Dissertations / Theses on the topic 'Покриття каталітичні'
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Красовська, Л. А., and Борис Іванович Байрачний. "Дослідження процесу електрохімічного отримання сплаву Fe-Cо." Thesis, НТУ "ХПІ", 2007. http://repository.kpi.kharkov.ua/handle/KhPI-Press/20619.
Full textБулгакова, Анастасія Сергіївна. "Електрохімічний імпеданс композиційного покриття Cо-Mо-TіO₂." Thesis, Харківський національний університет міського господарства ім. О. М. Бекетова, 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/43143.
Full textСмирнова, Олександра Юріївна, and Вікторія Володимирівна Штефан. "Каталітична активність церійвмісних оксидних шарів на сплаві титану ОТ4-0." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/48587.
Full textХижняк, Володимир Олександрович, and Ігор Володимирович Парсаданов. "Комплексна оцінка паливно-екологічних показників дизеля при використанні каталітичних покриттів." Thesis, НТУ "ХПІ", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/38495.
Full textГапон, Юліана Костянтинівна. "Функціональні покриття тернарними сплавами кобальту з тугоплавкими металами." Thesis, НТУ "ХПІ", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/27602.
Full textThesis for the Degree of Candidate of Technical sciences in specialty 05.17.03 – Technical Electrochemistry. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2017. The thesis is devoted to development of technologies for galvanic coatings synthesis of the ternary alloys cobalt-molybdenum-tungsten from poly-ligand electrolytes to produce materials with improved physical and mechanical properties. The constant instability and composition of mono- and bi-ligand complexes of cobalt are determined, and both citrate-diphosphate and ammonia-citrate systems suggested for the deposition of cobalt alloys with tungsten and molybdenum. The mechanism of alloy deposition is defined based on kinetic patterns analysis. Metals recovered by stages from hetero-nuclear complexes of composition [MO₄Со(P₂O₇)]⁴⁻ and mononuclear Со(Cit)₂⁴⁻ (where M = Mo, W) when deposited from citrate-diphosphate bath. Conjugate deposition of metals in alloy from ammonia-citrate electrolyte occurred from complexes [MO₄Со(Cit)]³⁻. The effect of electrolytes composition and deposition modes (stationary and pulse) on the components content, morphology, structure and functional properties of alloys as well as process efficiency are substantiated. A technological scheme for functional electrolytic cobalt alloy coatings deposition with molybdenum and tungsten is offered and relevant technological instructions are developed. It was established high corrosion resistance coatings, synergic growth of microhardness and catalytic activity compared with alloying components.
Гапон, Юліана Костянтинівна. "Функціональні покриття тернарними сплавами кобальту з тугоплавкими металами." Thesis, НТУ "ХПІ", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/27601.
Full textThesis for the Degree of Candidate of Technical sciences in specialty 05.17.03 – Technical Electrochemistry. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2017. The thesis is devoted to development of technologies for galvanic coatings synthesis of the ternary alloys cobalt-molybdenum-tungsten from poly-ligand electrolytes to produce materials with improved physical and mechanical properties. The constant instability and composition of mono- and bi-ligand complexes of cobalt are determined, and both citrate-diphosphate and ammonia-citrate systems suggested for the deposition of cobalt alloys with tungsten and molybdenum. The mechanism of alloy deposition is defined based on kinetic patterns analysis. Metals recovered by stages from hetero-nuclear complexes of composition [MO₄Со(P₂O₇)]⁴⁻ and mononuclear Со(Cit)₂⁴⁻ (where M = Mo, W) when deposited from citrate-diphosphate bath. Conjugate deposition of metals in alloy from ammonia-citrate electrolyte occurred from complexes [MO₄Со(Cit)]³⁻. The effect of electrolytes composition and deposition modes (stationary and pulse) on the components content, morphology, structure and functional properties of alloys as well as process efficiency are substantiated. A technological scheme for functional electrolytic cobalt alloy coatings deposition with molybdenum and tungsten is offered and relevant technological instructions are developed. It was established high corrosion resistance coatings, synergic growth of microhardness and catalytic activity compared with alloying components.
Гапон, Юліана Костянтинівна, Микола Дмитрович Сахненко, Марина Віталіївна Ведь, and Т. О. Ненастіна. "Ресурсозаощаджувальна екологічно безпечна технологія нанесення покриттів сплавом кобальт-молібден-вольфрам з високими функціональними властивостями." Thesis, Государственное предприятие "Украинский научно-технический центр металлургической промышленности "Энергосталь", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/33264.
Full textМайзеліс, Антоніна Олександрівна. "Електрохімічні функціональні покриття з мікро- і нанорозмірними Cu, Sn, Ni, Zn-вмісними шарами керованого фазового складу." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2020. http://repository.kpi.kharkov.ua/handle/KhPI-Press/48963.
