Plasma Coating Research Articles

IMPROVING THE EFFICIENCY OF RESTORATION AND HARDENING OF THE WORKING BODIES OF TILLAGE MACHINES BY PLASMA-POWDER SURFACING OF CARBIDE ELECTROEROSIVE MATERIALS

The use of powders obtained from solid alloy waste as a highly solid dispersed component of the composition for plasma-powder surfacing will improve the quality, reliability and durability of plasma coatings of working bodies of tillage machines with a minimum of costs for powder materials. However, the properties of these plasma coatings have not been studied enough, so it is necessary to conduct comprehensive studies. (Research purpose) The research purpose is improving the technology of restoration and hardening of the working bodies of tillage machines by plasma-powder surfacing of powder materials obtained by electroerosive dispersion of solid alloy waste T30K4. (Materials and methods) Carbide powders made by electrodispersing solid alloy waste T30K4 in kerosene were used to obtain plasma coatings. We chose for the renovation object a pointed cultivator paw made of 40XC rolled steel. The obtained plasma coatings were studied using modern equipment and complementary methods of physical materials science. (Results and discussion) We have developed, tested and investigated a new technology for restoring and strengthening the working bodies of tillage machines using the example of a pointed cultivator paw by plasma-powder surfacing of carbide electroerosive powder materials. The effectiveness of the development was confirmed by the properties of plasma coatings: the microstructure of the coating has a fine-grained structure, without inclusions, uniform phase distribution and the absence of pores, cracks and discontinuities; elements W, Ti and Co in the coating are evenly distributed; phases of carbides WC and TiC are present; the grain size of the coatings is about 0.3 micrometers; the microhardness of the coatings is about 14245 megapascals. (Conclusions) The results of field tests showed that the resource of the working bodies of tillage machines, restored and strengthened with carbide electroerosion materials, is 1.25 times higher than the resource of new parts.

In vitro biological responses of plasma nanocoatings for coronary stent applications.

In-stent restenosis and thrombosis remain to be long-term challenges in coronary stenting procedures. The objective of this study was to evaluate the in vitro biological responses of trimethylsilane (TMS) plasma nanocoatings modified with NH3 /O2 (2:1 molar ratio) plasma post-treatment (TMS + NH3 /O2 nanocoatings) on cobalt chromium (CoCr) alloy L605 coupons, L605 stents, and 316L stainless steel (SS) stents. Surface properties of the plasma nanocoatings with up to 2-year aging time were characterized by wettability assessment and x-ray photoelectron spectroscopy (XPS). It was found that TMS + NH3 /O2 nanocoatings had a surface composition of 41.21 ± 1.06 at% oxygen, 31.90 ± 1.08 at% silicon, and 24.12 ± 1.7 at% carbon, and very small but essential amount of 2.77 ± 0.18 at% nitrogen. Surface chemical stability of the plasma coatings was noted with persistent O/Si atomic ratio of 1.292-1.413 and N/Si atomic ratio of ~0.087 through 2 years. The in vitro biological responses of plasma nanocoatings were studied by evaluating the cell proliferation and migration of porcine coronary artery endothelial cells (PCAECs) and smooth muscle cells (PCASMCs). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay results revealed that, after 7-day incubation, TMS + NH3 /O2 nanocoatings maintained a similar level of PCAEC proliferation while showing a decrease in the viability of PCASMCs by 73 ± 19% as compared with uncoated L605 surfaces. Cell co-culture of PCAECs and PCASMCs results showed that, the cell ratio of PCAEC/PCASMC on TMS + NH3 /O2 nanocoating surfaces was 1.5-fold higher than that on uncoated L605 surfaces, indicating enhanced selectivity for promoting PCAEC growth. Migration test showed comparable PCAEC migration distance for uncoated L605 and TMS + NH3 /O2 nanocoatings. In contrast, PCASMC migration distance was reduced nearly 8.5-fold on TMS + NH3 /O2 nanocoating surfaces as compared to the uncoated L605 surfaces. Platelet adhesion test using porcine whole blood showed lower adhered platelets distribution (by 70 ± 16%), reduced clotting attachment (by 54 ± 12%), and less platelet activation on TMS + NH3 /O2 nanocoating surfaces as compared with the uncoated L605 controls. It was further found that, under shear stress conditions of simulated blood flow, TMS + NH3 /O2 nanocoating significantly inhibited platelet adhesion compared to the uncoated 316L SS stents and TMS nanocoated 316L SS stents. These results indicate that TMS + NH3 /O2 nanocoatings are very promising in preventing both restenosis and thrombosis for coronary stent applications.

