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Corrosion protection efficiency of any protective system depends not only on the nature and quality of the coating system used but also on the condition of the mrface on which it is to be applied. Various metal cleaning methods include (a) chemical cleaning — solvent degreasing, alkali cleaning and acid pickling (b) mechanical cleaning — shot blasting and (c) chemical conversion coatings — phosphating. Several of the recent advances in the field of prepaint treatment of steel have had as an objective the provision of an intrinsically fine, compact, well adhered zinc phosphate coating. Studies in this direction have been carried out in Central Building Research Institute, Roorkee and conditions for a suitable phosphating process have been optimised. Some work on the development of zinc rich paints based on both inorganic as well as organic binders have already been reported. The study has been extended by evaluating the performance of these zinc rich coatings on phosphated steel panels. In this report the performance of the above mentioned coatings when applied on the phosphated steel panels have been discussed. The studies reported include the preparation of the phosphated mild steel panels having three levels of coating wight ranging between 1.5–7.5 g/m2 (obtained by varying only the immersion time and keeping other parameters similar). A cost of zinc rich paint (75m?) based on either sodium silicate or chlorinated rubber binder was then applied on these panels along with the unphosphated ones. Comparison of the corrosion protection efficiency of the various systems thus obtained was carried out by using both laboratory and accelerated laboratory tests as well as by outdoor exposure studies. The performance of the coatings on phosphated panels has been remarkedly satisfactory as compared to the unphosphated panels. This is particularly so when the coating weight of the phosphate layer is between 4.5–7.5 g/m2; there is not any marked difference in the performance of paints applied on a phosphated layer with a coating weight of about 1.5 g/m2 as compared to the unphosphated panels.

The purpose of this paper is to synthesize a novel kind of crown‐type phosphate ionic liquids with better tribological properties for steel/Al system. The anions of crown‐type phosphate ionic liquids contain no F element, which are non‐corrosive to metal.

To improve the tribological properties of ionic liquid lubricants for the extremely difficult system of the steel‐against‐aluminum metal couple, novel crown‐type phosphate ionic liquids were prepared. The tribological properties of the crown‐type phosphate ionic liquids were evaluated at different loads and frequencies on an Optical SRV oscillating friction and wear tester. The morphology and chemical compounds of the wear scars were investigated by scanning electron microscope (SEM) and X‐ray photoelectron spectroscopy (XPS).

Compared with conventional ionic liquids, the novel crown‐type phosphate ionic liquids prepared in the present work exhibit a more excellent anti‐wear ability for steel/Al2024 contact at different loads and frequencies. By the morphological analysis with SEM, less debris was observed in the worn surface lubricated with crown‐type phosphate ionic liquids, though more debris was observed when lubricated with LB106 and LP106. By the XPS analysis, boundary lubrication film composed of aluminum (III) oxide, organometallic compounds, and silicon aluminum phosphate were found in the worn surface. Namely, the tribological behaviors of the crown‐type phosphate ionic liquids could be attributed to their stronger adsorption and tribochemical interactions with the Al alloys.

Because of the higher mean friction coefficients of crown‐type phosphate ionic liquids in the research, researchers are encouraged to modify their structure for better tribological properties.

The crown‐type phosphate ionic liquid exhibited better anti‐wear performance for steel/aluminum contact than the conventional ionic liquids containing F element. This will expand the application of high strength aluminum alloys.

The phosphate ionic liquid is a non‐corrosive liquid and would not cause metal corrosion. Also, the tribological properties of crown‐type phosphate ionic liquid with steel/aluminum contact are better than that of conventional ionic liquids. By the designing of molecular structure, new phosphate ionic liquids will exhibit excellent tribological properties: lower wear volume and lower friction coefficient.

This paper aims to report the influence of hexamethylenetetramine (HMTA) on phosphate coatings formed on AZ31 magnesium alloys.

These phosphate coatings were obtained by immersing magnesium alloys in phosphate baths with HMTA. The morphology and composition of the phosphate coatings were investigated via scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction.