Full textThesis for the Doctor’s of Science degree in Technical Sciences by speciality 05.17.03 – Technical Electrochemistry (16 – Chemical and Bioengineering). – National Technical University “Kharkiv Polytechnical Institute”, 2020. The object of study is electrochemical processes of formation of coatings consisting of micro- and nanosized Cu, Sn, Ni, Zn-containing layers of controlled phase composition. The subject of the study is the kinetic regularities of the processes of formation of Cu, Sn, Ni, Zn-containing layers of coatings of controlled phase composition in polyligand electrolytes and their physical-mechanical, anticorrosive and catalytic properties. The thesis is devoted to the development of theoretical principles of increasing the functional properties of surface materials by alternating electrodeposition of nano and micro-sized layers of Cu, Sn, Ni, Zn-containing alloys. The main principle is the priority of use of polyligand electrolytes with the creation of conditions for the deposition of layers of different phase composition (LDPC) in order to influence the micro- and macro structure of sediments and improve the barrier anticorrosive and mechanical properties of coatings by periodically changing nucleation conditions and creation of intermetallics-enriched interlayer boundaries. Based on the determination of kinetic regularities of electrode processes in the М-P₂O₇⁴⁻-Cit³⁻, М-P₂O₇⁴⁻-Y⁴⁻, M-NH₃-Gly systems, the advantage of using polyligand electrolytes for monolithic electrolyte coatings for LDPC coatings has been proved due to possibility of depositing thin layers of different phase composition from one electrolyte, the instantaneous mechanism of nucleation with the formation of thin continuous films by layer-by-layer deposition of alloys, expanding the range of allowable current densities of dissolution of metals in the combined anodes in terms of periodic changes in current density in a wide range of values. It is determined that the compatible discharge of ions of all metals in the studied polyligand electrolytes is accompanied by concentration complications with the presence of adsorption phenomena at low current density of alloy film deposition and influence of kinetic constraints associated with the chemical stage of complex dissociation are observed at high current density. Based on the analysis of model polarization dependences obtained by nonlinear potential change according to experimentally obtained data, a new method of quantitative determination of contact exchange parameters in electrolytes is proposed. The clear correspondence of these dependences to the experimentally determined change in the potential of the total process with a discreteness of up to 1 mV and 0.05 s, taking into account its direction and speed change, allows to increase the accuracy of determining the parameters of conjugate processes. The algorithm for quantitative determination of the elemental and phase composition of Zn-Ni alloy films on the basis of the proposed mechanism of anodic dissolution of thin layers of Zn-Ni alloy under conditions of stripping voltammetry is substantiated. In the process of anodic treatment of thin layers of Zn-Ni alloy in alkaline ammonia-glycinate solution, sequential dissolution of zinc phase, zinc from δ- and γ-phase of alloy of different structure, accompanied by nickel-enriched residue and matrix nickel dissolution. The relationship between the content of intermetallic compounds and the initial structure of the γ-phase with the composition of the nickel-enriched residue on the electrode is determined, which allows increase the accuracy of quantitative determination of the composition of the layers. The sequential oxidation peaks of the phases present in Cu-Zn, Cu-Sn and Zn-Ni alloys deposited from the investigated electrolytes during voltammetric dissolution of the alloy films were identified and confirmed by XRD. The dependences of the chemical and phase composition of the alloy layers on the electrolyte composition and the electrolysis regime using the method of stripping voltammetry are established. The design of the architecture of coatings with layers of different phase composition was performed on the basis of analysis of changes in the phase composition of alloy layers in thickness, the effect of alternating deposition of alloy layers on the coating composition of LDPC, certain variants of phase composition of belayer. The constituent layers consist of the following phases: (Cu-Zn)base - mainly α-phase, (Cu-Zn)add – (α, β-, ε- and γ-phases, and Zn); (Cu-Sn)base – in addition to α-phase contains ε- and η-phases, do not contain Sn-phase, (Cu-Sn)add - in addition to α-phase contain Sn-phase and η-phase, and ε-phase is absent; (Zn-Ni)base contain the Zn phase, δ- and γ-phases, (Zn-Ni)add - additionally contain X-ray amorphous β-phase and Ni-phase. Analysis of XRD coatings with layers of different phase composition showed the presence of a