Service Life Of Coatings Research Articles

Terahertz Nondestructive Measurement of Heat Radiation Performance of Thermal Barrier Coatings Based on Hybrid Artificial Neural Network

Effective control of the micro- and nanostructure of thermal barrier coatings is essential to enhance the thermal radiation performance of the coating, which helps to determine the remaining service life of the coating. This paper proposed a method to measure the radiation properties of thermal barrier coatings by terahertz nondestructive testing technique, using APS-prepared thermal barrier coatings as the object of study. Radiative properties were a comprehensive set of properties characterized by the diffuse reflectance, transmittance, and absorptance of the thermal barrier coating. The coating data in actual service were obtained by scanning electron microscopy and metallographic experiments, and the data were used as the simulation model critical value. The terahertz time-domain simulation data of coatings with different microstructural features were obtained using the finite-different time-domain (FDTD) method. In simulating the real test signals, white noise with a signal-to-noise ratio of 20 dB was added, and fast Fourier transform (FFT), short-time Fourier transform (STFT), and wavelet transform (WT) were used to reduce the noise and compare their noise reduction effects. Different machine learning methods were used to build the model, including support vector machine algorithm (SVM) and k-nearest neighbor algorithm (KNN). The principal component algorithm (PCA) was used to reduce the dimensionality of terahertz time-domain data, and the SVM algorithm and KNN algorithm were optimized using the particle swarm optimization algorithm (PSO) and the ant colony optimization algorithm (ACO), respectively, to improve the robustness of the system. The K-fold cross-validation method was used to construct the model to improve the adaptability of the model. It could be clearly seen that the novel hybrid PCA-ACO-SVM model had superior prediction performance. Finally, this work proposed a novel, convenient, nondestructive, online, safe and highly accurate method for measuring the radiation performance of thermal barrier coatings, which could be used for the judgment of the service life of thermal barrier coatings.

Research on service life prediction and decorative properties of acrylic paint in Vietnam's marine atmosphere by acceleration test

Vietnam is located in a tropical climate zone, especially coastal climates that quickly destroy coating materials that protect steel structures. Therefore, the service life of coatings is always of concern to manufacturers and users. This article presents the results of surveying changes in gloss, color and service life prediction of acrylic paint by accelerated tests, that have simulated according to marine tropical conditions, which are correlated with the atmosphere at Dam Bay station (Hon Tre Island, Nha Trang city, Khanh Hoa province, Vietnam). Gloss is determined according to ISO 2813:2014, and color change is determined according to standard ASTM E308-12. The service life of the acrylic paint system is determined according to standard GOST 9.401-2018. Calculation results based on accelerated test data show that the corrosion time of the acrylic paint system reaches Ri 3 (according to ISO 4628-3:2016 assessment), the service life of acrylic paint Tar 5366 is 2.91 years, and acrylic paint AR-752 is 2.66 years.

Application of AIE luminogen-loaded core–shell fibers in self-warning and self-healing polymer coatings with enhanced corrosion resistance

Aggregation-induced emission (AIE) materials have been used for non-destructive visual detection of cracks and damages to prevent the final structural failure and increase the service life of coatings. In this study, a self-warning and self-healing core–shell fiber is synthesized for developing AIE composite coatings. In these core–shell fibers, a mixture of hmethylene diisocyanate (HDI) and tetraphenylethylene (TPE) is used as core constituent, and polyacrylonitrile (PAN) is used for preparing the shell, which are continuously wrapped with a high loading rate through coaxial electrospinning technology. The parameters of electrospinning process are optimized to achieve core–shell fibers with smooth surface and average diameter of 100 ± 50 nm. The composite coating reveals effective fluorescence in case of cracks in a corrosive environment. The maximum self-healing efficiency of the fiber coating is 94.8 % after soaking for 120 h. The introduced composite coating paves the way for improving the safety and reliability of critical engineering components.