Features of Plasma Coating Formation from Silicon Carbide on Titanium Alloy VT6

Features of Plasma Coating Formation from Silicon Carbide on Titanium Alloy VT6

Development of research and prediction of wear of plasma coatings from nickel-clad graphite powder

Development of research and prediction of wear of plasma coatings from nickel-clad graphite powder

Aspects of Creating Multilayer Coatings by Plasma Spraying

In the work, taking into account the state of the issue in the field of applying multilayer heat-shielding and wear-resistant coatings, directions of research are substantiated. The objectives of the development are: improvement of powder materials containing zirconium dioxide partially stabilized with yttrium oxide for plasma deposition of heat-shielding coa-tings; improvement of powder materials containing oxide ceramics and nickel-based alloys for plasma deposition of wear-resistant coatings; development of technological parameters of plasma spraying and subsequent processing by the effects of compression plasma on the coating; analysis of the quality of protective coatings obtained using the optimal technology by studying their structure and physical and mechanical properties. The ZrO 2 – 7 % Y 2 O 3 particles contain the predominant tetragonal Y 0.15 Zr 0.85 O 0.93 phase, monoclinic and cubic ZrO 2 phases, and the Al 2 O 3 –TiO 2 –Ni–Cr–Al–Y–Ta composition contains the Cr 1.12 Ni 2.88 phase of the nickel-based solid solution, the a-Al 2 O 3 , g-Al 2 O 3 phases, and the orthorhombic phase of titanium oxide TiO 2 that contribute to its wear resistance. subsequent optimization of technological parameters for the process of plasma spraying of multilayer heat-shielding and wear-resistant coatings. Technological parameters for the process of plasma spraying of multi-layer heat-shielding and wear-resistant coatings are investigated with subsequent optimization. The optimization criteria were the utilization factor of the sprayed powder material and the structure of the coatings. The influence of the spraying distance on the values of operational characteristics of the formed plasma coatings on Al 2 O 3 –TiO 2 –Ni–Cr–Al–Y–Ta has been studied. The obtained results of controlling the phase composition of coatings by varying the chemical composition of powder materials are presented. In the process of deposition, the differences in the phase composition of the formed material are the more significant, the more inhomogeneous the distribution of elements in the initial powder material. Tests have been carried out for cyclic testing in an oven at a maximum temperature within 1300 °C of heat-shielding coatings to determine their heat resistance. They proved the influence of the phase composition of the formed coatings on their ability to withstand high-temperature oxidation.

Validation of a whole exome/whole transcriptome liquid biopsy assay with correction for clonal hematopoiesis.

e15049 Background: Liquid biopsies have become integral to the management of patients with advanced malignancies, however significant deficiencies exist in currently used platforms. Liquid biopsy data often show unacceptably high discordance compared to gold standard tissue-based data; this is often due to false positives (FP) resulting from clonal hematopoiesis (CH) or increased false negatives due to inherently poor sensitivity as well as the confounding intra-patient or tumor stage dependent ‘non-shedder’ problem. Caris Assure is a novel whole exome (WES) and whole transcriptome (WTS) NGS assay performed on plasma and buffy coat (BC) fractions of whole blood that maximizes the number of unique nucleic acids, thereby increasing sensitivity as well as identifying incidental germline variants and correcting for CH. Methods: Matched tissue and whole blood specimens were obtained from 184 patients with solid tumors. Whole blood was collected in PAXgene ccfDNA tubes. DNA & RNA were co-extracted from matched plasma, BC, and FFPE tumor tissue specimens and prepared for NGS using hybrid bait capture methodology. Plasma and BC samples were tested using the Caris Assure WES/WTS assay as well as orthogonal assays. Tissue specimens were tested using Caris’ validated WES/WTS tissue assay. Results were compared between the plasma assays and matched tissues as well as using a majority-rules calling model. A positive plasma assay variant was counted a true positive if it was also identified in the matched tissue or the orthogonal plasma result. Similarly, a negative result was considered a true negative if either of the other two test results were also negative. Results: When data were analyzed from patients with metastatic disease and were focused on only those genes included in the limited orthogonal liquid panel, and tissue was treated as the gold standard, Caris Assure achieved a PPA for SNVs and INDELS of 81.4% and PPV of 85.1%, while the orthogonal assay achieved a PPA and PPV of 79.1% and 53.1%. When the majority rules approach was used, Assure PPA and PPV were 93.3% and 93.3%, respectively, compared to 91.1% and 64.1%. Germline variants detected by Caris Assure had 100% PPA & PPV when compared to the external germline assay. There were 444 pathogenic/likely pathogenic mutations detected across all assays. Of those, 77 (17.3%) were derived from CH and identified as such in the Caris Assure results, though they are inaccurately reported as tumor-derived variants using the comparator assay. Using Caris Assure corrected for CH-derived false positives, the correlation between plasma and tissue TMB was very strong (r = 0.9) when tissue and blood specimens were collected within 4 weeks of each other. Conclusions: The novel Caris Assure liquid biopsy platform demonstrates high sensitivity and specificity for somatic variants, while mitigating against FPs from CH, and identifying incidental germline pathogenic alterations.