significant amount of intermetallics in the composition of coatings with the size of the regions of coherent scattering for the main phases 9-10 nm. The SEM method shows that the developed coatings have a uniform and fine-crystalline surface structure with dense packing of grains and in the absence of pores. The relationship between the nature of the influence of the electrolyte composition, electrolysis regime and architecture of coatings [(M₁-M₂)base/(M₁-M₂)add]n and their microhardness and corrosion resistance is determined. It is proved that the indicators of corrosion resistance and microhardness of the developed coatings exceed the indicators of single-layer coatings by base alloys, which are deposited in the same electrolytes. The microhardness is extremely dependent on the coating architecture. The maximum microhardness of the developed coatings is 397-428 HV for [(Cu-Zn)base/(Cu-Zn)add]n, 476-511 HV for [(Cu-Sn)base/(Cu-Sn)add]n, and 700-864 HV for [(Zn-Ni)base/(Zn-Ni)add]n at a bilayer thickness of 20-125 nm. It was found that the cathodic vs. steel LDPC coating, consisting of Cu-Zn and Cu-Sn alloys are non-porous at a thickness of 0.63 μm and 2.3 μm, respectively. In conditions of prolonged exposure in a solution of 3.5% NaCl anode coatings [(Zn-Ni)base/(Zn-Ni)add]n retain protective properties on steel 1.5-2.6 times longer compared to single-layer coatings. The influence of electrolyte composition, potential and deposition time sublayers deposition [(M₁-M₂-(M₃))/(Mi-Mj(OH)₂)]n (i = 1-3) coatings on the parameters of their catalytic activity in test hydrogen evolution reactions and oxidation of organic substances and performance characteristics are was established. It was determined that the obtained electrodes show greater corrosion resistance and have a higher catalytic activity, compared with electrodes coated with the corresponding alloys: [(Ni-Cu)/(Mi-Mi(OH)₂]n after cathodic treatment, and [(Ni-Zn-Cu)/(Mi-Mi(OH)₂)]n, after chemical and electrochemical treatment – in hydrogen evolution reaction in alkaline solution; [(Ni-Cu)/(Mi-Mi(OH)₂-MiOOH)]n after cycling in the region of potentials for the reverse transition of hydroxide to oxyhydroxide – in the oxidation reactions of alcohols and glucose, coating [(Sn-Sb)/(M-MₓОᵧ)]n, after dehydration and anodic oxidation – in the oxidation reaction of phenol. According to the results of scanning electron microscopy, the hierarchically developed surface of the electrodes, consisting of dendrites covered with conglomerates of globular shape was identified. It was found that the [(Ni-Zn-Cu)/(Mi-Mi(OH)₂)]n coating with a lower content of zinc phase and γ-phase, after treatment in an alkali solution, have a lower development coefficient, but a higher current density in hydrogen evolution reaction (1.81 mA/cm² vs. 1.28 mA/cm²), lower ohmic resistance and more mechanically strong hierarchically developed surface. It was found that the electrode coated with [Ni(Cu)/(Mi-Mi(OH)₂-MiOOH)]n with micro-dimensional layers, in comparison with the electrode coated with nanoscale layers, has a higher heterogeneous velocity constant (0.53 compared with 0.36 s⁻¹) and the best operational properties, due to creation of a strong microshell of alloy at a nanostructured surface. Sensory properties of the electrode coated with [(Ni-Cu)/(Mi-Mi(OH)₂-MiOOH)]n are detected: hypersensitivity at a glucose concentration up to 50 μmol/dm³ 13986±9 μA(mmol/dm³)⁻¹ cm⁻², sensitivity in the range from 0.05 mmol/dm³ to 1.65 mmol/dm³ 2921±1 μA (mmol/dm³)⁻¹ cm⁻², up to 6,3 mmol/dm³ (at +0.6 V) – 1667±4 μA (mmol/dm³)⁻¹ cm⁻². Technological parameters of electrochemical processes of resource-saving formation of micro- and nanostructured protective coatings of [(Cu-Zn)base/(Cu-Zn)add], [(Cu-Sn)base/(Cu-Sn)add]n and [(Zn-Ni)base/(Zn-Ni)add]n, and non-platinum catalytically active electrode materials [(Ni-Cu)/[Mi-Mi(OH)₂]n, [(Ni-Zn-Cu)/(Mi-Mi(OH)₂)], [(Ni-Cu)/(Mi-Mi(OH)₂)MiOOH)]n and [(Sn-Sb)/(Mi-MₓОᵧ)]; additional layer of Zn-Ni alloy in electrolyzers with low concentrated electrolytes to protect the zinc coating from corrosion. The combination of functions of electrodeposition of additional layers of alloys, anode processing and electroextraction of metals is taken into account, which allows saving production areas, metals, water and electricity. High mechanical and anticorrosive properties of coatings with LDPC were confirmed by LSC "FED", SPE "Ecopolymer", Kharkiv Aero Club named by V. S. Grizodubova APO OPD Ukraine. Technological processes of electrodeposition of protective and catalytic act coatings were tested and recommended for the implementation at SScPE "Kommunar Corporation" and SE "Malyshev Plant".
Майзеліс, Антоніна Олександрівна. "Електрохімічні функціональні покриття з мікро- і нанорозмірними Cu, Sn, Ni, Zn-вмісними шарами керованого фазового складу." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2020. http://repository.kpi.kharkov.ua/handle/KhPI-Press/48940.
