Electrochemical corrosion and materials properties of reactively sputtered TiN/TiAlN multilayer coatings

TiN/TiAlN multilayers of 2 μm thickness were successfully prepared by reactive DC magnetron sputtering method. XRD pattern showed the (1 1 1) preferential orientation for both TiN and TiAlN layers. XPS characterization showed the presence of different phases like TiN, TiO₂, TiON, AlN and Al₂O₃. Cross sectional TEM indicated the columnar growth of the coatings. The average RMS roughness value of 4.8 nm was observed from AFM analysis. TiN/TiAlN coating showed lower friction coefficient and lower wear rate than single layer coatings. The results of electrochemical experiments indicated that a TiN/TiAlN multilayer coating has superior corrosion resistance in 3.5% NaCl solution.     

Monitoring the degradation of a high solids epoxy coating by means of EIS and EN

This paper reports a study of the degradation processes suffered by steel samples painted with a high solid content epoxy coating. Because this coating shows a high resistance when exposed to NaCl solutions, HCl solutions were employed to accelerate the corrosion processes. Macroscopic images were used to observe the coating degradation. Then electrochemical techniques, electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) were employed to monitor the corrosion behaviour of the system studied. A close correlation was found between EIS and EN data. Several parameters were estimated using these techniques: R_po, R_ct, C_c, C_dl and Z_0.1 Hz using EIS, and R_n using EN. In addition, a new parameter estimated by means of EN was employed, Z_0.1 Hz(EN). The evolution of all these parameters with time enabled the effective monitoring of the degradation stage of the coating.     

Comprehensive study on corrosion protection properties of Al2O3, Cr2O3 and Al2O3–Cr2O3 ceramic coatings deposited by plasma spraying on carbon steel

In this study, individual Al₂O₃ and Cr₂O₃ coatings and Cr₂O₃-25, 50, 75 wt% Al₂O₃ composite coatings were applied on carbon steel by atmospheric plasma spraying method. Corrosion experiments were performed on as-sprayed and epoxy resin sealed coatings including potentiodynamic polarization, electrochemical impedance spectroscopy and long-term immersion in 3.5 wt% NaCl solution. Phase composition and microstructure of the coatings were investigated by x-ray diffraction, optical microscopy and scanning electron microscopy, before and after the corrosion experiment. The results showed that the Cr₂O₃ coating exhibited the best corrosion resistance, due to the densest microstructure and highest adhesion strength. The Cr₂O₃-25 wt% Al₂O₃ coating had the highest interconnected porosities and thus had the least corrosion resistance compared to other coatings. In general, the as-sprayed coatings induced a maximum increase of 3.93 times the polarization resistance (R_p) in the polarization experiment and a 3.5 times increase in the charge transfer resistance (R_ct) in the EIS experiment, which was not significant. Stresses caused by increased volume of corrosion products in the coating-substrate interface resulted in the spallation of Cr₂O₃-25, 50 wt% Al₂O₃ coatings from the substrate over long-term of immersion. The adhesion strength of the coatings was a determining criterion for the long-term durability of the coatings. The sealing treatment resulted in a significant increase in R_p and R_ct.     

Effect of WC on electrodeposition and corrosion behaviour of chromium coatings

To study the effect of WC particles on corrosion behaviour of chromium coating steel samples were plated in Cr(VI) baths with various concentrations of WC. XPS, EPM and XRD were used to study the chemical composition, morphology and texture of the coatings. The corrosion behaviour was studied at different exposure times in solution containing 0.01 mol L^–1 H₂SO₄ + 0.5 mol L^–1 Na₂SO₄ using cyclic voltammetry and impedance spectroscopy. Cyclic polarization measurements suggest that WC particles slow down the processes of passive film dissolution and penetration of aggressive ions to the substrate. Electrochemical impedance spectroscopy (EIS) was used to reveal the details of the corrosion process at the solution/electrode interface. The simulation of EIS data with a proposed equivalent circuit model made it possible to obtain quantitative valuation of the Y₀ (Q_c), Y₀ (Q_s) and R_pore parameters, reflecting corrosion behaviour of samples at the solution/electrode interface. Samples plated in a Cr(VI) bath with WC provided better resistance to corrosion than those plated in a bath without WC. Analysis of the data obtained suggests that WC particles enhance corrosion resistance due to the microstructural features of the coatings.     