CLIMATE: Assessing the clinical utility of miR-371a-3p as a marker of residual disease in stage 1 testicular germ cell tumour (TGCT) following orchiectomy: ANZUP 1906.

TPS5100 Background: There is impetus to identify biomarkers in TGCT to help select those at high-risk of relapse following orchiectomy and target interventions to prevent over-treatment. miR-371 has been shown to reliably predict presence of active malignancy with higher accuracy than currently available biomarkers. More clinical evidence is required to ascertain its clinical utility as a marker of microscopic disease to guide treatment recommendations in stage 1 TGCT and other settings. Methods: CLIMATE ANZUP1906 (ACTRN12622000247774) is a prospective, single-arm, non-interventional cohort study recruiting adults with clinical stage 1 TGCT entering active surveillance. Eligible participants are recruited within six weeks of orchiectomy and are willing to undergo active surveillance in accordance with the Australian and New Zealand Urogenital and Prostate (ANZUP) Cancer Trials Group Surveillance Recommendations (or similar), without adjuvant treatment. Participants with metastases, non-testicular primaries, or history of contralateral TGCT are ineligible. Serum, plasma, and buffy coat samples are collected at consent and every three months until 24 months (and at relapse, if applicable). miR-371 will be assessed using established protocols. Clinical data, including treatment(s), surveillance, and relapses are captured in Australia’s national TGCT registry, iTestis. Archival tissue from diagnosis ± relapse is identified for future translational research. The primary endpoint for CLIMATE is 12-month relapse-free survival of miR-371 positive/negative groups. Key secondary endpoints include miR-371 during surveillance and at relapse, concordance between serum/plasma miR-371 and archival tissue, and health economic analyses. Prior studies suggest ~20% of post-orchidectomy miR-371 samples are positive. A sample size of 200 participants will result in 20 relapses, 160 non-relapses and 20 individuals lost to follow-up, and will permit description of the primary endpoint. Patient-level data from CLIMATE will contribute to a joint analysis of parallel trials evaluating miR-371 in this setting, COG AGCT1531 and SWOG1823. The first participant was recruited to CLIMATE in February 2022. 9/12 study sites in Australia and New Zealand have been activated and 47/200 (24%) have been enrolled. Recruitment is expected to take 36 months, followed by a further 24 months follow-up. Clinical trial information: ACTRN12622000247774 .

Investigation of High-Temperature Erosion Behavior of NiCrAlY/TiO2 Plasma Coatings on Titanium Substrate

Investigation of High-Temperature Erosion Behavior of NiCrAlY/TiO2 Plasma Coatings on Titanium Substrate

Liquation Cracking in Row 3 Twin Turbine Vane Segment Caused by Malfunctioning Plasma Coating Gun

Abstract Transverse through-wall airfoil cracking was found in a row 3 twin turbine vane segment of a type used in heavy-duty gas turbine engines for power generation. A laboratory investigation determined liquation cracking (LC), a hot cracking mechanism, as the metallurgical cause of failure. As became apparent only after the investigation, the root cause of failure was a malfunctioning plasma gun used for thermal spraying the thermal barrier ceramic top coat onto the subject part.