Full textThesis for granting the Degree of Doctor of Technical sciences in speciality 05.17.03 – Technical Electrochemistry. – National Technical University “Kharkiv Polytechnical Institute”, 2020. The dissertation is devoted to the development of theoretical bases of technologies of electrochemical formation of protective and functional coatings with alternate deposition of micro- and nanoscale layers of alloys of different composition on the basis of experimentally proved fidelity of the hypothesis about possibility of control of properties of coatings by deposition of layers of alloys of different phase composition (LDPC) that meet the full set of quality requirements for the corresponding single-layer coatings, and additional layers of alloys of another phase composition with enhanced specified characteristics. Based on the determination of kinetic laws of electrode processes in the systems М-P₂O₇⁴⁻-Cit³⁻, М-P₂O₇⁴⁻-Y⁴⁻, M-NH₃-Gly, the advantage of using polyligand electrolytes in comparison with monoligand ones is shown and the dependences of chemical and phase composition of alloy films on the concentration ratio of metal ions and electrolysis mode are revealed. It is shown that the minimum thickness of the constituent films of alloys is limited by the need to ensure their continuity in the case of compact functional coatings, and the need to ensure mechanical stability in the case of hierarchically developed electrode materials. The optimal thickness of the layers is determined by the nature of changes in the chemical and phase composition of the films of alloys with thickness. Electrolytes for coating deposition should provide: separation of ranges of deposition potentials of different elemental and phase composition> 100 mV; the absence of dissolution of the electronegative layers, or the dissolution of the unwanted electronegative phase of them, in the process of deposition of more positive layers; anodic dissolution in the semi-passive state of a more negative metal and active dissolution of a more positive metal under conditions of periodic changes in current density in its wide range. A new method for determining the parameters of contact exchange has been developed, which is based on the analysis of model polarization dependences obtained by nonlinear potential change according to experimentally obtained data on the change of stationary potential of electronegative surface taking into account its direction and velocity change which allows you to more accurately control the process of interaction of the electrode surface with the electrolyte in the absence of current. The algorithm for quantitative determination of the elemental and phase composition of Zn-Ni alloy films with the use of stripping voltammetry in an alkaline ammonia-glycinate electrolyte is proposed. The mechanism of anodic dissolution of thin films of Zn-Ni alloy in alkaline ammonia-glycine solution is proposed, which consists in sequential dissolution of free zinc, zinc from δ- and γ-phases of alloy of different structure, then Ni-enriched residue and matrix Ni. The relationship between the content of intermetallics and the composition of the Ni -enriched residue on the electrode is shown, which allows to increase the accuracy of quantitative determination of the film composition. It is proved that the indicators of corrosion resistance and microhardness of coatings with LDPC exceed the properties of single layer coatings of base alloys deposited in the same electrolytes, which is most evident in the conditions of long-term operation. It is proved that in comparison with the alloy coating, the [[Cu-Ni)/(M-M(OH)₂)]n coating has improved characteristics in the hydrogen evolution reaction. High catalytic activity in the reaction of hydrogen evolution of an electrode coated with [(Ni-(Zn)-Cu)/(М-M(OH)₂)]n followed by chemical and electrochemical treatment in an alkali solution is shown. The increased stability and catalytic activity of electrode materials with (Nі-Cu)/(M-M(OH)₂-MOOH) and (Sn-Sb)/(MₓОᵧ) coatings in test reactions of organic substances (methanol, ethanol, glucose, phenol) oxidation in comparison with single-layer are proven. New methods of electrodeposition of LDPC protective [(Cu-Zn)баз/(Cu-Zn)дод]n, [(Cu-Sn)баз/(Cu-Sn)дод]n, [(Zn-Ni)баз/(Zn-Ni)дод]n coatings and catalytically active [(Ni-(Zn)-Cu)/(М-M(OH)₂)]n, [(Nі-Cu)/(М-M(OH)₂-МООН] and [(Sn-Sb)/(М-MₓОᵧ)]n coatings with improved characteristics in comparison with existing similar materials are proposed. Technological processes of electrodeposition of LDPC coatings are tested on experimental batches and recommended for implementation.
Єрмоленко, Ірина Юріївна. "Наукові основи електрохімічної технології покриттів тернарними сплавами заліза з тугоплавкими металами." Thesis, НТУ "ХПІ", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37459.
Full textDissertation for the Degree of the Doctor of Engineering Sciences in the Specialty of 05.17.03 – Technical Electrochemistry. – National Technical University "Kharkіv Polytechnic Institute", Kharkіv, 2018. This doctoral thesis is devoted to the development of scientific basics for electrochemical technologies used for the application of coatings consisting of ternary iron and cobalt alloys combined with molybdenum and tungsten of improved functionality. The hypothesis as for the competitive reduction of iron ternary metals with refractory components preconditioned by the mutual interaction of thermal-&-dynamic and crystal-&-chemical characteristics of the alloy-forming metals and the kinetic parameters of cathode process and it was proved experimentally. The kinetic regularities of the co-reduction in Fe³⁺ ‒ MoO₄²⁻ ‒ WO₄²⁻ ‒ Cit³⁻, Fe³⁺ ‒ Со²+ ‒ WO₄²⁻ (MoO₄²⁻) ‒ Cit³⁻ systems have been defined and the mechanism of deposition of ternary Fe-Mo-W, Fe-Co-W (Mo) alloys has been substantiated. The influence of composition of electrolytes and modes of electrolysis on elemental, phase composition and surface morphology of the obtained coatings has been deter-mined. The possibility of controlling the composition and morphology of multicomponent coatings on the basis of iron and cobalt by varying the composition of the electrolyte (the ratio of component concentrations, the ratio of ligand and complexing agent), and by used of galvanostatic and pulsed electrolysis regimes with a ranging of current density 2.5 ‒ 6.5 A/dm², and durations pulse/pause 5 ‒ 10 / 5 ‒ 20 ms, has been proved. The electrolytes and the deposition modes were developed that provide the deposition of Fe-Co-W coatings with the Co content of 32 to 47 аt. %, and W of 5 to 13 аt. %, and Fe-Mo-W coatings with the tungsten content of 5 to 11 at. %, and the molybdenum contents of 26 to 32 at. %, and the Fe-Сo-Мо coatings with the Co content ranging from 26 to 48 at. %, and Mo content ranging from 15 to 31 at. %, and the current efficiency ranging from 58 to 82 %. The variation schemes of electrochemical processes were suggested and these allow for the deposition of Fe-Mo-W and Fe-Co-W(Мо) coatings depending on their practical application. The perspective directions of the application of the obtained materials according to the results of experimental researches and tests of functional properties in model environments and technological conditions are determined.