The phosphate coatings were mainly composed of CaHPO₄·2H₂O. The HMTA concentration in the phosphate bath influenced the crystallization and corrosion resistance of the phosphate coating.

The polarization curve shows that the anti-corrosion qualities of the phosphate coating were optimal when the HMTA concentration was 1.0 g/L in the phosphate bath. Electrochemical impedance spectroscopy (EIS) shows that the electrochemical impedances increased gradually when the HMTA concentration varied from 1.0 to 3.0 g/L.

Historically, paints designed to protect steel and other metals have been formulated using anticorrosive chromate pigments, which are currently under environmental restrictions. During the investigation reported here, various phosphate compounds. The pigments prepared were characterised using a variety of chemical and spectrophotometric methods of analysis including emission atomic absorption, transmission electron microscope, X‐ray diffraction, in addition to thermal gravimetric analysis. The pigments were also evaluated according to relevant international standard testing methods. The phosphates prepared were incorporated into anticorrosive paint formulations, to replace the imported zinc phosphate pigment, containing medium oil alkyd resin, and melamine formaldehyde resin. Paint films obtained were tested in artificial seawater for 28 days for anticorrosion properties. The results indicated that the paint films had good anticorrosive protection properties that could be attributed to the pigments prepared and the resins used.

The phosphate treatment of metals has been in industrial use for over 50 years and is the most widely used method of treating light‐gauge steel as a preparation for painting; in addition, during the last 20 years, its use as an aid in the cold forming of steel in such operations as tube and wire drawing has been established. As a result of these trends, phosphating is now a very significant part of the whole metal finishing industry. This review includes advancements in operation, composition and use.

Aluminum phosphate is useful catalyst for many reactions. There are a lot of reports about catalytic activities of aluminum phosphate, however little reports about the relationship among the preparation, composition, catalytic activity of this phosphate. Phosphates transform to various other phosphates with hydrolysis and dehydration reactions by heating. In this work, some aluminum orthophosphates and condensed phosphates were prepared, and their compositions were estimated. Furthermore, specific surface area, acid strength, the amount of acidic sites, and the catalytic activities for the decomposition of trifluoromethane of these salts were investigated. Aluminum ortho‐ and polyphosphates were prepared in the systems of ortho‐ and poly‐phosphates. The catalytic activity for decomposition of CHF3 was related with a certain degree of specific surface area, acid strength, and the amount of acidic sites. Aluminum orthophosphate with a small amount of sodium cation had higher catalytic activity at lower temperature.

This study aims to investigate the influence of polyepoxysuccinic acid sodium (PESA), a green antiscalant, on the nucleation, crystallization and precipitation of magnesium phosphate.

The conductivity method was used to investigate the maximum relative supersaturation of magnesium phosphate across various PESA dosages. Subsequently, a magnesium phosphate scale was prepared using the static scale inhibition method (GB/T16632-1996) and then analyzed via scanning electron microscopy.

The findings showed that PESA extends the induction period of magnesium phosphate crystallization, reduces crystal growth rate and elevates the solution’s relative supersaturation. Notably, PESA exerts a low dosage effect on inhibition of the magnesium phosphate scale, with the optimal dosage identified at 10 mL. Scanning electron microscopy revealed that PESA dispenses a dispersing effect on the magnesium phosphate scale, generating numerous concave, convex and deeper pores on the scale particles’ surface, and thereby significantly enhancing the surface area, especially when using an antiscalant with variable dosages.

This study sheds new light on the impact of PESA, a green antiscalant, on the crystallization and precipitation of magnesium phosphate, thus paving the way for the development of enhanced and eco-friendly scale inhibition strategies in future applications.

This paper aims to achieve phosphating via optimal features of Mg metal as a suitable base coating, which is considered for other properties such as barrier properties against the passage of several factors.

In this research, in the phosphate bath, immersion time, temperature and the content of sodium nitrite as an accelerator were changed.