Legacy and emerging per- and polyfluoroalkyl substances suppress the neutrophil respiratory burst

Per- and polyfluoroalkyl substances (PFASs) are used in a multitude of processes and products, including nonstick coatings, food wrappers, and fire-fighting foams. These chemicals are environmentally-persistent, ubiquitous, and can be detected in the serum of 98% of Americans. Despite evidence that PFASs alter adaptive immunity, few studies have investigated their effects on innate immunity. The report here presents results of studies that investigated the impact of nine environmentally-relevant PFASs [e.g. perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid potassium salt (PFOS-K), perfluorononanoic acid (PFNA), perfluorohexanoic acid (PFHxA), perfluorohexane sulfonic acid (PFHxS), perfluorobutane sulfonic acid (PFBS), ammonium perfluoro(2-methyl-3-oxahexanoate) (GenX), 7H-perfluoro-4-methyl-3,6-dioxa-octane sulfonic acid (Nafion byproduct 2), and perfluoromethoxyacetic acid sodium salt (PFMOAA-Na)] on one component of the innate immune response, the neutrophil respiratory burst. The respiratory burst is a key innate immune process by which microbicidal reactive oxygen species (ROS) are rapidly induced by neutrophils in response to pathogens; defects in the respiratory burst can increase susceptibility to infection. The study here utilized larval zebrafish, a human neutrophil-like cell line, and primary human neutrophils to ascertain whether PFAS exposure inhibits ROS production in the respiratory burst. It was observed that exposure to PFHxA and GenX suppresses the respiratory burst in zebrafish larvae and a human neutrophil-like cell line. GenX also suppressed the respiratory burst in primary human neutrophils. This report is the first to demonstrate that these PFASs suppress neutrophil function and support the utility of employing zebrafish larvae and a human cell line as screening tools to identify chemicals that may suppress human immune function.

MODEL FOR EVALUATING THE PLASMA COATING METHOD

The article considers the main prospects for the use of the method of coating plasma spraying. The essence of plasma spraying is disclosed, and the main advantages and disadvantages of this coating formation method are indicated. The method is characterized by high productivity and the possibility of forming high-quality coatings on machine parts for various functional purposes. It was found that the low stability of the spraying process, the structural complexity of the plasmatron and the need for mathematical modeling are constraining factors in designing new technological processes of plasma spraying. The possibility of further increasing the efficiency of plasma spraying by developing methods and means of automation and computerization of the spraying process is substantiated. Obtaining the required physical and mechanical properties of coatings applied to worn working surfaces of machine parts by plasma spraying is achieved by using modern electronic computing machines in the development of technological application processes. Based on the research a mathematical model for evaluating the method of plasma coating deposition was obtained. It allows the choice of applied materials and technological processes, as well as modeling options of design and technology solutions that meet the optimization condition. The data obtained from the results of studies allow evaluation of the impact of technological modes of coating formation on the optimization parameter.

Investigation of the Effect of NiCrAlY/Cr2O3/YSZ Plasma Coatings on Erosion Performance of MDN 420 Steel at High Temperature

Investigation of the Effect of NiCrAlY/Cr2O3/YSZ Plasma Coatings on Erosion Performance of MDN 420 Steel at High Temperature

Jonsko azotiranje i površinsko legiranje alata za rezanje tvrde legure H13A

Ion-plasma coatings are widely used to increase the wear resistance of hard alloy metalworking tools. However, plasma coatings are practically not combined with other technological operations and do not improve the physical and mechanical properties of tool working elements. Hardening tools made of hard alloys is one of the promising directions that is created by layered structures on the surface. It provides a gradient distribution of physical and chemical properties between the wear-resistant coating and the base material.