Active/passive protection and anti-UV waterborne epoxy coatings based on low defect functionalized PDA-GO-CeO2 material for excellent corrosion control

In the marine environment, besides external damage and internal defects, ultraviolet (UV) radiation is also a pivotal factor affecting the stable properties of coatings. Improving the anti-UV aging and active protection properties is beneficial to prolong the service life of coatings. Herein, the PDA-GO-CeO2 composite material is obtained through a facile stepwise growth of polydopamine (PDA) and CeO2 on GO nanosheets and further preparing a multifunctional anti-corrosion PDA-GO-CeO2-EP coating. As expected, composite coating displays strong adhesion force (6.9 MPa) and tensile strength (21.1 MPa), profiting from the enhanced crosslinking density and interface structure caused by PDA-GO-CeO2 and resin matrix interaction. Since low defect functionalized PDA-GO-CeO2 constructs the reinforced physical barrier, the anti-corrosion ability of PDA-GO-CeO2-EP coating (109.7 Ω·cm2) is more dependable than those of EP (106.7 Ω·cm2), GO-EP coating (108.8 Ω·cm2) and PDA-GO-EP (109.1 Ω·cm2) coatings after immersing in 3.5 wt.% NaCl solution for 100 d. Thanks to the synergistic effect of PDA/CeO2, the active protection performance of PDA-GO-CeO2-EP coating is endowed, which is further proved through the in situ scanning vibrating electrode technique (SVET). Following the UV aging treatment, PDA-GO-CeO2-EP coating shows minor gloss loss (20.4 %) and better adhesion force (4.3 MPa). Furthermore, the resistance value of PDA-GO-CeO2-EP coating is 7.03 × 106 Ω cm2 after 30 d immersion in saline solution, which is 242 times greater than that of EP coating (2.90 × 104 Ω cm2). This dependable performance of PDA-GO-CeO2-EP coating comes from the reflection, refraction, and absorption of UV rays by nanoscale CeO2 particles. Consequently, this work offers a simple and promising strategy for fabricating multifunctional long-term protection coatings, thus hopefully extending the service life of marine engineering equipment.

Microstructure, mechanical properties and wear behaviors of TiN/Ti composite coating on laser surface textured Ti6Al4V alloy fabricated by MHz picosecond laser surface alloying

Ceramic-reinforced metal matrix composites (MMCs) coating fabricated by laser surface melting effectively improves the surface mechanical and wear properties of titanium alloys. However, power of several hundred watts is generally used in traditional laser processing, which introduces excessive heat input and leads to thermal deformation and thermal effects, resulting in cracks and reducing mechanical properties and service life of coatings. In order to improve the microhardness and anti-wear properties of Ti6Al4V alloy and extend the service life, a picosecond laser (ps-laser) with a power of 23 W and repetition rate of 19 MHz was utilized to fabricate the uniform and crack-free MMCs coating (TiN/Ti) by melting TiN powders on the textured Ti6Al4V surface. Three different textures with different texture densities and depths were used to evaluate their effects on coatings. Results showed that the reinforced TiN phase was in the form of fine dendrites with an average secondary dendrite arm spacing of 0.84 µm. The microhardness and the anti-wear properties were both inversely proportional to the texture densities because of controlling the volume fraction of TiN in the coating. The microhardness of the sample with greatest microhardness increase was significantly improved from 355 HV0.5 (base material) to 1000 HV0.5 due to the addition of the TiN phase. The sample with a texture density of 5% showed the best anti-wear properties (about 22 times that of the substrate) due to the effective suppression of three-body abrasive wear.

A novel cerium organic network modified graphene oxide prepared multifunctional waterborne epoxy-based coating with excellent mechanical and passive/active anti-corrosion properties

Effectively reducing microdefects and endowing coatings with active protection are critical factors in prolonging the service life of coatings. Herein, a novel ceria nanoparticle decorated cerium organic network (GO-CN/CON-U) is in-situ prepared on graphene oxide (GO) via a simple one-step method. Then, a multifunctional coating is obtained by introducing GO-CN/CON-U into the epoxy resin matrix. The coating surprisingly exhibits exceptional mechanical properties and hydrophobicity attributing to the optimized crosslinking degree, compactness, and toughness due to the interaction between composite materials and epoxy resin, while its sustained anti-corrosion performance (around 109 Ω·cm2) also displays three orders of magnitude higher than that of pure epoxy coating (less than 106 Ω·cm2) even after 60 d of immersion in the aggressive media. An active protective mechanism was further proposed according to the UV–Vis and microelectrochemical test results, revealing that a shielding film can be promptly formed on the surface of Q235 steel when damage occurs against the attack of aggressive ions due to the release of Ce3+/Ce4+ and organic inhibitors from GO-CN/CON-U under acidic responsiveness. In brief, the present work provides a simple but attractive strategy for the preparation of long-lasting multifunctional protective coatings.