As a result, increasing the immersion time of AZ31 Mg alloy samples in the phosphating bath as well as increasing the ratio of sodium dodecyl sulfate (SDS) concentration to sodium nitrite concentration in the phosphating bath formulation increase the mass of phosphating formed per unit area of the Mg alloy. The results of the scanning electron microscope test showed phosphating is not completely formed in short immersion times, which is a thin and uneven layer.

Mg and its alloys are sensitive to galvanic corrosion, which would lead to generating several holes in the metal. As such, it causes a decrease in mechanical stability as well as an unfavorable appearance.

Mg is used in several industries such as automobile and computer parts, mobile phones, astronaut compounds, sports goods and home appliances.

Nevertheless, Mg has high chemical reactivity, so an oxide-hydroxide layer is formed on its surface, which has a harmful effect on the adhesion and uniformity of the coating applied on Mg.

By increasing the ratio of SDS concentration to sodium nitrite concentration in the phosphating bath, the corrosion resistance of the phosphating increases.

The purpose of this paper is to present a new trend of anticorrosive pigments based on bulk (core) of zinc oxide covered with a surface layer of phosphates.

A new batch of pigments based on core‐shell theory containing a core (bulk) of cheap oxides covered by a layer of phosphates were prepared. These new pigments combined the properties of both components besides being more economically feasible. Simple chemical techniques were used to prepare these pigments. Characterization of these pigments using X‐ray diffraction and scanning electron microscopy was carried out. Evaluation of these pigments using international standard testing methods was estimated. These pigments were incorporated in solvent‐based paint formulations based on medium oil alkyd resin. The physico‐mechanical properties of dry films and their corrosion properties using an accelerated laboratory test in 3.5 percent NaCl for 28 days were tested.

It was found that those pigments based essentially on zinc oxide covered with a surface layer of phosphates were easily prepared, are economically feasible and can successfully replace original phosphates with similar efficiency in their corrosion protection behaviour.

These pigments can be applied in other polymer composites, e.g. rubber and plastics, as a reinforcing agent.

The prepared pigments are environmentally friendly and can replace other hazardous pigments (e.g. chromates) with almost the same quality in their performance; also they can be used in industries other than paints, e.g. paper, rubber and plastics composites.

The purpose of the paper is to show the corrosion effect of benzotriazole in comparison with iron phosphate (PFe) coating as a sealer for the PFe layer in carbon steel paint pre-treatment and to show its ecological advantages as a more environment-friendly inhibiting compound than PFe.

Samples of carbon steel (SAE 1010) were phosphated in two baths, one containing iron PFe and PFe and BTAH (PFe + BTAH). Anodic potentiostatic polarization curves and electrochemical impedance spectroscopy were used to evaluate the corrosion resistance of phosphated carbon steel in 0.1 molL−1 H₂SO₄, 0.5 molL−1 NaCl and 0.1 molL−1 NaOH. The phosphate layers obtained were analyzed by infrared spectroscopy. Surface observation by scanning electron microscopy (SEM) showed that the PFe and PFe + BTAH layers are deposited as crystals with granular morphology. The electrochemical results showed that the PFe + BTAH coating was more effective in corrosion protection of the carbon steel.

This paper presents the application of benzotriazole as post-treatment of PFe-coated carbon steel. The results show that benzotriazole improves the phosphate layer properties. The SEM micrographs showed that the layer formed in PFe and PFe + BTAH baths consists of grain-like crystals, and infrared results revealed the BTAH presence in PFe phosphate. The corrosion resistance results showed higher efficiency associated to the PFe + BTAH phosphate layer relative to that of PFe. From the present study, results can be concluded that BTAH can be used as a post-treatment for PFe phosphate coating.

This paper deals with the corrosion resistance and surface carbon steel characterization of a new sealer for PFe coating, which has been prepared for this study and was never tested previously. These are candidate materials for substitution of chromium sealer. The BTAH sealer presents environmental and corrosion resistance advantages when compared with the post-treatment based on chrome. Although BTAH improves PFe layers’ properties, it is the worst phosphate coating. This manuscript has never been previously submitted and deals with original results.