Search results
1 – 10 of 990Amruta Joglekar-Athavale, Ganapati Shankarling, Satishchandra Dubey, Vinita Deshpande, Bikashkumar Jaiswal and Arun Nayak
The spectrally selective solar absorption paint is prepared from spinel-based mixed metal oxides with inorganic binder as a key component. Inorganic binder (furnace cement) is…
Abstract
Purpose
The spectrally selective solar absorption paint is prepared from spinel-based mixed metal oxides with inorganic binder as a key component. Inorganic binder (furnace cement) is blended with mixed metal oxide pigment during synthesis. High temperature stability upto 1,100ºC is achieved by the use of this modified coating system. The purpose of this paper is to work on solar selective coating synthesis, and application of a coating as a water-borne paint is the additive key feature that helps in reduction of solvent use.
Design/methodology/approach
The paint was formulated using water-based system, and the main component of colorant was made by mixed metal oxide–based spinel pigment and highly temperature stable inorganic binder.
Findings
The paint formed shows excellent absorptive power with low emittance even at high temperature. Optical and thermal properties were determined along with adhesion, abrasion and other properties. The solar absorptance for these samples were as = 0.93–0.95 with corresponding thermal emittance of eT = 0.096 (at room temperature) and 0.2–0.22 (at elevated temperature 100°C).
Originality/value
The paint formed shows excellent absorptive power with low emittance even at high temperature. The paint can be applied in solar absorptive tower system. The obtained results indicated excellent thermal stability of prepared paint coatings. As inorganic binder was used, the paint has reduction in solvent use, and being water as a base, it is environment friendly, easy to apply and durable at high temperatures, as the binder itself is stable up to 1,500ºC.
Details
Keywords
Osama A. G. Wahba, Ali M. Hassan, H. Abd El-wahab, A. Mohy-Eldin, A.M. Naser and Osama A. Fouad
The purpose of this paper is to investigate the synthesis of calcium-based group of mixed metal oxide (MMO) pigments. The evaluation of these pigments as heat and corrosion…
Abstract
Purpose
The purpose of this paper is to investigate the synthesis of calcium-based group of mixed metal oxide (MMO) pigments. The evaluation of these pigments as heat and corrosion resistant was also explored.
Design/methodology/approach
Two simple synthesis techniques, namely, co-precipitation and solid-state calcination method, were used to synthesise nanosized MMO pigments. And then the physico-chemical requirements according to standards for the synthesised pigments are investigated.
Findings
The prepared MMO pigments were mainly in the single phase double oxide forms. The prepared oxides exhibited good heat (up to 600°C) and corrosion resistance properties (in 5 per cent NaCl for 500 h).
Research limitations/implications
This paper investigates the physico-chemical properties of synthesised calcium-based group of MMO pigments. And then evaluate it as heat and corrosion resistant paints. The simple techniques used for synthesis of nanosized MMO pigments will significantly improve the research and development of pigments’ structure and performance.
Practical implications
Calcium-based MMO pigments can be used as heat and corrosion resistant pigments. The easy synthesis of the mixed oxide pigments will open the door for further vital special industrial uses and applications.
Originality/value
Low cost, simple techniques and using naturally abundant material can be used for mass production of some other low-cost nanosized materials.
Details
Keywords
H. Abd El-Wahab, A.M. Hassan, A.M. Naser, O.A. Fouad, A.M. El-Din and O.A.G. Wahba
The purpose of this paper was to prepare and evaluate a nanosized mixed calcium iron oxide as a high heat-resistant pigment. Heat-resistant pigments can be defined as chemical…
Abstract
Purpose
The purpose of this paper was to prepare and evaluate a nanosized mixed calcium iron oxide as a high heat-resistant pigment. Heat-resistant pigments can be defined as chemical substances that impart color to a substrate or binder and retain their color and finish at elevated temperatures. Mixed metal oxides have been widely used as pigments in coating formulations.