Исследование содержания кислорода и азота в плазменных покрытиях

A study was carried out on the content of oxygen and nitrogen in plasma coatings deposited from Co powder and its alloys (wt. %) Co – 32 Ni – 21 Cr – 8 Al – 0.5 Y, Co – 27.9 Cr – 7.04 Al – 3.25 Si – 2 Y. To do this, we used a conical nozzle attached to the plasma torch, which performs the extraction of the plasma flow after heating and accelerating the sprayed particles. As the power of the plasma jet increases, the content of oxygen and nitrogen in the Co coating increases. When alloying cobalt alloys with Cr, Al, Si, and Y, the oxygen content in the coatings increases less rapidly with increasing plasma jet power, but the nitrogen content in these coatings is higher than in the Co coating due to the interaction of alloying elements with nitrogen. The results for Co-based coatings were analyzed along with their previous data for coatings sprayed from powders based on Fe and Ni. Coatings based on Fe, Co, Ni were divided into four groups according to the mechanism of their interaction with oxygen. The first group includes pure metals, the second includes alloys alloyed with Cr, the third is additionally alloyed with Al, the fourth is alloys with complex alloying of Cr, Mn, C, B, Si with elements that actively interact with oxygen, including the formation of gaseous oxides. Doping with Cr reduces the oxygen content in coatings by 35 – 46 %, additional alloying with Al reduces the oxygen content in the coating by 57 – 78 %, doping with Cr, C, B, Si reduces the oxygen content in the coating by 92 – 95 %. We performed a detailed analysis of the nozzles used for the plasma torch.

Analysis of nickel-clad ceramic powder materials

The task of developing new powder materials for use in gas-thermal technologies is solved by cladding metal oxide particles with a refractory metal component. The results of studies of powders of domestic production based on aluminum oxide (corundum) and zirconium dioxide subjected to chemical nickel cladding (8 and 30 %) are presented. The morphology, granular and phase compositions, as well as the distribution of the elemental composition were studied using electron microscopy and X-ray diffraction analysis. It is shown that the formation of a dense and homogeneous metal shell around the particles of the matrix material occurs when 30 % of the metal is clad. According to X-ray diffraction analysis, powder materials have a multiphase composition: (Ni + α-Al2O3 + γ-Al2O3 + γ*-Al2O3) − for aluminum oxide powder clad with 8 % Ni; (Ni + α-Al2O3 + γ-Al2O3) - for aluminum oxide powder clad with 30 % Ni, (Ni + T-ZrO2) - for dioxide powder zirconium clad with 30 % nickel. New powder materials of domestic production are competitive in relation to foreign analogues and due to cladding with a metal component will contribute to improving the plasticity of plasma coatings formed from them.

Efficiency of the Action of Plasma Flows on the Surface of 30KhGSA Steel during the Deposition of Electric Arc Vacuum Ion–Plasma Coatings

Efficiency of the Action of Plasma Flows on the Surface of 30KhGSA Steel during the Deposition of Electric Arc Vacuum Ion–Plasma Coatings

Исследование содержания кислорода и азота в плазменных покрытиях на основе никеля

Studies were carried out on the oxygen and nitrogen content of nickel-based powders and plasma coatings therefrom. The Ni-based sprayed materials were divided into four groups according to the mechanism of their interaction with oxygen. The first group includes Ni, the second alloys alloyed with Cr, the third additionally alloyed with Al, the fourth alloys having more complex alloying with Cr, C, B, Si elements that actively interact with oxygen, including with the formation of gaseous oxides. Alloying 20 % Cr reduces the oxygen content of the coating by 35 %, alloying 17 % Cr – 10 % Al reduces the oxygen content of the coating by 57 %, more complex alloying 13.5 % Cr – 2.7 % Si – 1.65 % B – 0.36 % C — reduces the oxygen content of the coating by 92 %. Increasing the plasma jet power increases the oxygen content of the Ni20Cr coating from 0.55 to 1.6 %. Increasing the plasma jet power and preheating the substrate prior to sputtering results in a limited increase in the oxygen content of Ni – 17 % Cr – 10 % Al – 1 % Y and Ni – 15 % – Cr 4 % – Fe 0.8 % C – 4.1 % Si — 3.1% B coatings using a plasma nozzle to eliminate the thermal effects of the plasma jet. The Ni – 17 % Cr – 10 % Al – 1 % Y coating sprayed with the nozzle contains 0.48 % O and 0.14 % N instead of 2.31 % O and 0.37 % N when sprayed without the nozzle. An increase in the oxygen and nitrogen content in the coatings Ni, Ni – 20 Cr and Ni – 40 Cr together with the formation of a liquid-hardened structure in these coatings determines an increase in microhardness relative to the value for the powder by 1.6 – 1.9 times.