Єрмоленко, Ірина Юріївна. "Наукові основи електрохімічної технології покриттів тернарними сплавами заліза з тугоплавкими металами." Thesis, НТУ "ХПІ", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37455.
Full textDissertation for the Degree of the Doctor of Engineering Sciences in the Specialty of 05.17.03 – Technical Electrochemistry. – National Technical University "Kharkіv Polytechnic Institute", Kharkіv, 2018. This doctoral thesis is devoted to the development of scientific basics for electrochemical technologies used for the application of coatings consisting of ternary iron and cobalt alloys combined with molybdenum and tungsten of improved functionality. The hypothesis as for the competitive reduction of iron ternary metals with refractory components preconditioned by the mutual interaction of thermal-&-dynamic and crystal-&-chemical characteristics of the alloy-forming metals and the kinetic parameters of cathode process and it was proved experimentally. The kinetic regularities of the co-reduction in Fe³⁺ ‒ MoO₄²⁻ ‒ WO₄²⁻ ‒ Cit³⁻, Fe³⁺ ‒ Со²+ ‒ WO₄²⁻ (MoO₄²⁻) ‒ Cit³⁻ systems have been defined and the mechanism of deposition of ternary Fe-Mo-W, Fe-Co-W (Mo) alloys has been substantiated. The influence of composition of electrolytes and modes of electrolysis on elemental, phase composition and surface morphology of the obtained coatings has been deter-mined. The possibility of controlling the composition and morphology of multicomponent coatings on the basis of iron and cobalt by varying the composition of the electrolyte (the ratio of component concentrations, the ratio of ligand and complexing agent), and by used of galvanostatic and pulsed electrolysis regimes with a ranging of current density 2.5 ‒ 6.5 A/dm², and durations pulse/pause 5 ‒ 10 / 5 ‒ 20 ms, has been proved. The electrolytes and the deposition modes were developed that provide the deposition of Fe-Co-W coatings with the Co content of 32 to 47 аt. %, and W of 5 to 13 аt. %, and Fe-Mo-W coatings with the tungsten content of 5 to 11 at. %, and the molybdenum contents of 26 to 32 at. %, and the Fe-Сo-Мо coatings with the Co content ranging from 26 to 48 at. %, and Mo content ranging from 15 to 31 at. %, and the current efficiency ranging from 58 to 82 %. The variation schemes of electrochemical processes were suggested and these allow for the deposition of Fe-Mo-W and Fe-Co-W(Мо) coatings depending on their practical application. The perspective directions of the application of the obtained materials according to the results of experimental researches and tests of functional properties in model environments and technological conditions are determined.
Штефан, Вікторія Володимирівна. "Електрохімічні процеси в технології функціональних молібден- та вольфрамвмісних покриттів." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/41358.
Full textThesis for granting the Degree of Doctor of Technical sciences in speciality 05.17.03 – Technical Electrochemistry. – National Technical University "Kharkiv Politechnical Institute", 2019. The dissertation is devoted to the development of scientific principles of electro-chemical processes in the technology of functional molybdenum and tungsten-containing coatings. The hypothesis of the possibility of controlling the nature of electrochemical processes, with the participation of molybdenum (VI) ions and tungsten (VI) associated with the achievements in the study of the state of the forms of their ions in aqueous solutions is formed and experimentally proved. The influence of the nature of molybdenum oxyanion on the kinetics of cathode processes in complex electrolytes within a wide range of pH: ammonium pyrophosphate (pH> 7) and ammonia-trilonate (pH <7) is proved. The understanding of the controlled influence with the form of molybdenum oxoanions on the polarization of the cathode process for the change of the limiting stage is developed. It has been confirmed that the cathode processes in the precipitation of the Co-Mo alloy include the restoration of molybdenum oxoanions due to not only the electrochemical stage but with the participation of oxi-dation-reduction reactions in which the reduction products are those of combined electrode reactions - cobalt and adsorbed hydrogen. The influence of the electrolytes composition and electrolysis parameters on functional properties of coatings (corrosion resistance, microhardness, catalytic activity in the reaction of CO conversion and electrochemical hydrogen release) is determined. The compositions of electrolytes are treated experimentally to create conversion coatings on silver surfaces and D16 alloy. It is proved that the change of pH in the electrolyte of the anode-oxide coating on the D16 alloy changes the form of oxoanions and increases the corrosion re-sistance of the system. It is established that with the thiosulfate concentration in-crease, the silver potential moves toward negative values due to the formation of [Ag(S2O3)n](2n+1)-, which allows the process of oxidation-reduction reactions involv-ing tungsten and silver polyanions. The use of a silver surface tester on the basis of tungstate is 2 times more efficient than a chromate-based passivator. A catalyst is obtained for the Ti|TiOx·WOp·CeOy·ZrOz·CuOn composition, which is characterized by high conversion activity of CO (up to 95% at 420 °C). Anodic oxide coatings on OT4-0 containing molybdenum compounds exhibit suppressed conductivity and heat resistance of the anode layer. The oxide coatings formed from the molybdenum-containing electrolyte on a steel 08Х18Н10 have an electrical resistance of 2.6·1010…3.6·1010 Ω. The effectiveness of scientific study is proved by the positive results of laboratory and industrial testing and implementation.
