Zinc-rich Paints Research Articles

Friction Coefficient of Slip Critical Bolted Joints with Inorganic Zinc-Rich Paint Focusing on Contact Surface Pressure

Friction Coefficient of Slip Critical Bolted Joints with Inorganic Zinc-Rich Paint Focusing on Contact Surface Pressure

Electrolytic co-deposition of Zn-ZnO and Zn-ZnO-CaCO<sub>3</sub> composite substrates on low-carbon steel

Conventionally employed zinc-rich paints and coatings for marine corrosion protection of steel still comprise environmentally unfriendly compounds such as zinc phosphate. This paper is focused on developing eco-friendly zinc ternary composite coatings of Zn-ZnO-CaCO3 utilizing CaCO3 additives derived from tympanotonus fuscatus (periwinkle) shell and calcareous eggshell respectively on low-carbon steel using electrodeposition technique. This is aimed at improving not only the surface corrosion resistance of steel structures in marine environment but also the sustainability of raw materials and minimal environmental pollution. Corrosion studies of uncoated and coated steel samples in simulated marine environment were done using linear polarization technique. Results obtained suggested that CaCO3 (i.e., calcareous eggshell) additive in the composite coating significantly improved the corrosion performance of the substrate. Steel coated with calcareous eggshell additive displayed superior corrosion performance having highest polarization resistance, Rp (156090 Ω), lowest corrosion rate, CR (0.01 mm/year) and highest coating efficiency, Ceff (97%) as against those of uncoated, zinc oxide, and tympanotonus fuscatus shell additives after 30 minutes deposition time. Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS) results of selected developed coatings indicated presence of a homogeneous surface morphology and a significant amount of calcium in the calcareous eggshell coating.

Effect of Surface Coating Condition on High‐friction Organic Zinc‐rich Paints for HSFB Joints

AbstractWith the development of paints, high‐friction organic zinc‐rich paints with slip coefficients more than 0.45 have been advanced, making it possible to obtain more sophisticated and higher quality high strength bolted friction joints. Moreover, comparing to the inorganic zinc‐rich paints used at present, organic zinc‐rich paints are more appropriate for using in situ construction. However, since the application conditions of organic coatings have not been specified, it is recommended that a slip test should be carried out separately for each surface preparation to confirm the slip coefficient. In this study, slip tests were carried out on high strength bolted friction joint specimens to investigate the influence of high‐friction organic zinc rich paint film thickness and surface preparation on the slip coefficient. Furthermore, based on the experimental results, a surface preparation that can consistently produce a high slip coefficient is proposed.

Electrochemical Performance of Concrete Conductive Anode Paint Used as an Impressed Current Anode Material

The impressed current cathodic protection (ICCP) technique is a widely accepted technique to control corrosion of steel in reinforced concrete structures exposed to a high chloride environment. With the growing applicability of the technique, this research focused on developing a new anode material for the system. The author’s previous zinc-rich paint (ZRP) anode is further modified to improve its properties and its performance to be suitable for ICCP. The new concrete conductive anode paint (CAP) was evaluated for various concrete elements with varying steel: concrete ratios. Results showed that concrete CAP possesses excellent electrical conductivity as the anode for the ICCP system irrespective of specimen size. Compared with other available commercial anode paint materials and ZRP anode, concrete CAP is more promising as an ICCP anode material and satisfies the required polarization requirement. Polarization performance showed anode is capable to protect reinforced concrete structure with varied steel: concrete or steel: anode ratio. With an anode current density of 20 mA/m2, the service life was evaluated as 45 years.

Rapid and efficient extraction of Zn from wasted Zn-rich paint residue by indirect bioleaching and successive production of high-purity ZnCO3/ZnO by precipitation

Waste zinc-rich paint residue (WZPR) represents a typical hazardous waste containing both toxic organic substances and heavy metals. The extraction of Zn from WZPR by traditional direct bioleaching has been attracting attention owing to its eco-friendliness, energy conservation and low cost. However, a long bioleaching time and a low Zn release cast a shadow on the reputed bioleaching. To shorten the bioleaching time, the spent medium (SM) process was first used to free Zn from WZPR in this study. The results showed that the SM process had a much higher performance in Zn extraction. Zn removals of 100% and 44.2% (8.6 g/L and 15.2 g/L in the released concentration) were gained within 24 h under pulp densities of 2.0% and 8.0%, respectively, being over 1000 times of the release performance of Zn by previously reported direct bioleaching. On the one hand, the biogenic H+ in SM attacks ZnO to liberate Zn (Ⅱ) via quick acid dissolution. On the other hand, the biogenic Fe3+ not only highly oxidizes Zn0 in WZPR to generate and release Zn2+ but also intensely hydrolyzes to produce H+ to attack ZnO for further dissolution of Zn2+. Both biogenic H+ and Fe3+ contribute to over 90% of Zn extraction as the leading indirect bioleaching mechanism. Due to the high concentration of released Zn2+ and fewer impurity, the bioleachate was used to successfully produce high-purity ZnCO3/ZnO using a simple precipitation, thus achieving the high-value recycling of Zn in WZPR.