Design/methodology/approach
This work presents synthesis of nanosized calcium iron oxide as an inorganic pigment by using simple synthesis technique, namely, solid-state calcination method, to study its heat and corrosion resistance. The prepared pigment was characterized by using X-ray diffraction, infrared spectroscopy, scanning electron microscopy and inductive coupling plasma. It was incorporated into paint formulations, and the heat, corrosion and mechanical resistance of dry paint film was evaluated.
Findings
In this work, the prepared calcium iron oxide pigment showed excellent heat and corrosion resistance.
Research limitations/implications
Heat-resistant coatings are required for industrial applications, mainly for reactors, exhaust pipes, space craft, stacks and similar equipments that are permanently and occasionally exposed to elevated temperatures. It was previously quite difficult to formulate heat-resistant organic coatings because of binder deficiencies; new vehicles for such applications are now available. Thus, the development of silicon resins has markedly advanced the utility of heat-resistant paints. High-temperature pigments are inorganic chemical compounds that impart and retain their color and finish to a substrate or binder at elevated temperatures.
Practical implications
The nanosized mixed calcium iron oxide could be used as a pigment in paint formulations. It was found that it significantly enhances the heat, corrosion and mechanical resistance. It can also find numerous applications in other paint formulations for surface coating.
Originality/value
The paper shows how the pigment consisting nanosized mixed calcium iron oxide could be used in heat-resistant paint formulations for coating metal surfaces.
Details
Keywords
Petr Benda and Andréa Kalendová
The aim of the work is to develop an anticorrosion pigment based on an oxide mixture with lamellar particles. The pigments are prepared from lamellar zinc, zinc oxide and…
Abstract
Purpose
The aim of the work is to develop an anticorrosion pigment based on an oxide mixture with lamellar particles. The pigments are prepared from lamellar zinc, zinc oxide and magnetite by calcination. An alkaline earth carbonate is added when embedding a third cation in the lattice of the ferrite that forms the envelope of the lamellar zinc. The properties of the pigments are tested both in the powdered state and when embedded in an epoxy-ester system using different pigment volume concentrations (PVC).
Design/methodology/approach
The properties of paints containing synthesised oxide mixture-based pigments at various volume concentrations and with the Q factor – Q = PVC/CPVC = 0.65 – were examined (where CPVC is critical pigment volume concentration). A series of isometric ferrite pigments were also synthesised for a comparison. Paints of both types with PVC = 10, 15 and 20 per cent were formulated. Steel panels coated with the paints were subjected to corrosion and mechanical tests.
Findings
The oxide mixtures with lamellar particles were subjected to particle size analysis and found to make up a broad distribution curve. Electron microscopy photographs confirmed that the oxide mixture pigments contained lamellar particles with a surface layer. A high anticorrosion effect was achieved owing to the combination of different oxide types.
Research limitations/implications
The properties of the oxide mixtures with lamellar particles are described. Their particle distribution curves can be obtained by particle size analysis methods with a view to obtaining additional information on the status and properties of the pigment particles that may be useful in the development of better paints/coating materials.
Practical implications
Oxide mixtures with lamellar particles can be used in paints protecting construction steel.
Originality/value
The composition of the prepared oxide mixture-based pigments is novel. Each oxide acts by its own anticorrosion mechanism and the final beneficial effect is due to their concerted action.
Details
Keywords
Amruta Joglekar-Athavale and Ganapti S. Shankarling
A mixed metal oxide-based spinel ceramic pigment has been successfully synthesized incorporating inorganic, high-temperature stable furnace cement as an inbuilt binder. Step by…
Abstract
Purpose
A mixed metal oxide-based spinel ceramic pigment has been successfully synthesized incorporating inorganic, high-temperature stable furnace cement as an inbuilt binder. Step by step synthesis was done for the spinel and cement mix formulations.
Design/methodology/approach
The pigment mix was synthesized by a solid-solid method where the inorganic binder was incorporated in the mix. The results suggested that CoCuMn-based spinel ceramic pigment with cement mix could be obtained at an annealing temperature of 1,100ºC for 1 h and the size, morphology and crystallinity of spinel mix were greatly influenced by the calcination temperature.