A multifunctional and long-term waterborne anti-corrosion coating with excellent ‘hexagonal warrior’ properties

Environmentally friendly waterborne coatings tend to form polar pathways due to more hydrophilic groups, resulting in poor coating corrosion resistance and reduced coating service life. The anisotropic Janus is used as a filler for waterborne epoxy (WEP) coatings to reduce the number of hydrophilic groups and improve interface compatibility by cross-linking the hydrophilic end with the resin; at the same time, the hydrophobic groups are used to improve the water resistance of the coating. In this paper, we synthesized sheet-like silica Janus (JNS) materials by interface-induced self-assembly via sol–gel reaction in oil-in-water emulsions to prepare novel water-based JNS/WEP anticorrosion coatings. The excellent corrosion resistance of JNS/WEP coatings is explained by the fact that the hydrophilic end of JNS reduces internal defects in the coating and enhanced interfacial interaction; the hydrophobic end improves the water resistance of the coating. Similarly, the physical barrier advantage of flake JNS is brought into play to reduce the high availability of water and oxygen, inhibit electrochemical corrosion on the surface of carbon steel and form a passivation film; the active group at the hydrophilic end of JNS can be chelated with Fe3+ for active protection by synergistic. Among them, immersed in 3.5 wt% NaCl solution for 130 days, the impedance modulus of 1.0 % JNS/WEP coating is 2 orders of magnitude higher than that of WEP coating, up to 2.59 × 1010 O cm2. Therefore, it exhibits outstanding anti-corrosion performance under multiple synergistic protection.

Wear Mechanism and Life Map Construction of Nitride Coatings on Different Substrates

The sliding wear and failure behaviors of CrN and AlTiN coatings on high speed steel (HSS) and cemented carbide (WC-Co) were investigated on a reciprocating test machine under different normal forces (30–120 N). The wear mechanism was explored based on the analysis of coefficient of friction (CoF), wear and damage of coating. Then, the coating service life maps were established and the factors affecting the coating life were explored. The results indicated that the bonding strength of coatings to the WC-Co substrate were larger than those to the HSS substrate. The CoFs of CrN fluctuated during the wear process, while CoFs of AlTiN coatings were closer to those of the uncoated substrates. The wear depths of coated samples were smaller than those of uncoated substrates. The wear depths were small when the coatings worked and then increased with the number of cycles and the normal forces. For the CrN coatings, they had longer service life under smaller normal forces than under the large forces. Under small forces, an adhesion layer derived from the wear debris was formed on the coating surface to reduce the wear at the beginning of the test, after that the main failure mechanism was abrasive wear and delamination. Under large forces, the main failure mechanism was spallation. For the AlTiN coatings, the main failure mechanism was spallation on the HSS substrate; however, on the WC-Co substrate it was adhesive and abrasive wear. The coatings (CrN and AlTiN) on WC-Co had longer service life under various normal forces than on the HSS. CrN coating has the better wear-resistance than AlTiN coatings.

A two-dimensional nanocontainer based on mesoporous polydopamine coated lamellar hydroxyapatite towards anticorrosion reinforcement of waterborne epoxy coatings

Two-dimensional (2D) nanocontainers provide exciting opportunities in anticorrosion application through a skillful combination of delivery functionality for corrosion inhibitors and barrier property of lamellar materials. Herein, we used a versatile emulsion-induced approach to synthesis sandwich-like 2D nanocontainers based on mesoporous polydopamine (PDA) heterostructures on ultrathin bio-ceramic hydroxyapatite (HA) nanosheets. Triblock copolymer and 1,3,5-trimethyl benzene (TMB) synergistically promote the formation of well-defined mesoporous structure. The porous PDA not only provides large amount of contact interface for embedding benzotriazole (BTA), but also serves as another important corrosion inhibitor to achieve active protection effect. In addition, rich functional groups in PDA structure ensure the fine interface compatibility between lamellar HA and waterborne resin, leading to the improvement in terms of coating barrier performance. In comparative evaluation, the composite coatings containing BTA-loaded nanocontainers (1 wt%) exhibit high impedance value (Zf=0.01 Hz) in 3.5 wt% NaCl solutions for 60 days, indicating the long-term anticorrosion properties. Meanwhile, local electrochemical impedance technology proves nanocontainers with BTA loaded obviously inhibited the corrosion reactivity in corrosive microregions. This work puts new insights into designing functional anticorrosion coatings based on the surface construction on 2D materials, which has potential application for improving coating service life in marine environment.

