basic Red 46 (BR46) were used for determination of self-cleaning properties of TiO2-modified paints in comparison with unmodified paint sample. Also, paints defects such as chalking and yellowing were tested along two weeks. Findings – The results indicated that, in all types of TiO2 nanoparticles, by increasing the amount of TiO2 in modified paint, self-cleaning property of the samples was enhanced. The paint containing SSP-25 indicated better self-cleaning properties than others due to its larger surface area. However, its usage above 3.5 weight per cent caused yellowing and chalking defects in dried paint film. Practical implications – In this research, TiO2-modified paint sample with the best performance in both self-cleaning and mechanical properties was selected among the nine sets of prepared paint samples. All the materials used in this research such as acrylic resin and three types of TiO2 nanoparticles are of industrial grade. Therefore, the introduced TiO2-modified paint sample has the potential for the commercial production as a building exterior paint. Originality/value – In the present study, an attempt at introducing a self-cleaning paint sample with acceptable mechanical properties using three types of commercially available TiO2 nanoparticles as additives and industrial grade of acrylic resin which is the most commonly used water-based resin in building paints, as binder. As far as it was searched in the literatures, the parallel study of the self-cleaning and mechanical properties of paints has not been reported as noteworthy. Self-cleaning property of the acrylic water-based paint samples was investigated by adding three types of the commercially available TiO2 nanoparticles. Also considering the possible detrimental effects of TiO2 nanoparticles on polymeric materials and consequently on physical properties of the paint, chalking and yellowing factors in dried paint samples were evaluated.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Renato Altobelli Antunes ◽  
Rodrigo Uchida Ichikawa ◽  
Luis Gallego Martinez ◽  
Isolda Costa

The aim of this work was to compare the corrosion products formed on carbon steel plates submitted to atmospheric corrosion in urban and industrial atmospheres with those formed after accelerated corrosion tests. The corrosion products were characterized by X-ray diffraction, Mössbauer spectroscopy, and Raman spectroscopy. The specimens were exposed to natural weathering in both atmospheres for nine months. The morphologies of the corrosion products were evaluated using scanning electron microscopy. The main product found was lepidocrocite. Goethite and magnetite were also found on the corroded specimens but in lower concentrations. The results showed that the accelerated test based on the ASTM B117 procedure presented poor correlation with the atmospheric corrosion tests whereas an alternated fog/dry cycle combined with UV radiation exposure provided better correlation.


2016 ◽  
Vol 63 (2) ◽  
pp. 89-96 ◽  
Author(s):  
Patrícia Alves Saliba ◽  
Milene Adriane Luciano ◽  
Maria das Mercês Reis Castro ◽  
Vanessa Freitas Cunha Lins

Purpose – The purpose of this study is to evaluate the quality of organometallic coatings of automotive fuel tanks. Galvannealed steels and galvannealed steels coated with organometallic layers were analyzed using accelerated corrosion tests. Design/methodology/approach – The characterization of galvannealed and organometallic coatings was done by mass (layer removal and weighing) and layer thickness (glow discharge optical emission spectroscopy and scanning electron microscopy), chemical composition (energy dispersive spectroscopy) and surface morphology (scanning electron microscopy). The accelerated corrosion tests were performed in accordance with SAE J2334 and GMW 14872 standards. Findings – The samples tested using the GMW 14872 standard were more deteriorated as compared to the samples submitted to the SAE J2334 test because of the higher degree of aggressiveness of the GMW 14872 test. Despite the presence of white rust, the corrosion resistance of organometallic-coated steel samples was higher as compared to the resistance of galvannealed steel samples. Research limitations/implications – The organometallic coating is a commercial product, whose chemical composition is confidential. Practical implications – This study reinforces the quality of automotive tanks with organometallic coating and helps to increase their competitiveness in the market tanks as compared to polymeric tanks. Social implications – The study contributes to increase the competitiveness of steel tanks against polymeric tanks that meet the technical requirements but are not environmentally friendly because they are multi-layered and cannot be recycled. Originality/value – The novelty of this study is the comparison of the corrosion resistance of galvannealed steel tanks and galvannealed steel tanks with organometallic coatings. This corrosion evaluation joined with the physical and chemical characterization was not found in literature and is relevant to the materials selection of the automotive industry.


2019 ◽  
Author(s):  
Chem Int

The anti-corrosive properties of sulphadoxine + pyrimethamine (S+P) on the corrosion of pipeline steel in acidic environment were investigated using electrochemical techniques. The results obtained showed an excellent inhibition efficiency which increased with increase in inhibitor concentration. The corrosion inhibition efficiency increased up to 99.04 % at 0.01M S+P and decreased with rise in temperature down to 85.93 % at 333 K and 0.01 M S+P, suggesting a physiosorptive mechanism of adsorption. Also the adsorption data was fitted into Langmuir and Temkin adsorption isotherms, while the inhibitive action was shown to proceed by mixed inhibition mode.


1998 ◽  
Vol 25 (1) ◽  
pp. 81-86 ◽  
Author(s):  
N Hearn ◽  
J Aiello

Experimental work on prismatic concrete specimens was conducted to determine the relationship between mechanical restraint and the rate of corrosion. The current together with the changes in strain of the confining frame were monitored during the accelerated corrosion tests. The effect of mix design and cracking on the corrosion rates was also investigated. The results show that one-dimensional mechanical restraint retards the corrosion process, as indicated by the reduction in the steel loss. Improved quality of the matrix, with and without cracking, reduces the rate of steel loss. In the inferior quality concrete, the effect of cracking on the corrosion rate is minimal.Key words: corrosion, concrete, repair.