Characteristics of Corrosion Products of Friction-Type High-Strength Bolted Joints of Steel Bridge: A Case Study

The contact surface corrosion of friction high-strength bolt (FHSB) joints was analyzed to examine the characteristics of corrosion products and influence factors in steel bridges. Samples were selected from the Dongying Shengli Yellow River Bridge, which has been in service for 33 years. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were utilized to analyze the microscopic morphology and chemical composition of the corroded surface of the samples. The study identifies that construction quality issues accelerate corrosion of the contact surface and that the contact surface of the aluminum spraying layer transforms from rugged and dense to smooth and porous as corrosion increases. The findings also suggest that the friction coefficient of the FHSB connection node initially decreases and then increases as the corroded surface changes. Corrosion products contained S, Cl, Mn, Si, FeS, and their oxides, indicating that atmospheric, industrial, and Yellow River soil environments contribute to joint corrosion. The study proposes sandblasting and coating the corroded contact surface and deck steel plate with inorganic zinc-rich paint to prevent media penetration and delay substrate corrosion. Adopting ultra-high-performance concrete (UHPC) as the deck structure is also recommended to reduce top plate tensile stress, deck cracking, and media invasion. This study provides insights into the characteristics and mechanisms of FHSB joint corrosion to aid the maintenance, repair, and protection of steel bridges.

Effects of Surface Modification and Heat Treatment on the Storage and Application Properties of Waterborne Zinc-Based Paint

The high activity of metallic zinc particles with water, and consequently the short pot lift of a mixed waterborne organic zinc-rich paint, are the most well-known problem for their application. In this study, zinc powders were modified by silane-crosslinked potassium silicate and the paint’s pot life was prolonged. Electron microscopy analysis showed that the zinc spheres in the waterborne paint were encapsulated by the shell consisted of silane-crosslinked potassium silicate and resin. The modification allowed the paint stay fluid after storage for 36 h. Nevertheless, the thickened shell was found to deteriorate the cathodic protection provided by the zinc particles. As a repair strategy, the post-heat treatment performing on the coating could awaken the protective effect of zinc powders. The anti-corrosion performance of the repaired coatings was confirmed by electrochemical tests and salt spray tests.

Study on Modified Liquid Polysulfide Rubber Bimetallic Salt-Spray-Resistant Epoxy Coatings

In this study, liquid polysulfide rubber was modified by silane coupling agent. New kinds of anti-corrosion coatings with salt spray resistance and strong adhesion to the steel substrate were obtained using the modified liquid polysulfide rubber, bimetallic filler, carbon nanotubes, and epoxy resin. Infrared and nuclear magnetic resonance confirmed the preparation of new modified liquid polysulfide rubber through coupling reaction between the epoxy group of silane compound and the sulfide group of the liquid polysulfide rubber. A 1440 h neutral salt spray test showed the coating to be completely free of rust and blisters. The corrosion diffusion width of the scribed area was only 1.7 mm. In addition, in a 3.5% by weight NaCl solution, the coating shows no blistering and no corrosion phenomena compared with zinc-rich epoxy paints (the added zinc content was only 28.6%). These tests confirmed that the new coating had a dense microstructure, strong adhesion to the steel substrate, good corrosion resistance, and anti-blister performance. The performance indicates that the coatings have potential for use in the atmosphere and underwater, which provides a better choice for long-term protection of marine projects such as ships, wharves, offshore platforms, and wind power structures.