Optimization of intrinsic self-healing silicone coatings by benzotriazole loaded mesoporous silica

Multifunctional intrinsic self-healing polymers (ISP) are gaining increasing attention these days, and many studies have been devoted to solving the conflict between achieving high mechanical polymer strength and active polymer chain diffusion. In this research, we developed an optimized self-healing composite coating by adding Benzotriazole (BTA) loaded nano silica (SiO2@BTA) to a dynamic cross-linked Polydimethylsiloxane (PDMS) network，which allows substantial and fast healing of the material integrity upon damage due to the hydrogen interaction between urea and BTA. BTA leaching tests demonstrated a longer release profile during the coating service life and corrosion tests in a 3.5 wt% NaCl aqueous solution indicated that the SiO2@BTA modified PDMS coating shows enhanced corrosion protection of carbon steel upon coating damage. Moreover, after addition of SiO2@BTA, the material failure strength increased from ~1.5 MPa to ~5.5 MPa, and the healing efficiency increased from ~59% to ~90% for 24 h healing at room temperature. Above all, this research provides an intrinsic self-healing coating design method to improve the mechanical strength and the self-healing ability of the ISP as well as enhancing the coating's corrosion protection ability.

Potential Use of the Pigments from Scytalidium cuboideum and Chlorociboria aeruginosa to Prevent ‘Greying’ Decking and Other Outdoor Wood Products

UV-light degradation of wood is one of the top reasons for consumer replacement of outdoor wooden structures. This type of degradation is seldom mechanical, and is instead often motivated by loss of aesthetics (graying). There are numerous commercial products available on the market that deal with this loss of color, many of which contain added pigments to ‘rejuvenate’ or ‘revitalize’ greyed wood. These pigments are almost uniformly synthetic. In contrast, pigments from wood decay fungi (spalting), which have been used in woodworking since the 1400s (intarsia), have remarkable optical (UV-light resistance) properties due to their naphthoquinonic configuration. In recent years the pigments made from these fungi have been extracted and tested across numerous substrates, from solar cells to textile dyes. In this work, researchers extracted pigments from Scytalidium cuboideum (red pigmentation) and Chlorociboria aeruginosa (blue-green pigmentation), solubilized the pigments in raw linseed oil, and tested the resulting solution on samples of Douglas-fir (Pseudotsuga menziesii) and western white pine (Pinus monticola). These mixtures were compared against a ‘stain and coat’ treatment (utilizing an aniline stain and coated with raw linseed oil), raw linseed oil, and untreated wood. The wood samples were then placed in an accelerated weathering machine (Q-UV) following the ASTM G154 standard, for 500 and 1000 h. The results showed that while no visible color change occurred to the wood when the pigmented oil was applied, the red pigment oil significantly lowered the coating degradation for both wood types at an exposure of 500 h. The results show the potential applications for fungal pigments in the wood coating industry, as it offers an increased coating service life. As there is a shift to renewable products, the pigments from wood decay fungi show potential as additives for wood coatings.

Electron-Microscopic Study of the Porosity and the Morphology of Chemical Nickel Coatings

The results of determining the porosity of chemical nickel coatings, which were obtained using electron microscopy and an image processing system, are reported. The procedure allows pores more than 10 nm in diameter to be detected. Data on changing the porosity of chemical nickel coatings subjected to full-scale tests in a sea atmosphere are obtained. A three-stage failure mechanism of cathode coatings is suggested. The service life of coatings is determined.

Stable slippery coating with structure of tubes and pyramids for inhibition of corrosion induced by microbes and seawater

Corrosion induced by microorganisms and seawater can accelerate the failure of metals. To inhibit the corrosion process, in this work, an aluminum oxide coating with tubes-pyramids structure and SLIPS (AO-TP-SLIPS) is fabricated by employing a three-step method, which includes anodizing of Al, fluorination modification and lubricant infusion. To this end, the AO-TP-SLIPS coating affords stable mechanical properties and high corrosion-resistance against microorganisms and seawater. The pyramids structure of the AO-TP-SLIPS surface forms a barrier and slows down the consumption of the lubricant in the tubes, which is one of the key reasons for the improved corrosion resistance. The electrochemical measurements show that the AO-TP-SLIPS coating attains a corrosion current density of 3.39 × 10−12 A cm−2 in Pseudomonas aeruginosa broth and 3.17 × 10−13 A cm−2 in seawater. A high corrosion resistance of the AO-TP-SLIPS specimen retains for 36 days in seawater. This work demonstrates that a composite structure with tubes and pyramids can prolong the service life of coatings in an efficient way, which offers a theory basis for applications of SLIPS in marine environment.