Findings
The pigment mix synthesized was applied as a coating to different substrates such as aluminum, glass and Mild steel. The results revealed that spectral selectivity of TSSS paint coatings based on the CoMnCu spinel ceramic mix was much better than that of solvent-based coatings for high-temperature applications. The presence of cement as an inorganic binder makes the functioning and application of paint easy as it becomes that of a waterborne type.
Originality/value
Ease of application, stability at high temperatures, best absorptivity at the solar selective spectrum and excellent adhesion properties for the selected surface are the key features of the designed pigment system. The applied pigment mix was studied as a coating to get the results for solar selective system.
Details
Keywords
In this special feature details are given of those British paints which can be described as corrosion‐resistant primers, both one‐ and two‐pack. The materials are generally…
Abstract
In this special feature details are given of those British paints which can be described as corrosion‐resistant primers, both one‐ and two‐pack. The materials are generally classified according to the base or pigment which actively prevents corrosion—e.g. metallic zinc in zinc/epoxy formulations— or by the base which produces a barrier action against corrosion, e.g. bitumen in bituminous paints. Exceptions to this are the etching primers, which are separately classified. About 300 primers are described, the manufacturers' names and addresses being cross‐indexed and listed separately on page 48.
A. Kalendová, D. Veselý and P. Kalenda
The purpose of this paper is to synthesise X2TiO4 spinel‐type anticorrosion pigments and YTiO3, perovskite‐type anticorrosion pigments, where X = Zn, Mg, Ca, Sr; Y = Ca for metal…
Abstract
Purpose
The purpose of this paper is to synthesise X2TiO4 spinel‐type anticorrosion pigments and YTiO3, perovskite‐type anticorrosion pigments, where X = Zn, Mg, Ca, Sr; Y = Ca for metal protective paints.
Design/methodology/approach
Anticorrosion pigments were synthesised from oxides or carbonates at high temperature. The following pigments were synthesised: TiO2 · ZnO, 2TiO2 · ZnO, TiO2 · 2ZnO, TiO2 · MgO, TiO2 · CaO, TiO2 · ZnO · MgO, and TiO2 · ZnO · SrO. The pigments obtained were characterised by means of X‐ray diffraction analysis, measurement of particle sizes and scanning electron microscopy. The anticorrosion pigments synthesised were used to produce epoxy coatings with PVC = 10 per cent for each synthesised pigment. The coatings were tested for physical‐mechanical properties and in corrosion atmospheres. The corrosion test results were compared with those of alumino zinc phosphomolybdate.
Findings
A spinel or perovskite structure was found in the pigments synthesised. High anticorrosion efficiency was identified in all the synthesised pigments, the highest efficiency being demonstrated in the TiO2 · ZnO pigment of spinel structure and in the TiO2 · CaO pigment of perovskite structure.
Practical implications
The pigments synthesised can be conveniently used to protect metal bases from corrosion.
Originality/value
The use of pigments synthesised in anticorrosion coatings for metal protection presents a new approach. Its benefits are the use and the method of synthesising the anticorrosion pigments that do not contain heavy metals and that are acceptable for the environment.
Details
Keywords
Fawzia Fahim Abdel‐Mohsen and Hassan Salah Aly Emira
This work aimed to prepare black transition metal oxide pigments to be used as solar absorbers in the solar selective and other industrial paints.
Abstract
Purpose
This work aimed to prepare black transition metal oxide pigments to be used as solar absorbers in the solar selective and other industrial paints.
Design/methodology/approach
Mixed metal oxide CoCuMnOx spinel pigments were synthesised via the sol‐gel route. These oxides, namely (I‐Co0.50Cu0.25Mn0.25)Ox, (II‐Co0.25Cu0.50Mn0.25)Ox and (III‐Co0.25Cu0.25Mn0.50)Ox, were prepared with different molar ratios and annealed at 600, 800 and 900°C, respectively. The prepared oxides were characterised by infrared spectrometer (IS), differential scanning calorimetry analysis (DSC), X‐ray diffraction (XRD) and transmission electron microscope (TEM).