2018 ◽  
Vol 47 (4) ◽  
pp. 350-359 ◽  
Author(s):  
Nivin M. Ahmed ◽  
Mostafa G. Mohamed ◽  
Reham H. Tammam ◽  
Mohamed R. Mabrouk

Purpose This study aims to apply novel anticorrosive pigments containing silica fume-phosphates (Si-Ph), which were prepared using core-shell technique by covering 80-90 per cent silica fume (core) with 10-20 per cent phosphates (shell) previously, to play dual functions simultaneously as anticorrosive pigments in coating formulations and as an anticorrosive admixture in concrete even if it is not present in the concrete itself. Two comparisons were held out to show the results of coatings on rebars containing core-shell pigments in concrete, and concrete admixtured with silica fume can perform a dual function as anticorrosive pigment and concrete admixture. The evaluation of corrosion protection efficiency of coatings containing core-shell pigments and those containing phosphates was performed. Design/methodology/approach Simple chemical techniques were used to prepare core-shell pigments, and their characterization was carried out in a previous work. These pigments were incorporated in solvent-based paint formulations based on epoxy resin. Different electrochemical techniques such as open-circuit potential and electrochemical impedance spectroscopy were used to evaluate the anticorrosive efficiency of the new pigments. Findings The electrochemical measurements showed that concrete containing coated rebars with core-shell pigments exhibited almost similar results to that of concrete admixtured with silica fume. Also, the anticorrosive performance of coatings containing Si-Ph pigments offered protection efficiency almost similar to that of phosphates, proving that these new pigments can perform both roles as anticorrosive pigment and concrete admixture. Originality/value Although the new Si-Ph pigments contain more than 80 per cent waste material, its performance can be compared to original phosphate pigments in the reinforced concrete.


2020 ◽  
Vol 849 ◽  
pp. 113-118
Author(s):  
Yayat Iman Supriyatna ◽  
Slamet Sumardi ◽  
Widi Astuti ◽  
Athessia N. Nainggolan ◽  
Ajeng W. Ismail ◽  
...  

The purpose of this study is to characterize Lampung iron sand and to conduct preliminary experiments on the TiO2 synthesis which can be used for the manufacturing of functional food packaging. The iron sand from South Lampung Regency, Lampung Province that will be utilized as raw material. The experiment was initiated by sieving the iron sand on 80, 100, 150, 200 and 325 mesh sieves. Analysis using X-Ray Fluorescence (XRF) to determine the element content and X-Ray Diffraction (XRD) to observe the mineralization of the iron sand was conducted. The experiment was carried out through the stages of leaching, precipitation, and calcination. Roasting was applied firstly by putting the iron sand into the muffle furnace for 5 hours at a temperature of 700°C. Followed by leaching using HCl for 48 hours and heated at 105°C with a stirring speed of 300 rpm. The leaching solution was filtered with filtrate and solid residue as products. The solid residue was then leached using 10% H2O2 solution. The leached filtrate was heated at 105°C for 40 minutes resulting TiO2 precipitates (powder). Further, the powder was calcined and characterized. Characterization of raw material using XRF shows the major elements of Fe, Ti, Mg, Si, Al and Ca. The highest Ti content is found in mesh 200 with 9.6%, while iron content is about 80.7%. While from the XRD analysis, it shows five mineral types namely magnetite (Fe3O4), Rhodonite (Mn, Fe, Mg, Ca) SiO3, Quart (SiO2), Ilmenite (FeOTiO2) and Rutile (TiO2). The preliminary experiment showed that the Ti content in the synthesized TiO2 powder is 21.2%. The purity of TiO2 is low due to the presence of Fe metal which is dissolved during leaching, so that prior to precipitation purification is needed to remove impurities such as iron and other metals.


Author(s):  
F. Mostefa ◽  
Nasr Eddine Bouhamou ◽  
H.A. Mesbah ◽  
Salima Aggoun ◽  
D. Mekhatria

This work aims to study the feasibility of making a geopolymer cement based on dredged sediments, from the Fergoug dam (Algeria) and to evaluate their construction potential particularly interesting in the field of special cementitious materials. These sediments due to their mineralogical composition as aluminosilicates; are materials that can be used after heat treatment. Sedimentary clays were characterized before and after calcination by X-ray diffraction, ATG / ATD, spectroscopy (FTIR) and XRF analysis. The calcination was carried out on the raw material sieved at 80 μm for a temperature of 750 ° C, for 3.4 and 5 hours. The reactivity of the calcined products was measured using isothermal calorimetric analysis (DSC) on pastes prepared by mixing an alkaline solution of sodium hydroxide (NaOH) 8 M in an amount allowing to have a Na / Al ratio close to 1 (1: 1). Also, cubic mortar samples were prepared with a ratio L / S: 0.8, sealed and cured for 24 hours at 60 ° C and then at room temperature until the day they were submited to mechanical testing. to check the extent of geopolymerization. The results obtained allowed to optimize the calcination time of 5 hours for a better reactivity of these sediments, and a concentration of 8M of sodium hydroxide and more suitable to have the best mechanical performances.


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