Hydrophobic benzoxazine-cured epoxy coatings for corrosion protection

A hydrophobic benzoxazine-cured epoxy coating (EPB) was prepared by a dip coating and thermal curing method using benzoxazine monomer (B-TMOS) as curing agent. Fourier transform infrared (FTIR) analyses confirmed the presence of thermal curing reactions and hydrogen-bonding interactions in the epoxy/polybenzoxazine system. The hydrophobicity of epoxy coatings induced by the incorporation of B-TMOS was enhanced significantly, and the water contact angles of resultant EPB coatings were higher than 98°. The corrosion protection ability of epoxy coatings was investigated by open-circuit potentials, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) methods. The results showed that the charge transfer resistance (R_ct) of EPB coatings was increased by about three orders of magnitude compared with bare mild steel, and the protection efficiency values of all EPB samples were more than 98%. This increased corrosion protection property could be attributed to the high hydrophobic performance of EPB coatings.     

Application of a transmission line model to evaluate the influence of structural defects on the corrosion behavior of arc-PVD CrN coatings

The effect of bias voltages (40 V, 80 V, and 40/60/80 V) on microstructure and electrochemical properties of arc-PVD CrN coatings were evaluated. Increasing the bias voltage produced microstructural changes, from well-defined columns to columnar grains, and increased defect size. The electrochemical response proved susceptible to the defect type. Nano-droplets promoted the formation of oxides, while large pores allowed the migration of the electrolyte to the substrate/CrN interface. An impedance equivalent circuit based on the Bisquert transmission line was proposed to fit the experimentally obtained impedance spectra. The equivalent circuit allowed correlating the coating electrochemical response to the defect densities and sizes. Samples deposited with 40 V showed the lowest corrosion current (0.05 μA/cm² ± 0.01), which was supported by the highest resistances to the transport of ions through the pores (R_p = 1047 ± 88 kΩ?cm²). Films obtained with 80 V reduced R_p values by two magnitude orders compared to CrN 40 V. The increase of pore resistance in CrN 40 V was associated with the oxidation of nano-droplets (proposed auto-protection phenomenon), which blocks open pinholes due to the smallest average size of defects. Tailoring a gradual increase of the bias voltage (40/60/80 V) preserves the auto-protection mechanism of droplets and improves the surface finish of the coating.     

Growth,mechanical properties,and tribological performance of TiAlN/NbN and NbN/TiAlN bilayer coatings

Three different coatings, namely TiAlN, TiAlN (external)/NbN (internal) and NbN (external)/TiAlN (internal), were deposited on cemented carbides by arc ion plating. The comparative investigation conducted in this study elucidates the effect of the NbN layer and coating systems on the growth, mechanical properties, and tribological performance of the coatings. The results showed that the surface of the TiAlN and TiAlN/NbN coatings was smoother when TiAlN served as the external layer. The NbN/TiAlN coating, wherein NbN formed the external layer, had a much rougher but more symmetrical surface. With the introduction of the NbN layer, the increased micro stress induced a lower adhesion strength in the TiAlN/NbN and NbN/TiAlN coatings. The TiAlN/NbN and NbN/TiAlN coatings exhibited higher hardness and hardness/effective elastic modulus (H/E*). During the friction test, when the temperature was elevated to 700 °C, the tribological performance of the monolayer TiAlN coating was the lowest because of the TiO₂-induced breakage of the dense tribo-oxide film. The NbN layer participated in the formation of a NbO_x film at elevated temperatures, which was responsible for the high tribological performance of the two bilayer coatings. When the NbN layer was on the outermost layer and in direct contact with the elevated temperature atmosphere, the NbN/TiAlN coating generated a tribo-oxide film with high integrity, and its coefficient of friction decreased by 27% of that at room temperature. Therefore, the NbN/TiAlN coating exhibited the highest wear resistance at 700 °C.     

