Montmorillonite as corrosion protective pigment (original) (raw)
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The Corrosion Inhibition of Montmorillonite Nanoclay for Steel in Acidic Solution
Materials
The aim of this research is to study the anticorrosive behavior of a coating consisting of modified montmorillonite nanoclay as an inorganic green inhibitor. The anticorrosion protection for mild steel in 1.0 M HCl solution is studied via weight loss, electrochemical methods, SEM, and XRD. The results proved that montmorillonite nanoclay acts as a good inhibitor with a mixed-type character for steel in an acidic solution. Both anodic and cathodic processes on the metal surface are slowed down. There is a clear direct correlation between the added amount of montmorillonite nanoclay and the inhibition efficiency, reaching a value of 75%. The inhibition mechanism involves the adsorption of the montmorillonite nanoclay onto the metal surface. Weight loss experiments are carried out with steel samples in 1.0 M HCl solution at room temperature, and the same trend of inhibition is produced. SEM was used to image the surface at the different stages of the corrosion inhibition process, and a...
Clay Minerals, 2018
ABSTRACTIranian montmorillonite (MMT) was modified with hexadecyltrimethylammonium bromide (HDTB) and used as a nano-additive for the enhancement of the mechanical and anticorrosion properties of an epoxy coating. Infrared (IR) spectroscopy, thermo-gravimetric analysis (TGA), transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis indicated that HDTB reacted with MMT (with 97% yield) and increased the d001 spacing of MMT from 1.27 to 3.92 nm. Some 1, 3 and 5 wt.% of organically modified montmorillonite (OMMT) were added to the epoxy coating formulation. XRD and TEM/image processing analysis showed that the extent of intercalation/exfoliation of OMMT was substantially greater than that of MMT. Dynamic mechanical analysis showed that the glass transition temperature and storage modulus increased significantly with the addition of OMMT. Electrochemical impedance spectroscopy (EIS) and salt spray/image processing results revealed that addition of OMMT to the epoxy co...
Effect of montmorillonite on properties of nanocomposite coatings
Surface Engineering, 2008
Unmodified or chemically modified montmorillonite (MMT) dispersed in water was added into the reaction mixture forming hybrid organic-inorganic (O-I) nanocomposite coating. Two basic systems made from functionalised trialkoxysilane and oligomeric diamine v. functionalised dialkoxysilane and triamine were prepared and compared. End properties depend not only on the concentration and kind of MMT used but also on the inner constitution of the O-I matrix. Already 1 wt-% of unmodified MMT influences considerably surface and mechanical properties, but the effect of chemically modified MMT is not so pronounced. This can be due to worse dispersion (scattering) of chemically modified MMT within the O-I matrix compared with unmodified one: while unmodified MMT is partially intercalated, partially exfoliated in the product, substantial amount of original, unaffected MMT clusters was found there. Solid state nuclear magnetic resonance spectroscopy confirmed the interaction of MMT platelets with the O-I matrix.
New fluorinated montmorillonites for the preparation of UV-cured coatings
Journal of Colloid and Interface Science, 2009
Montmorillonite was modified by means of a cation exchange reaction with two fluorinated ammonium salts, containing either a fluoroalkylic or a perfluoropolyether chain. The introduction of the fluorinated ammonium salts into the clay mineral galleries led in both cases to an increase of the interlayer distance, as revealed from the XRD spectra. However, the surfactant conformation achieved was different: a double layer structure was formed by the fluoroalkylic modifier, a paraffinic structure was present when the perfluoropolyether surfactant was used. This led to different results when the organoclays were dispersed into a typical UV curable dimethacrylate: a good degree of intercalation was achieved only with the clay modified by the fluoroalkylic surfactant.
Corrosion inhibition of galvanized steel with inorganic pigments
Materials Science
Lacquer coatings on a metal are, as a rule, multiple and consist of a base coating, several layers of the basic coating, and a decorative layer [1]. The base coating is a promoter of adhesion for such coatings and contains mainly inorganic inhibiting pigments which electrochemically protect the metal base after the formation of through defects in the coating and penetration of the corrosion medium into the metal. Chromate pigments are widespread anticorrosive modifiers for lacquer base coatings [ 1]. They efficiently protect steels against corrosion in neutral and weakly acid media. However, their application is limited by ecological requirements. At the same time, one intensively searches for substitutes of less harmful pigments for chromates. Before proceeding to the investigation of polymeric coatings containing anticorrosive pigments (possible substitutes for strontium chromate), it is necessary to estimate the protective function of extracts of these pigments without polymeric binder. Having analyzed the information on pigments produced by industry, we took strontium chromate, zinc phosphate modified with zinc molybdate, and aluminum triphosphate.
Montmorillonite: An Introduction to Properties and Utilization
Current Topics in the Utilization of Clay in Industrial and Medical Applications
Clay mineral is an important material available in nature. With an increasing understanding of clay structure, montmorillonite is realized viable for an enhanced performance in a variety of materials and products in the areas of catalysis, food additive, antibacterial function, polymer, sorbent, etc. Significant development in the use and application of montmorillonite is seen in recent time. This chapter provides an overview of montmorillonite, structure, and properties and particularly discusses its recent utilization in important materials. Montmorillonite is introduced in terms of its natural sources, chemical structure, physical and chemical properties, and functional utilization. The important physical and chemical properties are summarized as particle and layered structure, molecular structure and cation exchange effect, barrier property, and water sorption. This is followed by the important functional utilizations of montmorillonite based on the effects of its chemical structure. The important functional utilization of montmorillonite includes food additive for health and stamina, for antibacterial activity against tooth and gum decay, as sorbent for nonionic, anionic, and cationic dyes, and the use as catalyst in organic synthesis. The environment concerns, to date, do not indicate the adversity for particles used as additive. Studies will be useful which are clearly based on any montmorillonite structure to describe environmental effects.
Inhibition of corrosion by a mixture of nonchromate pigments in organic coatings on galvanized steel
Materials Science, 2004
We consider several possible substitutes for toxic chromate pigments. Among the most promising compositions for the corrosion inhibition of galvanized steel with a protective organic coating, we should mention a mixture of phosphate-and calcium-containing pigments. As was shown earlier, such a mixture possesses a high efficiency under conditions of the corrosion of zinc and galvanized steel sheet; however, it is less efficient for the protection of carbon steels. This pigment mixture forms an adsorbed phosphate film on the metal and hinders the course of anodic and cathodic reactions. Zinc ions play an important role for obtaining a synergistic protective effect, increasing the coherence and decreasing the porosity of the deposited film. Traditional and local electrochemical methods (EIS and SVE) were used for studying the corrosion of galvanized steel with coatings in acid rain solution. The data obtained corroborated the high anticorrosive efficiency of a pigment mixture in an organic coating on galvanized steel. In addition, we established some specific features of its inhibiting action near defects in the coating.
A multipurpose compound for protective coatings
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2008
International regulations concerning the protection of both the environment and industrial workers have prompted paint manufacturers and end users to look for suitable replacements for traditional pigments.