The paper presents the results of studies of hybrid composite layers Ni/Al2O3/Cgraphite produced by the electrodeposition method. Three variants of hybrid composite layers were prepared in ...electrolyte solutions with the same amounts of each dispersion phases which were equal to 0.25; 0.50 and 0.75 g/dm3. The structure of Ni/Al2O3/Cgraphite layers as well as the Al2O3 and graphite powders, which were used as dispersion phases was investigated. The results of morphology and surface topography of produced layers are presented. The modulus of elasticity and microhardness of the material of produced layers were determined by DSI method. Tribological and corrosion resistance tests of produced layers were carried out. Realized studies have shown that the material of the produced layers is characterized by a nanocrystalline structure. Incorporation of dispersion phases into the nickiel matrix increases the degree of surface development of layers. Ni/Al2O3/Cgraphite layers are characterized by high hardness and abrasion resistance by friction, furthermore, they provide good corrosion protection for the substrate material.
The report presents research efforts on the synthesis of Zn/MoS2 composite coatings by electrochemical reduction from a sulphate-borate bath containing MoS2 powder as a dispersion phase at various ...concentrations. The structure of the Zn/MoS2 composite coatings was characterised and the effect of MoS2 particles embedded on their microhardness was evaluated. The coatings produced are characterized by a compact, homogeneous structure and a good connection to a steel substrate. The incorporation of MoS2 particles into the zinc matrix has an influence on the structure and morphology of the Zn/MoS2 composite coatings. It was found that the presence of MoS2 particles increases surface roughness along with coating hardness. The incorporation of the MoS2 particles into the zinc matrix slightly improves the corrosion resistance compared to Zn coatings, making the corrosion potential shift towards more electropositive values.
The paper presents the results of research on nanocomposite nickel/graphene oxide (Ni / GO) coatings produced by electrochemical reduction method on a steel substrate. Discussed is the method of ...manufacturing composite coatings with nickel matrix and embedded graphene oxide flakes. For comparative purposes, the studies also included a nanocrystalline Ni coating without embedded graphene oxide flakes. Graphene oxide was characterized by Raman spectroscopy, infrared spectroscopy (FTIR) and transmission (TEM) and scanning (SEM) electron microscopy. Results of studies on the structure of nickel and composite Ni/GO coatings deposited in a bath containing different amount of graphene oxide are presented. The coatings were characterized by scanning electron microscopy, light microscopy, Raman spectroscopy and X-ray diffraction. The adhesion of the prepared coatings to the substrate was examined by the scratch method. The microhardness of the coatings was measured using the Vickers method on perpendicular cross-sections to the surface. Corrosion tests of the coatings were investigated using the potentiodynamic method. The influence of graphene oxide on the structure and properties of composite coatings deposited from baths with different content of graphene oxide was determined.
This paper presents the results of research of Ni/diamond composite coatings produced by electrochemical reduction method. Research was focused on composite coatings with nickel matrix and diamond as ...a disperse phase and for comparison purposes on nanocrystalline nickel coatings. Ni/diamond composite coatings were produced in baths with different content of nanodiamond powder. The structures of the dispersed phase and the composite coatings were analysed by using X-ray diffraction, scanning electron microscopy and light microscopy. Measurements of selected properties of the coatings were performed, including roughness, microhardness, adhesion and abrasive wear resistance. The research results indicate that the produced coatings have a compact structure and good adherence to steel substrate. Moreover, nanocrystalline Ni/diamond composite coatings exhibit greater hardness and reduced abrasive wear resistance compared to nanocrystalline nickel coatings.
The results of research on preparations of alloy Ni-B/B composite coatings produced by chemical reduction method on a carbon steel substrate are collected in this paper. The alloy Ni-B coatings were ...also investigated for comparative purposes. The produced coatings were subjected to a heat treatment process. The boron powder with the particles size below 1 µm was used as the dispersion phase. The structure of the coatings was examined by X-ray diffraction method. Boron powder particles as well as surface morphology and topography were characterized by scanning electron microscopy. The roughness test, microhardness and corrosion resistance by potentiodynamic method and surface wettability tests were carried out. Analysis of the chemical composition by the EDS method showed that the boron powder particles were evenly embedded in the entire volume of the coating. Ni-B/B composite coatings are characterized by higher hardness than alloy Ni-B coatings. As a result of heat treatment, the Ni3B phase crystallized, which increased the hardness of the coating material. The incorporation of boron powder particles and heat treatment reduce the corrosion resistance of coatings. All produced coatings exhibited hydrophobic properties.
The layers based on chromium nitride were produced on the AZ91D magnesium alloy using a hybrid surface treatment. The treatment consists of nitriding of the chromium-precoated magnesium alloy. The ...proposed treatment yields diffusive, composite gradient-type chromium nitride layers which are diffusion-bonded to the substrate. The effect of these layers on the corrosion behavior of the AZ91D magnesium alloy was investigated by the potentiodynamic and impedance spectrometry methods. It was found that the formation of the diffusive, composite chromium nitride layers on the AZ91D alloy may result in a significant decrease of the corrosion activity measured by the corrosion potential. This effect is correlated with the layer thickness and becomes significant with relatively thin layers (less than 1 μm thick). Moreover, with the thin layers the impedance modulus is the highest and phase angle has a beneficial character.
► Hybrid method allows to produce diffusive chromium nitride layers on magnesium alloys. ► Chromium nitride layers on AZ91D alloy improve corrosion resistance. ► The best corrosion resistance occur when the CrN layers are sufficiently thin.
This study aimed to examine the distribution of predefined phenotypes, demographic data, clinical outcomes, and treatment of patients who were included in the Polish cohort of the Phenotypes of COPD ...in Central and Eastern Europe (POPE) study.
This was a sub-analysis of the data from the Polish cohort of the POPE study, an international, multicenter, observational cross-sectional survey of COPD patients in Central and Eastern European countries. The study included patients aged >40 years, with a confirmed diagnosis of COPD, and absence of exacerbation for at least 4 weeks before study inclusion. A total of seven Polish centers participated in the study.
Among the 430 Polish COPD patients enrolled in the study, 61.6% were non-exacerbators (NON-AE), 25.3% were frequent exacerbators with chronic bronchitis (AE CB), 7.9% were frequent exacerbators without chronic bronchitis (AE NON-CB), and 5.1% met the definition of asthma-COPD overlap syndrome (ACOS). There were statistically significant differences among these phenotypes in terms of symptom load, lung function, comorbidities, and treatment. Patients with the AE CB phenotype were most symptomatic with worse lung function, and more frequently reported anxiety and depression. Patients with the ACOS phenotype were significantly younger and were diagnosed with COPD earlier than those with other COPD phenotypes; those with the ACOS phenotype were also more often atopic and obese.
There is significant heterogeneity among COPD patients in the Polish population in terms of phenotype and clinical outcome. The non-exacerbator phenotype is observed most frequently in Poland, while the frequent exacerbator with chronic bronchitis phenotype is the most symptomatic.
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