Каракуркчі, Ганна Володимирівна. "Науково-технологічні засади плазмо-електролітного формування гетерооксидних покриттів для екотехнологій." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2020. http://repository.kpi.kharkov.ua/handle/KhPI-Press/48802.
Full textThesis for scientific degree of Doctor of Technical Sciences in the Specialty of 05.17.03 – Technical Electrochemistry (161 – Chemical Technology and Engineering). – National Technical University "Kharkіv Polytechnic Institute", Kharkіv, 2020. The thesis is devoted to the development of scientific bases of plasma-electrolytic formation of heterooxide coatings of a given composition and functional properties on Al (Ti) alloys for ecotechnologies. Hypotheses were generated and experimentally proved concerning the homogenization of the surface of aluminum (titanium) multicomponent alloys and the formation of a given relief of the oxide matrix by plasma-electrolyte oxidation in alkaline solutions of diphosphates and the formation of strongly adhesed heteroxide coatings with a wide range of functional properties on aluminium (titanium) alloys by executing plasma-electrolytic oxidation in alkaline solutions of diphosphates with the presence of dopant metal compounds in one technological process. With the use of differential dependences dU/dt–U in order to describe the kinetic laws and establish the stages of the process of plasma-electrolytic oxidation of alloys of different chemical composition. It found that the use of complex electrolytes based on alkali metal allows to reduce the content of alloying components in the surface layers by 4–5 times and to form developed oxide matrix of the metal-carrier. It proved that in the mode of "decreasing power" with variation of current density heteroxide oxide coatings with Ѡ(Mn) up 36.0 аt. % and with Ѡ(Co) up 24.0 аt. %, that allowed to determine the optimal synthesis conditions. The formation of matrix of metal-carrier in proposed modes, in which oxides of dopant metals of variable valence are incorporated, is confirmed. It is proved that heat treatment of heteroxide coatings at temperatures up 600°C causes a change in the ratio of oxide forms of alloying components while maintaining high microhardness values. It is established that one-stage plasma-electrolyte treatment of the KamAZ-740 engine piston in in developed electrolytes and modes allows to form uniform strongly adhered catalytic and heat-protective heteroxide coatings by oxides of manganese and cobalt, high activity of which was proved in the process of catalytic fuel combustion. The variation schemes of of plasma-electrolytic treatment of multicomponent Al (Ti) alloys with the increased content of active components and the set functional properties were suggested. The perspective areas of the application of the obtained materials according to the results of experimental researches and tests of properties in model environments and technological conditions are determined.
Штефан, Вікторія Володимирівна. "Електрохімічні процеси в технології функціональних молібден- та вольфрамвмісних покриттів." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/41356.
Full textThesis for granting the Degree of Doctor of Technical sciences in speciality 05.17.03 – Technical Electrochemistry. – National Technical University "Kharkiv Politechnical Institute", 2019. The dissertation is devoted to the development of scientific principles of electro-chemical processes in the technology of functional molybdenum and tungsten-containing coatings. The hypothesis of the possibility of controlling the nature of electrochemical processes, with the participation of molybdenum (VI) ions and tungsten (VI) associated with the achievements in the study of the state of the forms of their ions in aqueous solutions is formed and experimentally proved. The influence of the nature of molybdenum oxyanion on the kinetics of cathode processes in complex electrolytes within a wide range of pH: ammonium pyrophosphate (pH> 7) and ammonia-trilonate (pH <7) is proved. The understanding of the controlled influence with the form of molybdenum oxoanions on the polarization of the cathode process for the change of the limiting stage is developed. It has been confirmed that the cathode processes in the precipitation of the Co-Mo alloy include the restoration of molybdenum oxoanions due to not only the electrochemical stage but with the participation of oxi-dation-reduction reactions in which the reduction products are those of combined electrode reactions - cobalt and adsorbed hydrogen. The influence of the electrolytes composition and electrolysis parameters on functional properties of coatings (corrosion resistance, microhardness, catalytic activity in the reaction of CO conversion and electrochemical hydrogen release) is determined. The compositions of electrolytes are treated experimentally to create conversion coatings on silver surfaces and D16 alloy. It is proved that the change of pH in the electrolyte of the anode-oxide coating on the D16 alloy changes the form of oxoanions and increases the corrosion re-sistance of the system. It is established that with the thiosulfate concentration in-crease, the silver potential moves toward negative values due to the formation of [Ag(S2O3)n](2n+1)-, which allows the process of oxidation-reduction reactions involv-ing tungsten and silver polyanions. The use of a silver surface tester on the basis of tungstate is 2 times more efficient than a chromate-based passivator. A catalyst is obtained for the Ti|TiOx·WOp·CeOy·ZrOz·CuOn composition, which is characterized by high conversion activity of CO (up to 95% at 420 °C). Anodic oxide coatings on OT4-0 containing molybdenum compounds exhibit suppressed conductivity and heat resistance of the anode layer. The oxide coatings formed from the molybdenum-containing electrolyte on a steel 08Х18Н10 have an electrical resistance of 2.6·1010…3.6·1010 Ω. The effectiveness of scientific study is proved by the positive results of laboratory and industrial testing and implementation.
