Chemical Immersion Research Articles

Methods to evaluate resistance of cement-based materials against microbially induced corrosion: A state-of-the-art review

Microbially induced corrosion (MIC) is a serious issue for sewer structures worldwide. Many studies have been carried out to develop more durable cement-based materials under the MIC attack. Due to a lack of a standard, various methods have been tried in the evaluation of resistance of different cement-based materials against MIC. A review of existing evaluation methods is needed to summarize these methods and their pros and cons. Therefore, this paper aims to conduct a state-of-the-art review of the existing evaluation methods of resistance against MIC. First, a review was focused on experimental evaluation methods, including chemical immersion tests, microbiological simulation tests, and in-situ tests. Then, non-experimental evaluation methods were summarized, such as numerical modelling and data science. After that, the pros and cons were discussed and highlighted for various evaluation methods. It was concluded that none of the existing evaluation methods could adequately reproduce the MIC process with reasonably high practicality and a short evaluation duration. Future research is needed in the development of such an evaluation method.

Study on the oxidation and acidification characteristics of the sulfur-containing tailings material

For studying the mechanical properties of sulfur-containing tailings material in the acidification environment, the tailings material was soaked in H2O2 solution with different concentrations to simulate the oxidation and acidification of the tailings with different accumulation history. The change laws and mechanisms of its mechanical properties after oxidation and acidification were discussed, and through the PFC (particle flow code) mesoscopic discrete element analysis method, the connection between mesoscopic particles and its macroscopic properties was established. The experimental results show that the chemical immersion tests on tailings materials with a certain ratio of hydrogen peroxide to concentrated sulfuric acid can well simulate the joint action of oxidation and acidification, so as to simulate the tailings with different accumulation history. Under the action of oxidation and acidification, the physical and mechanical properties of tailings material are mainly affected by the particle size and contact characteristics. The angle of internal friction decreases, influenced by the reduction of particle size, while the change of cohesive force is greatly correlated with both of the two factors. The shear modulus under different porosity and friction coefficients is basically the same, but the increase of porosity or the decrease of mesoscopic particle friction coefficient will greatly weaken its shear capacity, that is, its mesoscopic particle compactness and contact characteristics have an important impact on the macroscopic mechanical properties of tailings.

Influence of Aging Heat Treatment on Pitting Corrosion Resistance of Martensitic Stainless Steel

In this research is to study the influence of the aging heat treatment on the pitting corrosion resistance of martensitic stainless steel (MSS), where a number of specimens from martensitic stainless steel were subjected to solution treatment at 1100 oC for one hour followed by water quenching then aging in the temperatures range (500-750) oC for different holding times (1,5,10,15&20) hr. Accelerated chemical corrosion test and immersion chemical corrosion test were performed on samples after heat treatment. The results of the research showed that the pitting corrosion resistance is significantly affected by the aging temperature. Where found that the aging samples at a temperature of 500 °C have the highest rate of corrosion which may be due to an increase in the ratio of the Delta type ferrite (δ-ferrite) and very soft precipitates from other phases of heterogeneous form in the basic martensitic phase; which leads to increased corrosion rate, whereas aging samples in the temperature range (550–650) °C have the smaller rate of corrosion values, this is due to the high volumetric ratio of remaining austenite. The aging samples at temperatures above 650 °C show an average corrosion rate. It was also found that the type of pits resulting from both the chemical corrosion tests and their shape were not related to the ferrite type and the carbides present in the microstructure

The fabrication composite material of bimetallic micro/nanostructured palladium–platinum alloy and graphene on nickel foam for the enhancement of electrocatalytic activity

A composite of micro/nanostructured palladium–platinum alloy, reduced graphene oxide and polydopamine on nickel foam was obtained by a chemical immersion method and anneal method with high catalytic efficiency for the ethanol oxidation.

Enhanced osteogenic activity and antibacterial performance in vitro of polyetheretherketone by plasma-induced graft polymerization of acrylic acid and incorporation of zinc ions.

Polyetheretherketone (PEEK) has been widely used in the fields of orthopedics and trauma, but weak osteointegration and bacterial infection affect its long-term stability and repair effects. Surface modification is an effective way to improve the osteogenic and antibacterial activity of PEEK implants. In the present study, a layer of acrylic acid (AA) polymer coating loaded with zinc ions (Zn2+) was constructed on the surface of PEEK (PEEK-AA-Zn) using a strategy of combining plasma-induced graft polymerization with a chemical immersion technique. Successful construction of the AA coating remarkably enhanced the hydrophilicity of PEEK, and effectively loaded and released Zn2+. In vitro cell culture using MC3T3-E1 preosteoblasts showed that the Zn2+ released from PEEK-AA-Zn promoted cell proliferation and elevated gene expression levels of alkaline phosphatase (ALP), osteocalcin (OCN) and bone sialoprotein (BSP). Antibacterial tests revealed that PEEK-AA-Zn efficiently inhibited the proliferation of Staphylococcus aureus (S. aureus). These results suggest that the combined method of graft polymerization and ion incorporation endows PEEK with excellent osteogenic and antibacterial activity, which provides a wide range of possibilities for developing PEEK implants with multifunctional properties for bone tissue repair.

