INNOVATIVE PAINT SYSTEMS IN SHIPBUILDING

Толық мәтін

Introduction
Corrosion is a serious problem for any vessel, and its consequences can be extremely devastating. Metal corrosion affects every component of the vessel. The hull is constantly exposed to seawater. Initially, barely noticeable spots of rust appear on the surface. Gradually, these spots grow, developing into deep gouges. In severe cases, corrosion can penetrate the metal, creating holes. This not only detracts from the vessel's appearance but also significantly reduces its seaworthiness. The piping system suffers equally. Rust buildup inside the pipes narrows the flow area. This leads to clogged pipelines, reduced pump efficiency, and possible pipe rupture under pressure. This can lead to accidents and leaks of various liquids. Corrosion damage is particularly dangerous for cargo tanks and fuel systems, where a leak can lead to serious environmental consequences. The destructive processes affect both welds and the entire metal structure. Welded areas are where metal is most vulnerable, and this is where corrosion often begins. This gradually leads to weakening of fasteners and the development of cracks. The economic consequences of corrosion are truly staggering. These include both direct losses from corrosion (metal oxidation) and indirect ones. As a result, the annual corrosion control budget for an average merchant vessel can reach several million dollars, not counting unforeseen expenses and lost revenue due to downtime. Most importantly, corrosion directly impacts vessel safety. Weakened structures may fail to withstand the load, which poses a risk of emergency situations. In severe cases, corrosion can render the vessel unfit for further operation, which means not only the loss of the vessel itself but also enormous financial losses for the owner [1].
In the modern shipbuilding industry, advanced technologies for protecting metal structures from corrosion are rapidly being introduced. Next-generation anti-corrosion systems are based on the use of nanostructured materials and composite coatings. The key to working with these materials is understanding how they will behave within the protective coating. Particular attention is given to microscopic analysis of materials, which allows for quantitative assessment of particle size, shape, and aggregation properties.
1. Types of nanofillers for corrosion resistance studies.
A scientific experiment was conducted to study the effect of various types of nanofillers on the corrosion resistance of paint coatings. The study involved PF-167 marine enamel modified with the following types of fillers:
- traditional chalk
- natural talc
- nanosized talc
- nanosized chalk
The study included a comparative study of the effectiveness of each filler type to assess their potential for enhancing the anticorrosive properties of paint and varnish materials.
Mineral fillers are a fundamental component determining the anticorrosive properties of modern paint and varnish compositions. This study focuses on nanosized carbonate fillers as promising modifiers for protective coatings.
Carbonate fillers, such as calcite (chalk) and dolomite, exhibit pronounced chemical activity against carboxyl-containing film-forming substances, particularly alkyd resins.

Talc fillers (magnesium silicate) are characterized by high chemical inertness and minimal structural porosity. This filler effectively inhibits diffusion processes and enhances the barrier properties of the coating.
The combined use of these fillers provides a synergistic effect in the formation of protective coatings with improved performance characteristics.

A study of the elemental composition of natural chalk yielded the following results: the main component of the material is calcium oxide (CaO), accounting for 95% of the total sample weight. The secondary component, magnesium oxide (MgO), was found at 5%.

Morphological analysis revealed a high degree of particle dispersion, with the crystalline modification of calcite predominating. The material has a uniform structure. A study of the elemental composition of talc revealed a structural organization of the material characterized by a pronounced coarse dispersion. The morphological characteristics are represented by needle-like and fibrous aggregates and flaky formations. The results of elemental analysis of the talc raw material demonstrated a predominant content of silica (SiO2) and magnesium oxide (MgO). The content of aluminum oxide Al2O3 and trivalent iron oxide (Fe2O3) is minimal.

2. Conducting an experimental study.
Carbon steel grade St3 was selected as the base material for the study. Standard PF-167 marine enamel and a modified paint and varnish composition with the addition of nanosized particles of chalk and talc were applied to the test samples.
Before applying the coatings, a preparatory stage of processing of the steel samples was carried out. This included mechanical surface treatment with an abrasive, removal of grease contaminants, and application of a primer coat.
The coating application process was carried out with a 48-hour intercoat curing period. The drying temperature was 20-20°C.
The following material samples were prepared for the experimental study:
Control group – steel sample coated with base enamel without additional modifiers.
Experimental group No. 1 – sample with a coating based on a traditional talc filler.
Experimental Group No. 2 – sample modified with nanosized talc particles.
Experimental Group No. 3 – sample with a coating containing a classic chalk filler.
Experimental Group No. 4 – sample modified with nanosized chalk particles.
Each sample represented a separate experimental model for studying the effect of different types of fillers on coating characteristics.
The experimental study was conducted using the potentiodynamic polarization method. A specialized three-electrode electrochemical system integrated with a measuring instrument, a P8S potentiostat, was used. The main element of the measuring cell consists of a hollow glass cylinder with a diameter of 3 centimeters. The test sample – a steel sample with a coating – is placed in the cylinder. The electrolyte medium was a 3% aqueous solution of sodium chloride (NaCl), providing the necessary conditions for electrochemical measurements.

Figure 1 – Potentiodynamic Polarization Method
1 – Control, 2 – Experimental Group No. 1 (EG), 3 – EG No. 2, 4 – EG No. 3, 5 – EG No. 4

For all samples, the potential scan rate was 10 millivolts per second. The measurement range spanned from -0.9 to +0.3 volts. The test method involved permanent immersion of the test samples in a sodium chloride solution (3%). [5].

Conclusion
The analysis of the experimental data obtained from the polarization curves convincingly demonstrates that paints and varnishes containing chalk and its nanoscale components provide a high level of protection against corrosion.

Interpretation of the experimental data (see Figure 1) allows us to draw conclusions regarding the corrosive activity of the samples. The base enamel (unmodified coating) exhibits the highest corrosion current values ​​among all tested samples. Talc modifications (both traditional and nanoscale forms) are characterized by reduced corrosion current levels, but an insufficient protective effect. Chalk compositions (including nanoscale modifications) demonstrate significant suppression of corrosion processes and a significant reduction in corrosion current values. Experimental groups Nos. 3-4 achieve a full level of protection, which is not recorded by measuring equipment.
Based on the obtained results, a ranked order of corrosion protection effectiveness for steel structures is constructed: control < talc < nanoscale talc < chalk ≈ nanoscale chalk.
A detailed analysis of PF-167 paint and varnish samples created with chalk and talc fillers revealed inclusions of iron oxide (FeO) in the structure of both types of enamel compositions. The presence of impurities indicates the occurrence of corrosion processes in both systems studied. However, despite this, the nature of the corrosion demonstrates a significant difference in the rate of damage between the samples.
The chalk enamel coating significantly slows down the corrosion process, while the concentration of iron oxide formed remains extremely low—only 0.4%.
The corrosion process on the steel surface with the talc enamel coating is significantly more intense, as evidenced by the significantly higher iron oxide content—0.99%.
A comparative analysis of the protective properties demonstrated the superiority of chalk enamel over talc enamel in terms of corrosion protection.

Авторлар туралы

Ekaterina Karzina

Saint Petersburg State Maritime Technical University

Хат алмасуға жауапты Автор.
Email: ekaterina.plaskeeva@list.ru
SPIN-код: 7638-3213

Cand. Sci. (Engineering), Associate Professor at the Department of Chemistry

Ресей, Saint Petersburg

Marina Gaidym

Saint Petersburg State Marine Technical University

Email: marina.zhdanova.1998@mail.ru
SPIN-код: 5395-5509

Assistant at the Department of Chemistry; Postgraduate Student

Ресей, Saint Petersburg

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