Булгакова, Анастасія Сергіївна. "Технологія електроосадження функціональних покриттів Со-Мо, Со-Мо-ТіО₂." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2020. http://repository.kpi.kharkov.ua/handle/KhPI-Press/48419.
Full textThe dissertation on competition of a scientific degree of the doctor of philosophy on a specialty 161 – Chemical technologies and engineering (16 – Chemical and bioengineering). – National Technical University "Kharkiv Polytechnic Institute", Ministry of Education and Science of Ukraine, Kharkiv, 2020. The dissertation work is directed on development of technology of reception of a composite covering of Co-Mo-TiO₂ with the raised functional properties. The object of research is the processes of electrochemical production of Co-Mo and Co-Mo-TiO₂ coatings from complex electrolytes. The subject of the research is the technological parameters and kinetic regularities of electrodeposition of functional coatings of Co-Mo and Co-Mo-TiO₂ from ammonia-trilonate electrolytes. In the dissertation work the scientific and practical problem of development of processes of electrochemical reception of coverings with the raised functional properties is solved. The research was carried out using both classical and fundamentally new modern methods: the kinetics of cathodic reduction were studied by linear voltammetry (LVA) and impedance spectroscopy; the phase composition of the precipitates was determined according to X-ray phase analysis (X-ray diffraction), the surface morphology and elemental composition of the obtained samples were studied using a scanning electron microscope (SEM); the microhardness of the coatings was determined by Vickers; the catalytic activity of the coatings was tested for hydrogen evolution reactions; corrosion behavior was studied by impedance spectroscopy and polarization resistance. The introduction substantiates the relevance of research objectives, shows the relationship of work with scientific programs, plans, topics, formulates the purpose and main objectives, provides scientific novelty and practical significance of the results, determined the personal contribution of the applicant, noted approbation of the results. The first section provides an analytical review of information sources. The relevance of the topic at the level not only of the country but also of foreign schools is considered. The articles in which data on influence of structure of electrolytes and modes of electrolysis on processes of deposition of similar coverings are resulted are processed. The analysis of methods of research of functional properties of the received materials is executed. The evaluation of the presented results is carried out. The aspects to which it is expedient to pay attention at creation of a new electrolyte are covered. Based on the results of the analysis of literature data, the direction of research is chosen and the main tasks of the dissertation are formulated. The second section describes the methods of studying the coatings of Co-Mo and Co-Mo-TiO₂: – polarization studies were performed using an IPC-Pro potentiostat at a potential sweep rate of 0,001 to 0,1 V/s. – studies by impedance spectroscopy were performed using an IPC-Pro potentiostat and an FRA frequency response analyzer in the frequency range of 0,03-50 kHz; – galvanostatic electrolysis was performed using stabilized DC sources B5-50. Studies of the structure and composition of the obtained sediments were performed using modern physicochemical methods of analysis: – X-ray phase analysis of coatings was performed using the device DRON-3; – surface morphology and elemental composition of the obtained coatings were examined using a scanning electron microscope; – Vickers microhardness was determined on a PMT-3 hardness tester. Mathematical processing of experimental data was carried out by methods of experiment planning and mathematical statistics using Microsoft Office Excel software package. The third section covers the study by LVA and impedance spectroscopy of the kinetics of electrodeposition processes from simple (sulfate) and complex (ammonia-trilonate) electrolytes of coatings with cobalt and cobalt alloys, in particular Co-Mo alloy, composite coating of Co-Mo-TiO₂ and electrolyganate. Studies of this section have yielded the following results: – the process of electroreduction of cobalt ions from a simple electrolyte is irreversible. Limiting stage - charge transfer; – with the addition of ligands, molybdenum salt and titanium dioxide there is a change in the mechanism of the cathode process. The reaction mechanism is determined by a preliminary first-order chemical reaction; – the values of the order of the reaction confirmed that when adding ligands to the electrolyte, the process becomes multi-stage and complicated by intermediate stages; – calculated values of activation energy indicate that the process in the system "Na₂SO₄ - CoSO₄" is limited by the electrochemical stage, but in the formation of cobalt complexes in the electrolyte, the process is slowed down by the chemical stage; – during electrodeposition of molybdenum coating is the reduction of molybdate oxoions to intermediate oxidation states; – the results of impedance spectroscopy in the deposition of Co-Mo and Co-Mo-TiO₂ precipitates indicate the presence of kinetic and diffusion complications in the mechanism of the cathode process due to the reduction of molybdenum oxoanions according to the film adsorption theory. The fourth section substantiates the compositions of electrolytes for the production of galvanic alloy Co-Mo with the ability to control