Rheological Modification for Asphaltic Materials Using a Mixture (Poly carbonate: Poly Methyl Methacrylate) and Microwave Radiation

Obtaining asphalt that suits the nature of the countries it is used in, is of great importance. Asphalt constitutes an important component in the paving of roads, mastic and flattening substance. This study was included the modification of the asphaltic material by the use of a mixture of polycarbonate and polymethyl methacrylate after crushed to obtain low molecular weight. The study included two paths: In the first asphaltic materials was treated with different percentages of a mixture in the presence of anhydrous aluminium chloride (0.06%of weight) as a catalyst for this reaction. The mixture was heated at 150° for 30 minutes. In the second path, the process of mixing was performed with the existence of a 360 watt microwave radiation for 15 minutes. The process of mixing was repeated in the presence of sulphur (1% of weight) instead of anhydrous aluminium chloride and under the same conditions. Properties of the original and modified asphalts were determined, and this included the measurement of ductility, penetration, softening point, penetration index and calculating the percentage of separated asphaltenes. Additionally, Marshal test, chemical Immersion test and aging were measured for some of the samples. Good samples that can suit Iraq's climate were obtained from this study.

Fabrication of Anti-Reflective Surface with Superhydrophobicity/High Oleophobicity and Enhanced Mechanical Durability via Nanosecond Laser Surface Texturing.

In this work, anti-reflective surface with superhydrophobicity/oleophobicity and enhanced abrasion resistance was fabricated on steel alloy surface. Two different surface patterns (i.e., parallel microgrooves and spot arrays) were created by nanosecond laser ablation and chemical immersion. The surface micro/nanostructure, spectral reflectance, wettability, and abrasion resistance of all the samples were determined. The experimental results showed that the laser-chemical treated surfaces exhibited much lower spectral reflectance and significantly enhanced surface integrities compared with the untreated surface. Firstly, the contact angles of water, glycerol, and engine oil on the laser-chemical treated surfaces were increased up to 158.9°, 157.2°, and 130.0° respectively, meaning the laser-chemical treated surfaces achieved both superhydrophobicity and high oleophobicity. Secondly, the laser-chemical treated surface showed enhanced abrasion resistance. The experimental results indicated that the spectral reflectance of the laser-chemical treated surfaces remained almost unchanged, while the laser-chemical treated surface patterned with parallel microgrooves sustained superhydrophobicity with a water contact angle of 150.2° even after more than one hundred abrasion cycles, demonstrating the superior mechanical durability. Overall, this fabrication method has shown its effectiveness for fabrication of multifunctional metal surface integrating the surface functionalities of anti-reflectivity, superhydrophobicity/high oleophobicity, and enhanced abrasion resistance.

The influence of dendrite size on corrosion properties of Ti43.2Zr29.8Cu6.7Nb4Be16.3 amorphous matrix composites in NaCl solution

In this study, the influence of dendrite size on corrosion behavior of Ti43.2Zr29.8Cu6.7Nb4Be16.3 in 3.5 wt. % NaCl solution was examined. These amorphous matrix composite alloys were found to contain 50 ~ 57 vol. % dendrites with size ranging from 3.21 to 32.28 μm. The electrochemical measurements revealed the corrosion resistance decreased as dendrite size increased. The alloys with the smallest dendrite size and 3 mm diameter exhibited the optimum corrosion resistance with the lowest corrosion current density estimated to 3.6(±0.5) × 10−8 A/cm2. And the corrosion behavior of preferentially dissolves was observed at the position of amorphous matrix. A possible corrosion mechanism associated with the selective dissolution was proposed. X-Ray photoelectron spectroscopy (XPS) analysis revealed formation of different oxides on specimen surfaces, causing discrepancies in corrosion resistance of the alloys. The chemical immersion tests further confirmed the corrosion behaviors. Overall, these data look promising for future new application of BMGMCs.