Corrosion resistance properties of electroless nickel composite coatings

Electroless nickel (EN) composite coatings incorporated with PTFE and/or SiC particles demonstrated significantly improved mechanical and tribological properties as well as low surface energy which are desired for anti-sticking and wear resistant applications. The corrosion resistance of these composite coatings, however, has not been systematically studied and compared. This work aimed to investigate the corrosion characteristics of EN composite coatings using electrochemical measurements which include open circuit potential (OCP), electrochemical impedance spectroscopy and potentiodynamic test. The effects of the co-deposited particles on corrosion behavior of the coatings in 1.0 N H₂SO₄ and 3% NaCl media were investigated. The surface autocatalytic properties and the post-heat-treatment on coating corrosion resistance were also discussed. The results showed that both EN and EN composite coatings demonstrated significant improvement of corrosion resistance in both acidic and salty atmosphere. Ni striking substantially enhanced the corrosion resistance due to the improvement of the surface autocatalytic properties and homogeneity. Proper post-heat-treatment significantly improves the coating density and structure, giving rise to enhanced corrosion resistance.     

Investigation of the tribological and biomechanical properties of CrAlTiN and CrN/NbN coatings on SST 304

This study examines the influence of thin layer coatings of CrAlTiN and CrN/NbN, deposited via physical vapor, on the biocompatibility, mechanical, tribological, and corrosion properties of stainless steel 304. The microstructure and morphology of the thin CrAlTiN and CrN/NbN layers were characterized by scanning electron microscopy (SEM), EDX, and X-ray diffraction. The pin on disc wear test was performed on bare and metal-nitride coated SST 304 under a 15 N load at 60 rpm and showed that the wear rates of the thin CrAlTiN and CrN/NbN film coatings were lower than the bare substrate wear ratio. The coefficients of friction (COFs) attained were 0.64, 0.5, and 0.55 for the bare substrate, CrN/NbN coating, and CrAlTiN coating, respectively. Nano indentation tests were also performed on CrAlTiN-coated and CrN/NbN-coated SST 304. The nanohardnesses and Young's moduli of the coated substrates were 28 GPa and 390 GPa (CrN/NbN-coated) and 33 GPa and 450 GPa (CrA1TiN-coated), respectively. For comparison, the nanohardness and Young's modulus of the uncoated substrate were 4.8 GPa and 185 GPa, respectively. Corrosion tests were conducted, and the behaviors of the bare and metal nitride-deposited substrates were studied in CaCl₂ for seven days. The corrosion Tafel test results showed that the metal-nitride coatings offer proper corrosion resistance and can protect the substrate against penetration of CaCl₂ electrolyte. The CrN/NbN-coated substrates showed better corrosion resistance compared to the CrAlTiN-coated ones. In evaluating the biocompatibility of the CrAlTiN and CrN/NbN coatings, the human cell line MDA-MB-231 was found to attach and proliferate well on the surfaces of the two coatings.     

Electrochemical impedance spectroscopy and corrosion behaviour of Al2O3-Ni nano composite coatings

In this paper, the results on the electrochemical impedance spectroscopy and corrosion properties of electrodeposited nanostructured Al₂O₃-Ni composite coatings are presented. The nanocomposite coatings were obtained by codeposition of alumina nanoparticles (13 nm) with nickel during plating process. The coating thickness was 50 μm on steel support and an average of nano Al₂O₃ particles inside of coatings at 15 vol.% was present. The structure of the coatings was investigated by scanning electron microscopy (SEM). It has been found that the codeposition of Al₂O₃ particles with nickel disturbs the nickel coating's regular surface structure. The electrochemical behavior of the coatings in the corrosive solutions was investigated by polarization potentiodynamic and electrochemical impedance spectroscopy methods. As electrochemical test solutions 0.5 M sodium chloride and 0.5 M potassium sulphate were used in a three electrode open cell. The corrosion potential is shifted to more negative values for nanostructured coatings in 0.5 M sodium chloride. The polarization resistance in 0.5 M sodium chloride decreases in 24 h, but after that increases slowly. In 0.5 M potassium sulphate solution the polarization resistance decreases after 2 h and after 30 h of immersion the polarization resistance is higher than that of the beginning value. The corrosion rate calculated by polarization potentiodynamic curves obtained after 30 min from immersion in solution is smaller for nanostructured coatings in 0.5 M potassium sulphate (4.74 μm/year) and a little bit bigger in 0.5 M sodium chloride (5.03 μm/year).     