microhardness, catalytic activity and corrosion resistance by varying the molybdenum content in the alloy. The structure, phase and elemental composition of Co-Mo and Co-Mo-TiO₂ coatings have been studied. The influence of the electrolysis regime on the content of sludge components is analyzed. According to the research of this section, the following results were obtained: – current output depends on the mode of electrolysis and the concentration of electrolyte components; – the molybdenum content in the Co-Mo precipitate decreases with increasing current density and increasing pH. The highest content of Mo 85 % by weight in the alloy is observed at j = 1 A/dm² and within pH = 2–4; – the obtained coatings are well adhered to the base, sufficiently uniform and fine-crystalline; – the results of X-ray phase and elemental analysis indicate the presence in the coating of elements of cobalt, molybdenum and titanium, their compounds in the form of oxides and intermetallics in significant quantities; – the results of scanning microscopy revealed a highly developed surface structure of the composite coating; – the content of components significantly depends on the current density and pH of the electrolyte. The fifth section presents studies of functional properties, such as microhardness, catalytic activity in the reaction of hydrogen evolution in solutions with different pH values, corrosion resistance in chloride and hydroxide solutions, anodic behavior of the obtained coatings in solutions with a wide pH range. According to the results of research, the following data were obtained: – the presence of molybdenum in the electrolyte leads to an increase in the hardness of the coatings - the highest hardness of 429 kg/mm² has an alloy Co50-Mo50. In terms of microhardness (416 kgf/mm²), the composite coating of Co-Mo-TiO₂ is almost not inferior to the Co-Mo alloy; – the highest electrocatalytic activity in the reaction of hydrogen evolut ion in an aqueous solution of 0,1 M and 1 M NaOH has an alloy of Co-Mo with a molybdenum content of 25 wt. %. The introduction of titanium dioxide leads to a significant increase in the catalytic activity of Co-Mo-TiO₂ in comparison with the alloy of Co-Mo in solutions of H₂SO₄, NaOH, Na₂SO₄; – Co-Mo alloys corrosion-resistant in chloride solutions (3 % NaCl; 5 % HCl); – Co-Mo-TiO₂ coatings are corrosion-resistant in 1 M NaOH solutions and 0,1 M NaOH and 0,1 N H₂SO₄ and Na₂SO₄ solutions; – the anodic behavior of coatings containing molybdenum and titanium dioxide is similar to the anodic behavior of cobalt coatings, except for the potential values of the critical points of the polarization dependences; the values of corrosion current of molybdenum sludges and composite coatings are much lower than cobalt. The sixth section offers maps of technological processes of deposition of Co-Mo and Co-Mo-TiO₂ coatings with indication of basic and auxiliary operations, electrolyte compositions, processing modes.
Смирнова, Олександра Юріївна. "Удосконалення технології формування оксидних шарів на сплаві титану ОТ4–0." Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21923.
Full textThesis for granting the Degree of Candidate of Technical sciences in speciality 05.17.03 – Technical Electrochemistry. – National Technical University "Kharkiv Politechnical Institute", 2016. The thesis is dedicated to improvement of titanium alloy ОТ4–0 oxidizing technology for the creation of materials with anticorrosive and catalytic properties. The electrolytes composition and oxidation mode influence on the oxide coating composition, morphology and properties was established. The technology of titanium alloy ОТ4–0 microarc oxidation, the oxide composition Ti/TiOx∙CeOy, Ti/TiOx∙CeOy∙ZrOz, Ti/TiOx∙CeOy∙ZrOz∙CuOn synthesis was developed. The cerium-containing oxide layers show high catalytic activity in oxidation benzene and monoxide carbon; insertion cuprum and zirconium ions in cerium-containing oxide layers decrease monoxide carbon conversion temperature experimentally established. The electrolytes composition for zirconium- and molybdenum-containing thermostable oxide coatings synthesis is proposed. The synthesized materials corrosion resistance and catalytic activity in the model reaction of carbon monoxide conversion were determined.
Смирнова, Олександра Юріївна. "Удосконалення технології формування оксидних шарів на сплаві титану ОТ4–0." Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21915.
Full textThesis for granting the Degree of Candidate of Technical sciences in speciality 05.17.03 – Technical Electrochemistry. – National Technical University "Kharkiv Politechnical Institute", 2016. The thesis is dedicated to improvement of titanium alloy ОТ4–0 oxidizing technology for the creation of materials with anticorrosive and catalytic properties. The electrolytes composition and oxidation mode influence on the oxide coating composition, morphology and properties was established. The technology of titanium alloy ОТ4–0 microarc oxidation, the oxide composition Ti/TiOx∙CeOy, Ti/TiOx∙CeOy∙ZrOz, Ti/TiOx∙CeOy∙ZrOz∙CuOn synthesis was developed. The cerium-containing oxide layers show high catalytic activity in oxidation benzene and monoxide carbon; insertion cuprum and zirconium ions in cerium-containing oxide layers decrease monoxide carbon conversion temperature experimentally established. The electrolytes composition for zirconium- and molybdenum-containing thermostable oxide coatings synthesis is proposed. The synthesized materials corrosion resistance and catalytic activity in the model reaction of carbon monoxide conversion were determined.