Findings
The prepared pigments have a spinel structure with the composition CoCuMnOx. All synthesised pigments consisted of nano particles ranged from 10 to 80 nm. The optical properties showed high absorption and moderately low reflectance in the solar wavelength range.
Research limitations/implications
The prepared samples, used in the present work, were synthesized from cobalt sulphate, copper chloride and manganese chloride. The salts were dispersed in polyacrylamide as a precursor.
Practical implications
The prepared samples were thermally stable and had good optical properties. They could be used as absorber materials in the painting of solar collectors.
Originality/value
These thermally stable mixed metal oxides could be used in the painting of solar collectors. The three mixed metal oxides could be used as absorber materials for heating solar collectors due to their high absorption and moderately low reflectance in the solar wavelength range.
Details
Keywords
N.M. Ahmed and M.M. Selim
Several solid solution combinations of aluminium oxide and iron oxide, for the preparation of a new pigment, were investigated to study the effect of aluminium oxide to iron oxide…
Abstract
Purpose
Several solid solution combinations of aluminium oxide and iron oxide, for the preparation of a new pigment, were investigated to study the effect of aluminium oxide to iron oxide ratio on various properties of the resulting pigments.
Design/methodology/approach
The conditions for the preparation of the pigments via solid solution interaction at 1,000°C had been estimated. Characterisation of three different combinations of aluminium oxide and iron oxide were carried out using spectroscopic methods of analysis via X‐ray diffraction (XRD), transmission and scanning electron microscopy (TEM and SEM). Also, evaluation of the pigments prepared, in terms of oil absorption, specific gravity, water‐soluble matter, and pH, using international standard testing methods was performed. The pigments prepared were incorporated in anticorrosive paint formulations based on medium oil alkyd resin as a binder. The physico‐mechanical properties of the relevant paint films were obtained, while their anticorrosive properties were assessed by tests in 3.5 per cent NaCl solution for 28 days.
Findings
The results showed that the anticorrosive protection properties of the pigment prepared were better than their aluminium and iron counterparts.
Research limitations/implications
The pigments prepared may be used in different applications other than paint formulations. As the concentration of iron oxide increases, the hardness and the anticorrosive protection performance of the paint film increase. As the concentration of aluminium increases, elasticity, impact resistance and ductility also increase. Application of different combinations of these pigments in paint films had been studied. However, investigation of the application of these pigments in other systems such as plastics could also be interesting.
Practical implications
The pigments prepared can be used as reinforcing filler in different rubber and plastic composites, beside its ferro‐magnetic properties. As the concentration of alumina increased, the reinforcing and magnetic effects decreased and vice versa.
Originality/value
Iron oxide is an abundant ore in several world countries; it is an inorganic, environmentally friendly material, which exhibits good Moh's hardness. Adding aluminium oxide which is a very light element having a unique flaky structure to iron oxide gave a new pigment that can be used not only in paint formulations, but also in rubber and plastic composites as reinforcing fillers.
Details
Keywords
It is well known that iron oxide, a pigment widely used in the paint industry, can not bring about chemical inhibition of the corrosion process. This pigment, however, belongs to…
Abstract
It is well known that iron oxide, a pigment widely used in the paint industry, can not bring about chemical inhibition of the corrosion process. This pigment, however, belongs to the semi‐conductor group and as such its structure is amenable to modification. The method essentially consists of mixing another oxide with iron oxide and subsequent calcination. The modified iron oxide was studied in four media viz., linseed oil, alkyd, chlorinated rubber and sodium silicate. The paints prepared in these media were evaluated by laboratory and natural weathering tests. The results have shown that the modified iron oxide pigment does bring about corrosion inhibition and that its performance is on a par with that of red lead in linseed oil and can be used with advantage. There is an overall saving in the cost of protection per unit area of iron and steel.