Protective abilities of nanocomposite coatings containing Al2O3 nano-particles loaded by CeCl3

The protective ability of hybrid nano-composite oxysilane coatings, deposited via sol–gel method on AA2024-T3 – aluminium alloy, were studied by linear voltammetry (LVA) and electrochemical impedance spectroscopy (EIS) methods in 0.05 M solution of NaCl. Cerium chloride (CeCl₃) was incorporated as an inhibitor into a sol–gel hybrid matrix in two different routes: directly and via filled porous Al₂O₃ nano-particle aggregates with diameters up to 500 nm. The influences of the inhibitor concentration, as well as the influence of nano-particles on the barrier properties and the susceptibility against corrosion, were evaluated and EIS spectra were fitted by appropriated equivalent circuits. The values for C_coat, R_coat, C_oxy and R_oxy were achieved and their evolution over time was investigated. The investigated coatings possess highly expressed barrier properties (10⁶ to 10⁷ Ω cm²). Despite of the chloride ions inside of the matrix, some samples illustrated a significant durability of over 4000 h during exposure to the corrosion medium before first signs of corrosion appeared. The electrochemical results were compared with the neutral salt spray test. Thus, it was proved that the potential of these coatings is to be used as anticorrosive protective materials and are candidate to replace Cr(VI)-based anti-corrosion coatings.     

A study of microstructural and electrochemical properties of ultra-thin DLC coatings on altic substrates deposited using the ion beam technique

Microstructural and electrochemical characterization of diamond like carbon (DLC) ion beam-deposited on AlTiC (70 wt% Al₂O₃+30 wt% TiC) substrate has been carried out. Tapping mode atomic force microscopy (AFM) imaging showed that the island-like topography of DLC-coated substrates is similar to the un-coated one, indicating the uniform coverage of DLC without visible pinholes. Confocal micro-Raman analysis demonstrated that the total Raman intensity, as well as the I_D/I_G ratio, increases with the coating thickness. Electrochemical impedance spectra showed that with the increasing DLC coating thickness, a transition from one-time constant response to two-time constant response occurred when the coating thickness equals 5 nm (IS2), indicating the existence of micro-defects in the coatings which are invisible for AFM. More detailed analysis using the equivalent circuit model revealed that the charge transfer resistance (R_ct) at electrolyte/substrate interface and the resistance (R_p) related to DLC coatings increase significantly with the coating thickness, while the double-layer capacitance (C_dl) and the capacitance (C_co) of DLC coatings decrease dramatically. All these phenomena can be interpreted in terms of the evolution of the subsurface diamond-like phase (sp³-bond) and the reduction of micro-defects in the DLC coatings with the growing film. As a result, an increase in the corrosion potential (E_c) with the DLC coating thickness was also detected using the Tafel technique. In consequence, the DLC coatings can improve significantly the anti-corrosion properties of AlTiC substrates when the coating thickness is more than a few tens of nanometres.     

Modification of Cr/CrN composite structure by Fe addition and its effect on decorative performance and corrosion resistance

A CrN ceramic coating is a promising substitution for electroplated Cr (Ⅵ) hard coatings; however, it has not yet replaced a decorative Cr (Ⅵ) layer owing to its low reflectivity of visible light and relatively poor corrosion resistance. A Cr/CrN composite structure can address these shortcomings. Our recent work demonstrated that an addition of Fe can facilitate the densification of hot-pressed Cr sputtering targets and enhance the mechanical properties of Cr/CrN composite coatings. In this work, we focus on reporting optical properties and corrosion resistance of the Fe-modified Cr/CrN layers for decorative applications, and clarifying the effect of Fe on these performances. The results show that Fe can increase the amount of metallic phase in the Cr/CrN composite structure and helps enhance its reflectance in the visible region. The composite coating deposited by Cr₉₀Fe₁₀ (at.%) target/alloy exhibits a greater reflectivity of visible light and a better corrosion resistance than those of a single-phase CrN coating. This is attributed to its fine microstructure, which is beneficial for a dense and smooth surface. The color of the coating can be controlled by both the partial pressure ratio of N₂ during deposition and the Fe content in the Cr-Fe sputtering target. The present results show that the addition of Fe can lead to the reduction in the processing cost of Cr targets, enhance the mechanical properties of the composite coatings, and broaden the deposition window. Such cost-effective Fe-modified Cr/CrN composite coatings are expected to be used in various decorative applications.     