Oxidation resistance of Al2O3/SiO2 nanocomposite coating on hot-dip galvanized steel deposited by chemical immersion and sol-gel coating

A protective coating against oxidation of hot-dip galvanized (HDG) steel was developed using a solution-based route and its oxidation protectiveness during hot-stamping was evaluated. An Al2O3/SiO2 nanocomposite coating of approximately 500 to 700 nm was developed and successfully processed on a HDG SGC400 steel via a chemical immersion and sol-gel dip coating method. Oxidation tests at 900 °C show that oxidation of the HDG SGC400 steel is effectively suppressed by the Al2O3/SiO2 nanocomposite coating, signifying its potential as a protective coating for HDG press hardening steel. The phase transformation of Al2O3/SiO2 nanocomposite coating at 900 °C was also investigated. Although cracks form inevitably, the Al2O3/SiO2 nanocomposite coating is stable at 900 °C. Specially, the thickness of the composite coating changes slightly and ZnO is confined in the composite coating via the formation of Zn2SiO4 nanoparticles. Finally, this chemical immersion and dipping route to form a nanocomposite oxide coating is in line with the continuous hot-dip galvanizing line for steel industry.

Self-cleaning material based on superhydrophobic coatings through an environmentally friendly sol–gel method

Recently, there has been increasing interest in developing artificial superhydrophobic surfaces, especially in the field of self-cleaning application. However, the poor robustness and high-cost preparation of these surfaces have always been some issues for their industrial development. Herein, we describe an environmentally friendly way to prepare stable, robust, and transparent superhydrophobic coatings through the deposition of a rough substructure of TiO2 film followed by chemical modification using octadecyltrichlorosilane (OTS), a fluorine-free organic silane. The as-prepared coatings exhibited a great superhydrophobic property and ultralow adhesion (with a static water contact angle of 158 ± 2° and sliding angle of 4 ± 1°). It was found that the superhydrophobic coatings can still maintain good performance after UV irradiation, chemical immersion, and physical abrasion. More importantly, the coated surfaces showed an excellent self-cleaning ability against dirt particles after rinsed with water droplets.

Zr4+-Doped Anatase TiO2 Nanotube Array Electrode for Electrocatalytic Reduction of L-cystine

A Zr4+-doped anatase TiO2 nanotube array electrode was prepared using a process that included Ti anodizing, chemical immersion, and heat treatment. The compositions, microstructure, and electrochemical properties of the prepared electrodes were characterized. The results show that Zr4+ was successfully introduced into the TiO2 nanotube array electrodes. Because Zr4+ was doped into the crystal structure of the TiO2and replaced a part of Ti4+ to form more oxygen vacancies and Ti3+, the electrocatalytic activity of the prepared electrodes, for the reduction of L-cystine, was significantly improved.

Laser-chemical treated superhydrophobic surface as a barrier to marine atmospheric corrosion

A time efficient and cost-effective laser-based surface texturing technique combining nanosecond laser ablation and chemical immersion treatment was developed for steel alloy to achieve enhanced corrosion resistance in marine atmospheric environment. Three different surface patterns were created by nanosecond laser ablation and the laser patterned samples were subsequently immersed in 1H,1H,2H,2H-perfluorooctyl silane (FOTS) solution to tune surface chemistry. Dual-scale surface structure was formulated on the laser-chemical treated surface, as confirmed by the scanning electron microscopy (SEM) and confocal laser scanning microscope analyses. X-ray photoelectron spectroscopy (XPS) analysis was conducted to validate that desired surface chemistry was achieved on the laser-chemical treated surface. The effect of surface pattern on several key surface functionalities, including surface wettability, corrosion resistance and chemical stability was systematically presented in this work. Firstly, it was demonstrated via wettability measurements that the laser-chemical treated surface achieved superhydrophobicity with a water contact angle of 158.9°. Secondly, electrochemical and NaCl deliquescence tests were conducted to determine the corrosion resistance of the laser-chemical treated surfaces in marine atmospheric environments. It was confirmed that the laser-chemical treated surface can prevent marine atmospheric corrosion induced by salt deliquescence. Furthermore, it was revealed by electrochemical test that the laser-chemical treated superhydrophobic surface exhibited distinctly better anti-corrosion performance. The experimental results showed that the corrosion rate for the laser-chemical treated surface with microgroove pattern is approximately 5.4% of the corrosion rate for the untreated surface, indicating significant improvement of corrosion resistance for the laser-chemical treated surface. Thirdly, the high water contact angle of 151.0° sustained on the laser-chemical treated surface after electrochemical tests helped confirm the improvement of its chemical stability in corrosion medium. These experimental findings clearly demonstrate the developed nanosecond laser-chemical treatment method can be very effective for fabrication of stable superhydrophobic metal surface as a barrier to marine atmospheric corrosion with enhanced corrosion resistance.