A Review of Modern Assessment Methods for Metal and Metal-Oxide Based Primers for Substrate Corrosion Protection

Pigmented coatings developed for the corrosion protection of engineering alloys have been successful in the field of corrosion control, and thus are ubiquitous in application. Supporting this success are an array of methods to diagnostically assess these systems and measure their state of degradation. These methods assist the development of next generation coatings, in-service evaluation, and post-mortem analysis of performance. This review comprehensively explores these modern assessment methods, used to screen candidate corrosion prevention pigments, assess pigment protection efficiency, quantify overall pigment effectiveness, and/or predict coating service lifetime. Coating service life assessment is conducted based on the class of coating considered, as categorized by (1) chemical inhibition, (2) galvanic protection, (3) high impedance ion barrier, or a combination of these protection mechanisms. Exciting new in-situ and operando methods are growing in use to enable high fidelity measurement of chemical inhibitor release and deposition, such as micro and in-situ Raman spectroscopy and inductively coupled plasma atomic emission spectrometry (ICP-AES), to name a few. In the galvanic protection coating class, service life and the state of coating performance are now being quantified through methods such as galvanostatic pulse and accelerated cycle testing. Galvanic throwing power is assessed by scanning vibrating electrode technique (SVET), multi-electrode array (MEA), and scanning kelvin probe (SKP). The performance of high impedance ion barrier coatings has traditionally been understood through use of electrochemical impedance spectroscopy (EIS) and equivalent circuit modeling, which have been applied to all coating classes. Finite element analysis (FEA) models the combined effects of coating resistance, water layer thickness, and pigment potential on galvanic coupling and/or inhibitor species release as well. The development of effective corrosion prevention pigments and the in-service evaluation of their efficiency/effectiveness demands a broad collection of techniques. These methods now include new advances in thermodynamic modeling via chemical stability diagrams to assess pigment function in specific conditions, in-situ pH measurement, as well as energy dispersive (EDS) and x-ray photoelectron spectroscopic (XPS) analyses to determine elemental distribution and corrosion product formation. These techniques and more are explored in this review to document the state-of-the-art in the field.

Enhancement of photooxidative and corrosion resistance of epoxy/graphene water-based coatings on metallic substrate

Graphene nanoplatelets (GNPs) dispersed in low quantity in a waterborne epoxy resin enhance the coating anticorrosive properties and strongly contrast its photooxidative degradation. The study of the photooxidative behaviour monitored until 600 h, highlights a very relevant result from an applicative point of view. A low percentage of GNPs (1% by weight) determines a reduction in the increase of the carbonyl groups amount of 78 wt% compared to the unfilled sample. Furthermore, a low quantity of GNPs incorporated in the organic coating reveals a significant enhancement in the corrosion resistance, as demonstrated by electrochemical analysis. Results show that the greater the amount of GNPs the slower the absorption. Equivalent electrical circuits, by means of the “two-parallel-layer” model, are used to interpret the electrochemical behaviour, considering the complex nature of the waterborne and inhibitors free coating. A new promising strategy is foreseen for enhancing the performance of the coating service life.

Improving the service life of coatings during running-in

In work researches of phosphate coatings are conducted. By means of methods of mathematical modeling of contact interaction it is established that on wear of phosphate coatings the greatest influence renders their roughness. For decrease in wear of the running-in coverings applied to protection of steel products, the way on increase in service life of phosphate coatings is offered.

The use of stabilizers to improve the strength of the soil foundation of roads

This article describes the improvements, strength and deformation characteristics of loess soils used in the construction of road pavements with a stabilizer T-RRP. With the help of laboratory analyzes, a recommendation was developed on the use of stabilizers to improve the properties of loess soils used in the calculation of the pavement design. The use of stabilizers in road construction, in particular T-RRP, gives the following advantages: 1. Time savings during construction; 2. Saving ordinary building materials; 3. Shipping costs are eliminated; 4. Saving financial work afterwards; 5. Lack of repair later; 6. Minimal use of machines. 7. Minimal use of working force. The degree of adequacy of the project. Interested enterprises in the project are: LLC «FAYANTRANS», PEC «Avtomagistral», SRRCO «Uzavtoyul». The significance of the final results: the proposed methods of road construction, compared with traditional methods, gives the following advantages: the permissible load on roads constructed with the use of stabilizers in more than doubled compared to roads built in the usual way; reducing the thickness of the pavement by more than 25 % on the soil treated with stabilizers; built with the use of stabilizers roads increase their strength year after year; strength and stability of water-physical properties of clay soils used in the construction of roads, airfields, hydraulic structures; building with the use of stabilizers meets the requirements of ecology since it doesn’t produce harmful effect on groundwater. In addition to the advantages noted above, the use of stabilizers allows: increase the service life of coatings; get savings on maintenance and repair; increase the pace of construction; improve the quality of structures being built.