Mechanism of corrosion protection of aluminum alloy substrate by hybrid polymer nanocomposite coatings

The corrosion protection of polymer clay nanocomposite, PCN coatings consisting of polyurea, siloxanes, epoxy ester and montmorillonite clay was determined. Corrosion resistance of the coating, was assessed by monitoring the polarization resistance and impedance of coated aluminum alloy, Al 2024-T3, coupons immersed in 3.5 wt.% of sodium chloride, NaCl, solution. Direct current polarization and electrochemical impedance spectroscopic techniques were used to measure polarization resistance and impedance of the samples, respectively. Diffusion of saturated salt solution into free-standing PCN films was measured gravimetrically and diffusivity of the nanocomposites was determined. The presence of clay decreases diffusivity and increases corrosion resistance of the non-scribed coatings containing up to 10 wt.% of clay. A correlation between polarization resistance and diffusivity was made. It was shown that for non-scribed coatings, polarization resistance increases with decreasing diffusivity. A relationship between coating's diffusivity and weight fraction of clay was established. Increasing clay concentration also resulted in decreasing diffusivity. The scribed nanocomposite coatings show slightly decreasing polarization resistance with increasing weight fraction, however, the polarization resistance of scribed coatings containing low clay weight fraction in the range between 0.5 and 2.0 wt.% was higher than that for the matrix. A barrier mechanism of corrosion prevention of the coated substrate is proposed for non-scribed coatings. The viscoelastic property of the nanocomposites was determined by using dynamic mechanical spectrometer. A correlation between polarization resistance of the coatings and the rubbery plateau modulus on the one hand and polarization resistance and tan δ peak area for α-transition of the nanocomposites is made. Decreasing tan δ peak area for α-transition and increasing rubbery plateau modulus resulted in increasing coatings polarization resistance.     

Comparison of single and multilayer coatings based on ormosil and conversion layers for aluminum alloy corrosion inhibition

Corrosion resistance behavior of single and multilayer coatings based on ormosil, trivalent chromium conversion coating (tccc) and hexavalent chromium conversion coatings (hccc) on the surface of 2024-T3 aluminum alloy (AA) was investigated using potentiodynamic polarization curves and accelerated salt spray testing. The magnitude of the corrosion resistance for single layer coatings increased tccc < ormosil < hccc. Multilayer ormosil/ormosil coatings are subject to phase separation, leading to poor performance in the electrochemical and accelerated salt spray testing. The presence of either hccc or tccc in the multilayer film was found to augment the inherent corrosion resistance of the ormosil barrier film. Multilayer coatings composed of either tccc/ormosil or hccc/ormosil were found to exhibit R_corr values in the range 158–177 kΘcm². This implies that the environmentally-benign and nontoxic trivalent chromium conversion coating used in combination with an ormosil film may be a potential alternative for hexavalent chromium conversion coatings. Environmental Institute, 003, Life Science East, Stillwater, OK 74078.     

Enhancement of the Ti-6Al-4V alloy corrosion resistance by applying CrN/CrAlN multilayer coating via Arc-PVD method

In this study, the Ti-6Al-4V substrate was coated by CrN-CrN/TiN-TiN and CrN/CrAlN multilayer coatings using the cathodic arc physical vapor deposition (Arc-PVD) method. The results of potentiodynamic polarization (PDP) have shown the lowest and highest corrosion current density belong to the double-layer (0.16 µA/Cm²) and TiN (0.51 µA/Cm²) samples, indicating the higher corrosion resistance of the double-layer coating. The field emission electron microscope (FESEM), X-ray diffraction pattern (XRD), open circuit potential (OCP), PDP, and electrochemical impedance spectroscopy (EIS) analysis were employed in order to characterize the coatings and evaluate their corrosion behavior. Finally, applying the double-layer coating resulted in the significant improvement of the protective behavior of the Ti-6Al-4V alloy, as compared to the sample coated with TiN in corrosive environments.     