Effect of Ultraviolet Radiation on Candida albicans Biofilm on Poly(methylmethacrylate) Resin.

To investigate the effect of 254-nm ultraviolet light on the viability of Candida albicans biofilm on poly(methylmethacrylate). Poly(methylmethacrylate) specimens (1 cm × 1 cm × 1 mm) were placed in 6-well culture plates. Each well contained 8 ml of 104 colony forming units/milliliter of C. albicans ATCC90028 and Sabouraud dextrose broth. Plates were incubated at 37°C for 24 hours. Specimens were then divided into 11 groups (n = 4): no treatment control groups, 3.8% sodium perborate immersion for 5 minutes (PP5m) and for 12 hours (PO12h), and 6 groups exposed to ultraviolet light for 5, 15, 30, 60, 120 or 300 seconds separately using UVP XX-15S series lamps. After sonication, cell suspensions were plated, and colony-forming units were counted. The relationship between survival of C. albicans and ultraviolet light irradiation energy exposure was analyzed and compared to the survival of sodium perborate groups. The effect of disinfection treatments and ultraviolet light energy exposure on C. albicans survival was analyzed with ANOVA (alpha = 0.05). There was a significant decrease in C. albicans survival with increasing ultraviolet light energy exposure (p = 0.00001, p < 0.05) Survival vs. immersion exposure time analysis of chemical disinfection showed no survival of C. albicans in groups PP5m and PO12h. C. albicans in the UV 300s group with energy of 210 mJ/cm2 (71 CFU/ml) showed a statistical difference from that of two chemical immersion groups (PP5m, PO12h = 0 CFU/ml) (p = 0.00001, p < 0.05). Ultraviolet 254 nm irradiation demonstrated a significant inhibition of C. albicans survival on poly(methylmethacrylate) samples. Ultraviolet light exposure of 300 seconds inhibited the survival of C. albicans close to the level of 3.8% sodium perborate treatment.

Superhydrophobic surface based on nano-engineering for enhancing the durability of anticorrosion

ABSTRACT Here, a new class superhydrophobic surface based on nano-engineering was proposed and prepared to improve the durability of corrosion protect. Moreover, the durability of anticorrosion was evaluated by the Tafel polarization curves and electrochemical impedance spectroscopy under various damages of mechanical abrasion, chemical immersion and cool/thermal treatment. The superhydrophobic surface based on nano-engineering still showed excellent anticorrosion performance, such as low corrosion current (∼10−10 A cm−2), large polarization resistance (>150.0 MΩ cm2) and low corrosion rate (∼10−6 mm/year). The good durability was attributed to the special nano-engineering with low surface roughness and surface energy. The work provides a new method to improve the durability of the superhydrophobic surfaces for application in anticorrosion technology.

Copper alloying content effect on pitting resistance of modified 00Cr20Ni18Mo6CuN super austenitic stainless steels

The effect of Copper (Cu) on pitting resistance of modified 20Cr-18Ni-6Mo-0.2 N Super austenitic stainless steels was studied by chemical immersion, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. It has been found that Cu affects on the average weight loss rate, the number of pitting pits, pitting pit surface area, passive film surface quality, charge transfer resistance and nanostructure of passive film. The passive film of the super austenitic stainless steels in chloride solution has three layers. This study provides a theoretical basis for the study of stainless steel used in harsh marine media.

Photoelectrocatalytic degradation of sulfadiazine by Ag3PO4/MoS2/TiO2 nanotube array electrode under visible light irradiation

Effective decomposition of antibiotic sulfadiazine (SD) by Ag3PO4/MoS2/TiO2 nanotube array electrode was investigated. TiO2 nanotube arrays (NTAs) were modified with MoS2 nanosheets and Ag3PO4 nanoparticles by photo-assisted electrochemical deposition and chemical immersion method. The as prepared electrode was characterized using field emission scanning electron microscopy (FESEM), high-resolution transmission Electron Microscope (HRTEM), X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, ultraviolet-visible diffuse reflectance spectroscopy (UV–vis DRS), and photoelectrochemical measurements. The results demonstrated that the Ag3PO4/MoS2/TiO2 NTAs exhibited higher photoelectrocatalytic (PEC) activity during SD degradation under visible light excitation. The results of electron spin resonance (ESR) indicate that a large amount of active superoxide radicals and a small amount of hydroxyl radicals could be generated by Ag3PO4/MoS2/TiO2 NTAs under visible light. Five intermediates were detected by usinghigh performance liquid chromatography-mass spectrometry (HPLC-MS) during sulfadiazine degradation. Based on the theoretical reaction sites of active species and intermediates, the possible pathway of SD degradation by Ag3PO4/MoS2/TiO2 was proposed.