Slip resistance tests of friction-type high-strength bolted joints with one faying surface of etching-primered steel treated by power tools and the other painted by inorganic zinc-rich paint

Slip resistance tests of friction-type high-strength bolted joints with one faying surface of etching-primered steel treated by power tools and the other painted by inorganic zinc-rich paint

Corrosion Behavior of Carbon Steel Coated with a Zinc-Rich Paint Containing Aluminum Sulfate and Barium Oxide under Wet and Dry Cyclic Conditions

Corrosion Behavior of Carbon Steel Coated with a Zinc-Rich Paint Containing Aluminum Sulfate and Barium Oxide under Wet and Dry Cyclic Conditions

Zn bio extraction from a zinc rich paint sludge by indigenous Pseudomonas aeruginosa

Paint sludge is considered hazardous waste due to its heavy metals and high organic compounds. Incineration and landfilling are the methods of disposing of sludge collected from the paint spray of an automotive factory in Iran. Pseudomonas aeruginosa was isolated from water-based paint sludge using Bushnell-Haas medium and identified by chemical and molecular methods. A two-step bioleaching experiment using the Response surface methodology was used to investigated P. aeruginosa to mobilize the contaminant zinc metal from the paint sludge. Variables included temperatures from 32 to 37 °C, the rotation speed of shaker from 120 to 180 rpm, particle sizes from 1 to 3 mm, and bacteria were adapted to a pulp density of 7 g/L. When the bioleaching process was optimized at pH 7, temperature 32 °C, particle size 3 mm, and 180 rpm, the concentration of zinc decreased to 28.71%. A decrease in zinc of 27% was confirmed by repeating the experiment three times. The ANOVA test confirmed the most effective parameters were temperature and particle size. The most efficient process to remove zinc was achieved as a result of the effect between temperature and pH.

Paint Blistering Mechanism of Steel Painted with Paint System Containing Inorganic Zinc Rich Paint

Paint Blistering Mechanism of Steel Painted with Paint System Containing Inorganic Zinc Rich Paint

Effects of biochar nanoparticles on anticorrosive performance of zinc-rich epoxy coatings

Biochar nanoparticles (BCN) derived from spruce wood and wheat straw were prepared, characterized and incorporated into zinc-rich epoxy coatings, with the aim of improving the zinc powder utilization and the anticorrosion performance. Formulations with different BCN and commercial carbon black dosages (0.4 wt%, 0.8 wt% and 1.6 wt%) were compared to a zinc-rich epoxy paint (ZRP) without carbon addition. After immersion and salt spray exposure, coated steel panels were characterized with optical, electrochemical and spectroscopy techniques to evaluate the anticorrosive performance. BCN and carbon black addition enhanced the local electrochemical reactions and the barrier effects were promoted by an increased amount of zinc corrosion products (Zn5(OH)8Cl2 and ZnCO3). The formulation with 0.8 wt% of spruce wood BCN performed equivalently well compared to the ones with carbon black. The degraded area and rust accumulation around the artificial scribe for the formulation with 0.8 wt% of spruce wood BCN were 29.8% and 27.8% less than ZRP, respectively, which is attributed to the good electrical conductivity and high specific surface area of spruce wood char. These results suggest a promising and sustainable option for improving the anticorrosive performance of zinc-rich epoxy coatings by the incorporation of BCN.

Electrochemical Evaluation of Three Zinc-Rich Paints on Carbon Steel Substrates Exposed to 3.5% NaCl

Coatings are the most common method of corrosion control based on isolating a metal from the aggressive environment. They also represent one of the most effective tools to combat the degradation of metallic materials. This research work evaluates using electrochemical techniques, three paint systems rich in zinc: Zerovoc (Z1), ZRC Galvilite (Z2), and Zinga (Z3), on carbon steel substrates. As a first step, the different coatings were applied. Subsequently, the characterization was carried out using direct current (DC) and alternating current (AC) electrochemical techniques; Linear Polarization Resistance (LPR) and Electrochemical Impedance Spectroscopy (EIS). The systems were evaluated in a period of 30 days of immersion in 3.5% NaCl obtaining as a result a degradation mechanism and the corrosion rate for each paint. Based on the results, it was determined that the ZRC Galvilite (Z2) system represented the best protection performance.

Slip Resistance Tests of Friction-Type High-Strength Bolted Joints with One Faying Surface Roughened by Various Power Tools and the Other Painted by Inorganic Zinc-Rich Paint

Slip Resistance Tests of Friction-Type High-Strength Bolted Joints with One Faying Surface Roughened by Various Power Tools and the Other Painted by Inorganic Zinc-Rich Paint