Comparison of electrochemical behavior of CrN single-layer coating and Cr/CrN nanolayered coating produced by cathodic arc evaporation physical vapor deposition

The aim of the present work is to study the CrN single-layer coating and the Cr/CrN nanolayered coating by cathodic arc evaporation physical vapor deposition (CAE-PVD) on AISI 304 stainless steel and to assess the electrochemical behavior of the coatings. Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) were utilized to study the morphology and microstructure of the coatings. The mechanical behavior of the coatings was studied by the nanoindentation technique. The electrochemical behavior of the formed coatings in 3.5 wt.% NaCl solution was investigated via electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) tests. Based on the microscopic images, it was realized that both CrN and Cr/CrN coatings were formed having a dense structure on the substrate. The results of EIS measurements showed gradual changes in the polarization resistance of the Cr/CrN nanolayered coating during the immersion time. However, significant changes in the polarization resistance of the CrN single-layer coating were seen by increasing immersion time comparing with the Cr/CrN coating. The higher polarization resistance of the Cr/CrN coating can be attributed to the effects of the interface between the layers in comparison to the CrN coating.     

Enhancement of Corrosion Performance of Epoxy Coatings by Chemical Modification With GPTMS Silane Monomer

In this paper, commercial epoxy resin was chemically modified by different amounts of 3-glycidoxypropyltrimethoxysilane (GPTMS) monomer using an organotin compound as catalyst, aiming to improve the anti-corrosion performance of epoxy coatings on 2024-T3 aluminum alloy substrate. Electrochemical impedance spectroscopy (EIS) was used to evaluate the barrier properties against water permeation and protectiveness of silane-modified epoxy coatings. The results showed that all the modified coatings presented higher barrier performance and better corrosion performance than pure epoxy coating, which were characterized by higher charge transfer resistance (R _ct) and lower double-layer capacitance (C _dl) at the electrolyte/metal interface. The improvements in corrosion performance and wet adhesion of modified epoxy coatings were also observed by the Machu test and boiling water test, respectively. Interestingly, it was found that the glass-transition temperature (T _g) of silane-modified epoxy coatings decreased only slightly during immersion in 3.5 wt% NaCl solution, in contrast with pure epoxy coating, which was observed to decrease significantly after water permeation. The corrosion performance of epoxy coatings was, thus, improved when the amount of chemically grafted silane monomer increased in the content range investigated in the present work.     

Investigation of high temperature wear resistance of TiCrAlCN/TiAlN multilayer coatings over M2 steel

In this study, TiCrAlCN/TiAlN multilayer coatings were deposited on M2 high speed steel substrates by the Closed-Field Unbalanced Magnetron Sputtering system. The chemical composition, microstructure, morphology, mechanical and high temperature wear resistance properties of the coatings were characterized, analyzed and compared to the substrate. The high temperature wear tests were carried out under a load of 2 N at the lap (wear test distance) of 50 m and in dry sliding condition at Room Temperature (RT), 150, 300, 450, and 600 °C on atmospheric conditions. It has been found that the TiCrAlCN/TiAlN multilayer coatings have a higher wear resistance than the M2 substrate. The stable friction behavior and low friction tendency was determined at 600 °C. When the test temperature increased, the wear rates decreased. Narrow and smooth wear tracks and also the lowest wear rate were obtained at 600 °C.     

The application of polycarbazole,polycarbazole/nanoclay and polycarbazole/Zn-nanoparticles as a corrosion inhibition for SS304 in saltwater

Polycarbazole (PCz), polycarbazole/nanoclay and polycarbazole/Zn-nanocomposites were chemically and electrochemically synthesized on a stainless steel (SS304) electrode. The modified electrodes were characterized by electrochemical methods (CV and chronoamperometry), Fourier transform infrared spectroscopy (FTIR)-attenuated transmission reflectance (ATR), scanning electron microscopy (SEM)-energy dispersive X-ray analysis (EDX), four point probe, electrochemical impedance spectroscopy (EIS), and equivalent circuit model of R_s(Q_c(R_c(Q_pR_ct))). The electrochemical behavior of the modified films on SS304 was assessed by open circuit potential monitoring, potentiodynamic polarization and EIS measurements to test the corrosion protection efficiency against 3.5% NaCl solution. PCz, PCz/nanoclay and PCz/nanoZn films obtained by chemical method coated on SS304 electrode exhibited better corrosion protection performance compared to the films obtained by the electrochemical method. This result may be attributed to the effective formation of a thin and protective layer. The highest protection efficiency (PE = 99.81%) was obtained for chemically synthesized PCz films.