Структурные изменения плазменных покрытий гидроксиапатита в зависимости от мощности плазмы

The structure of hydroxyapatite (HA) plasma coatings obtained by changing the power of the plasma torch (P) from 20 to 26 kW was studied by X-ray diffraction analysis. All coatings contained the decomposition products of hydroxyapatite in the plasma flow, phases of tetracalcium phosphate (TTCP) and CaO. Their number, which increases with increasing P and plasma temperature (Tp), is determined by the partial loss of phosphorus by the initial HA powder in plasma and the shift in the chemical composition of the coating to higher calcium contents. An increase in P and Tp is accompanied by an increase in the intensity of the HA basic texture. In the range of 24 < P < 26 kW, the intensity ratio of X-ray reflections HA δ = I(200)/I(211) exceeds 3.0 in its value, while at P = 20 kW δ <1.5. The presence of orientation relationships between the predominant crystallographic orientations of HA and TTCP crystals in coatings is associated with the similarity of their structures, the proximity of lattice periods, and the presence of identical fragments in their structures. The possibility of the formation of mixed-layer structures involving these compounds is discussed. The following factors are considered as the factors that have the greatest influence on the nature of the dependences obtained: the substrate temperature, the particle size in the initial HA powder, and the composition of the plasma gases.

The effect of microstructure and mechanical properties on sliding wear and cavitation erosion of plasma coatings sprayed from Al2O3 + 40 wt% TiO2 agglomerated powders

This paper discusses the influence of 40 wt% TiO2 addition to Al2O3 and the selection of plasma spray parameters on the morphology, microstructure, microhardness and adhesion of coatings. Mainly, the tribological behavior and cavitation erosion performance of produced coatings were evaluated. First, the two-factorial design of the experiment, with the stand-off distance and torch scan speed as variables, was used to plan coating deposition by means of atmospheric plasma spraying (APS). Then, a process response using a multiple regression method was used to investigate the influence of factors variation on coatings functional properties. Although these properties were already investigated in alumina-titania coatings, there are still some knowledge gaps. Particular attention was given to the composition of Al2O3 + 40 wt% TiO2, because, so far, it is the most rarely discussed in the literature in terms of, e.g., cavitation or wear resistance. Increasing the torch scan speed and decreasing the spraying distance densifies the microstructure and increases coating's mechanical properties. A dense and low porosity structure facilitates cavitation erosion resistance and minimizes friction coefficient. Cavitation erosion damage relies on brittle cracking initiated at coatings porosity. Therefore, coatings with decreasing porosity show layer-like removal contrary to uniform material removal stated for porous coatings. The sliding wear mechanism has been dominated by abrasive wear and fatigue cracking. Accumulated wear debris undergoes adhesive smearing and removal.

Application of Laser Thermocycling to Improve the Quality of Plasma Wear-Resistant Coatings

The problem of the article is designed to reveal the proposed, developed and researched new method of improving the adhesion strength of plasma wear-resistant coatings on the outer surfaces of weapons made of high-alloy, heat-resistant steels, using additional cyclic (3-4) times their heating by laser radiation to temperatures of 0.6 – 0.8Tpl for a few milliseconds. The purpose of increasing the resource of use and the quality of the appearance of the weapon by applying wear-resistant coatings with increased adhesion strength to the base using plasma gas-thermal spraying followed by laser thermal cycling. Determination of the main factors and parameters of the process of laser thermocycling of plasma coatings, their interrelationships, development of an algorithm for determining the conditions of laser thermocycling, establishment of the rational range of their values by mathematical modeling and experimental research. The results of mathematical modeling of laser cyclic heating of plasma coatings of HTN of different thicknesses are presented, which allows determining the irradiation parameters that ensure their heating to temperatures at the "coating-substrate" boundary ≤1000ºС, on the surface - to Т< Тpl, at maximum cooling rates. It has been proven that laser thermocycling provides an increase in the adhesion strength of coatings to the base from 14–18 to 90–110 MPa, a decrease in porosity from 10–12% to 7–8%, which is due to the redistribution of alloying components at the “coating–base” interface, with the formation of elements of the metallurgical connection, contributes to a significant increase in wear resistance and a decrease in the coefficient of friction due to the formation of secondary ultradispersed film structures. We consider laser thermocycling of plasma coatings is an effective method of improving their quality and strength of adhesion to the base.