VERIFICATION OF REPAIR PAINTING EFFECT OF CORRODED WEATHERING STEEL BY EXPOSURE TEST

Weathering steel generates dense protective rust on the steel surface. Since this protective rust would reduce corrosion speed, weathering steel can be used without any painting. Furthermore, the Life Cycle Cost of unpainted steel bridges would be lower than ordinary painted steel bridges. Due to these advantages, many weathering steel bridges have been constructed in recent years. Unfortunately, the generation of anomalous rust has been reported in some bridges, cause of water leakage or deicer. It is necessary to repair these bridges, but the repair technique for corroded weathering steel has never been established yet. This study aims to clarify the effect of various repair painting for corroded weathering steel by performing an exposure test. The exposure test has been carried out from September 2015 to Okinawa and Yamaguchi. Test in Okinawa is supplied airborne salt, and the test in Yamaguchi is not supplied airborne salt. Specimens, which produced anomalous rust, were repaired by 19 methods and exposed. As a result, it is effective to repair by organic zinc-rich paint in the area with airborne salt. On the other hand, it is appropriate to remove rust and salt on the steel surface by blasting in the area which is not supplied airborne salt.

Assessment of the possibility to use the of hot dip galvanizing waste-zinc dust for zinc-rich paints

The chemical and grain-size analysis of zinc dust – waste of hot – dip zinc plating were made. The research results showed that zinc dust is a dispersed waste with particles of mainly circular shape and sizes from 3 to 200 microns, and in chemical composition it mainly meets the requirements of ISO 3549. The presence of lead in the zinc dust composition, which is slightly higher than the acceptable level will be taken into account in the development of zinc-rich paints compositions. Analysis of the results of sieving of zinc dust showed that it contains particles of size £15 µm, which is about 27% of its fractional composition and which can be recommended for the manufacture of zinc-rich paints.

Long-term corrosion resistance of zinc-rich paint using functionalised multi-layer graphene-tripolyphosphate: in situ creation of zinc phosphate as corrosion inhibitor

ABSTRACTThis study investigates the effect of hybrid multilayer graphene-tripolyphosphate on long-term corrosion protection efficiency of zinc-rich paint. The hybrid nanomaterial as a corrosion resistance modifier was prepared trough a simple method by the addition of sodium tripolyphosphate aqueous solution to a dispersed multi-layer graphene in water/ethanol during stirring. The performance of the hybrid nanomaterial was studied by salt spray, electrochemical impedance spectroscopy, scanning electron microscopy, X-ray diffraction, cathodic delamination and pull-off adhesion test. The experimental results showed that in the presence of 1 wt-% of the hybrid nanomaterial, cathodic protection duration increased from 28 days to more than 50 days. The improvement in the barrier property and the cathodic delamination resistance was significant in the presence of the nanomaterial after two years long-term study. X-ray diffraction analysis showed that the formation of zinc phosphate was responsible for the higher corrosion protection efficiency.

Further Developments of a Modular One-Dimensional Analytical Galvanic Corrosion Model

Galvanic corrosion is an important topic in corrosion research and modelling can help us better understand this phenomena, especially at the joint interface between dissimilar metals. The objective of this work is to provide a simple to use and easily accessible one-dimensional analytical modelling tool that can be implemented within a spreadsheet program. This work is a further development of the modular analytical modelling approach introduced by G.L. Song in 2010.1 Three new types of building blocks (an “inert” block, a “linear transition” building block and a “sigmoid transition” building block) are introduced to the original set of three types of building blocks (a “left” building block, a “bridge” building block and a “right” building block) for this analytical modelling approach. This enhanced model also takes into account electrical resistivity of the electronic current path through the substrate material, which is important for materials that can have significant electrical resistivity, such as carbon composite materials and zinc-rich paints. With these new developments, this one-dimensional analytical modelling approach is now able to model a greater range of corrosion phenomena than previously possible, as the restrictions of having a constant solution resistivity and zero substrate electrical resistivity across all building blocks are removed. Case studies published in the corrosion literature are analyzed with this model to examine its validity and accuracy. An experimental system of zinc-rich paint on carbon steel was also investigated and analyzed with this model. The benefits and limitations of this approach will be discussed and possible techniques to improve the analytical model accuracy by judicious selection of input values and generation of “performance envelopes” shared. Reference: G. L. Song, Corros. Sci., 52, 455–480 (2010).

Performance assessment of specialist conductive paint for cathodic protection of steel in reinforced concrete structures

ICCP system provides effective corrosion protection in a chloride environment. This research evaluates the feasibility of zinc rich paints (ZRP) as ICCP anode for RC structures. The preliminary investigation showed the application of three layers of ZRP with medium concrete surface roughness and use of Cu/Nb/Pt wire as primary anode gives maximum bond strength and uniform current distribution across the ZRP coating. Moreover, polarization results showed satisfactory performance of the ZRP anode coating subjected to a current density of 12.5 mA/m2. The anode was found to be vapour permeable and effectively provide protection with a service life of up to 15 years.