ELECTROLYTIC-PLASMA PROCESSING OF HIGH-TEMPERATURE NICKEL ALLOY CHS88U-VI AT ION-IMPLANT SURFACE LAYER MODIFICATION

The reliability and service life of gas pumping units (GPU) are largely determined by the presence, composition and quality of protective coat- ings created on the surface of the parts, especially on the most loaded ones - turbine blades. However, the service life of coatings containing mainly a complex of components of the Ni-Cr-Al-Y type is limited. The method of ion modification can significantly change the physical and chemical state of the surface and, as a result, increase the operating properties of the blade as a whole. Purposefully choosing atoms of dop- ing admixture and modes of irradiation using the ion implantation method, it is possible to provide high strength of the surface or subsur- face layer, change the concentration and spatial distribution of disloca- tions and other structural defects, ensure the formation of fine high- strength precipitates. Compared with traditional methods of chemical and thermal treatment, ion implantation can reduce the processing time by dozens of times and dramatically reduce the processing temperature. An important advantage of the method is the absence of an explicit phase boundary, a noticeable change in the size of the part. This circumstance allows to exclude the problems that have to be solved in the development of coating technol- ogy, such as providing adhesive strength, minimal impact on the strength properties of the part, compatibility with the base. The surface quality has a significant impact on the endurance limit and corrosion resistance of the GPU blades. The most promising method of surface treatment is electrolyte-plasma polishing (EPP) in neutral aqueous solutions of low concentration salts. As a result, the EPP from the surface removes several micrometers of the most rich in foreign inclusions and a polluted layer of metal, disappears directional anisotropy acquired during machining. The use of this meth- od before the hardening of ion implantation and the application of vacu- um ion-plasma coatings allows to combine in one operation degreasing, etching and activation of the surface, which in turn improves the effi- ciency of ion implantation, as well as improve the properties and adhe- sion of the coating to the base metal. The article presents the results of theoretical and experimental studies of the effect of EPP on ion-implantation modification of heat-resistant Nickel alloy CHS88U-VI by lanthanum ions. It is shown that the com- plex processing of the alloy, including EPP, ion implantation of lantha- num ions, post-implantation annealing can improve such characteristics of the alloy as microhardness, fatigue and long-term strength. Investigations of the modes of complex hardening treatment of alloy CHS88U-VI. The optimal modes of EPP, ion implantation, post-implan- tation annealing were selected. The results of the research are planned for the introduction of the production and repair of parts of the GPU.

Kinetic Analysis of Weakly ionized Plasmas in presence of collecting walls

Description of plasmas in contact with a wall able to collecting or emitting charged particles is a research topic of great importance. This situation arises in a great variety of phenomena such as the characterization of plasmas by means of electric probes, in the surface treatment of materials and in the service-life of coatings in electric thrusters. In particular, in this work we devote attention to the dynamics of an argon weakly ionized plasma in the presence of a collecting wall. It is proposed a kinetic model in a 1D1V planar phase-space geometry. The model accounts for the electric field coupled to the system by solving the associated Poisson’s equation. To solve numerically the resulting non-linear system of equations, the Propagator Integral Method is used in conjunction with a slabbing method. On each interrelating plasma slab the integral advancing scheme operates in velocity space, in such a way that the all the species dynamics dominating the system evolution are kinetically described.

Analysis of the Long-term Service Life of Coatings Based on Alkali-activated Matrices Exposed to Chemically Aggressive Environments

The paper deals with the possibility of using materials with an alkali-activated matrix for the secondary protection of reinforced concrete structures. Attention is primarily paid to the resistance of this type of coating to the effects of chemically aggressive environments. The long-term effect of selected types of aggressive environments on the coating based on alkali-activated substances was monitored using a set of physico-mechanical and physico-chemical tests. For comparison, a commercially produced epoxy coating with an increased resistance to the effects of chemically aggressive environments, as declared by its manufacturer, was subject to an analogous set of tests.