Nanosecond pulsed laser processing turns engineering metal alloys antireflective and superwicking

In this work, superwicking and antireflective properties are achieved on engineering metal surfaces by creating a surface pattern using a high energy nanosecond pulsed laser followed by a chemical immersion treatment. The high-energy nanosecond pulse laser scans the metal surface in air. Subsequently, the laser-textured surface is further treated by immersion in a 3-cyanopropyltricholosilane reagent. As a result of these two processes, microgrooves with micro- and nano-scale surface features are generated on the metal surface. Due to the created surface structure and favorable surface chemistry, water sprints uphill defying the gravity. The fast self-propelling movement of water is due to the supercapillary effect of the surface microchannel and the superhydrophilic surface nitrile group. The wicking effect on the processed surface follows the classical square root of time dependence. The processed surface shows good antireflective properties in the visible and infrared spectrum. Surface features, surface chemistry, wettability, surface reflectivity and wicking behavior are measured on AA6061 and Ti-6Al-4V specimens through Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), contact angle goniometer, UV-VIS-NIR spectrometer and high-speed camera, respectively.

In-vitro and in-vivo evaluation of strontium doped calcium phosphate coatings on biodegradable magnesium alloy for bone applications

The objective of the present work was to investigate the in-vitro and in-vivo performance of strontium doped calcium phosphate (Ca-Sr-P) coatings on ZK60 magnesium (Mg) alloy for bone applications. A chemical immersion technique was employed to develop Ca-Sr-P coating on biodegradable Mg alloy. Surface morphology, chemical composition, phase, mechanical properties, wettability, in-vitro corrosion, cytocompatability, in-vivo degradation and biocompatibility of Ca-Sr-P coatings were studied. The Ca-Sr-P coating (~20 µm) exhibited a dense, crystalline, uniform, and crack-free surface. In-vitro studies revealed that the coating improved the corrosion resistance of Mg alloy and enhanced bioactivity. The surface coating also promoted the adhesion, proliferation, and osteogenic markers expression of MC3T3-E1 cells. The coating lowered the degradation rate in-vivo compared with Mg alloy. Higher bone formation and better ossteointegration was found around the coating than the Mg alloy after 4 weeks of implantation in a rabbit model. Thus, the Ca-Sr-P coating with a reduced degradation and improved biocompatibility could be used in Mg-based orthopedic implant applications.

Fabrication of mechanically enhanced superhydrophobic surface using nanosecond laser-based high-throughput surface nanostructuring (nHSN)

Abstract In this work, we conduct a systematic experimental investigation of surface integrity for steel and aluminum alloys processed via nanosecond laser-based high-throughput surface nanostructuring (nHSN) process. nHSN surface morphology and surface chemistry are first experimentally characterized, and the results show that surface nanostructure with proper surface chemistry is generated due to the combined effect of chemical etching and attachment of functional groups of low surface energy. Desired surface wetting behavior is achieved using a proper silane reagent during the nHSN chemical immersion treatment phase, while surface nanostructure can be finely modulated by adjusting the laser processing parameters. nHSN nanostructures with fluorosilane chemistry exhibit strong capability to repel water, leading to superhydrophobicity achieved on two important engineering metal alloys, namely steel and aluminium alloys. It is further experimentally demonstrated that the microhardness and anti-corrosion performance of the nHSN surface can be significantly enhanced compared with the untreated surface, indicating that the nHSN process is very effective for enhancing the mechanical strength and corrosion resistance of these important metal alloys. These results show that nHSN simultaneously creates random nanostructures, attains desirable surface chemistry and enhances surface integrity over large-area metal alloy surfaces.

Scanning Electron Microscopy Study of Di-Calcium Phosphate Dehydrate Coatings on Magnesium Substrates for Potential Use in Orthopaedic Implants

Magnesium has attracted considerable medical interest due to its mechanical properties being similar to bone. In addition, magnesium is also biocompatible and biodegradable, which makes it an ideal candidate for biodegradable orthopaedic implants. However, magnesium’s high corrosion rate in body fluids makes it an unsuitable material for the manufacture of implants. The present study investigates a straightforward chemical immersion technique that deposits di-calcium phosphate dehydrate (DCPD) coatings onto magnesium substrates to increase their corrosion resistance to body simulated fluids like phosphate buffer saline solution and Ringer’s solution. Scanning electron microscopy revealed the coating structures and morphologies were characterised by flower-like surface feature that were resistant to both body simulated fluids. Thus, indicating the coatings could significantly reduce magnesium corrosion rates in the body environment.