Master of Science, The Ohio State University, 2014, Mechanical Engineering

Nickel-titanium is a shape memory alloy capable of producing high stresses with an 8% maximum recoverable strain. The rotation of a nickel-titanium (NiTi) torque tube can be controlled by thermally cycling the material through its critical martensite and austenite temperatures. Transforming the phase of NiTi corresponds to a change in its crystalline structure and a macroscopic change in shape. This change in shape, through a controlled thermal input, lends itself well to powering a solid-state actuator. Shape memory alloys can in some cases replace traditional actuators, for instance in harsh aerospace environments where lightweight operation is critical. NiTi is effective as a solid-state actuator, but it is very difficult to machine. The poor machinability of NiTi drives the cost and complexity of system integration to the point where its widespread use is hindered. The general solution is to join NiTi to a structural material and machine the structural material for system integration. Several types of joining methods have been studied such as ultrasonic soldering, adhesives, and laser welding. This study focuses on tungsten inert gas (TIG) welded joints between 304 stainless steel and NiTi tubing. A nickel filler is used in TIG welding of NiTi to 304SS to prevent brittle intermetallics formed by titanium and iron in the weld pool. The thickness of the nickel filler and the current required to create a strong TIG weld in torsion failure is investigated in a Taguchi L9 full factorial test matrix. Based on ultimate failure torque test results and welding observations, a 0.050'' filler thickness with an 85 A starting current was chosen for thermocycling tests with a constant load. The chosen joint parameters produce an average ultimate failure torque of 371 in-lb (41.9 N-m) with a shear strength of 41 ksi (282 MPa). EDS analysis of 0.025'' and 0.075'' filler thickness welds confirm observations from welding and test data with a crack caused by TiFe intermetal (open full item for complete abstract)

Committee: Marcelo Dapino Dr. (Advisor); Mark Walter Dr. (Committee Member) Subjects: Mechanical Engineering

Doctor of Philosophy (PhD), Ohio University, 2013, Chemistry (Arts and Sciences)

A series of new environmentally and catalytically significant bioinorganic redox active pseudotetrahedral Ni(II) thiolate and Ni(II) phenolate (S=1, d8) complexes were synthesized and fully characterized as small molecular models in order to study the coordination mode of the Ni-S bond that is biologically significant in anaerobic and archaebacterial enzymes. During this characterization a unique Ni-S ligation mode was discovered and modulated by steric titration and details were further investigated. Nickel thiolate bond reactivity towards electrophilic alkylation with methyl iodide (MeI) is briefly discussed. A series of new Ni(II) phenolate complexes were synthesized and characterized as well as their O2 activation activity were investigated as a model for nickel substituted Copper Amine Oxidase (CAO). During this O2 reduction investigation, depending on the ligand bulk on the parent TpPh,Me/TpMe,Me ligand (where, TpPh,Me= hydrotris{3-phenyl-5-methyl pyrazol-1-yl}borate; TpMe,Me= hydrotris{3,5-dimethyl pyrazol-1-yl}borate) either a C-H or a C=C bond activation was observed. In addition, surprisingly where C-H activation was not possible, a CO2 capture activity was observed by a reactive intermediate nickel species.

Committee: Micahel Jensen PhD (Committee Chair); Jeffrey Rack PhD (Committee Co-Chair); Hugh Richardson PhD (Committee Member); Alexander Govorov PhD (Committee Member) Subjects: Biochemistry; Chemistry; Inorganic Chemistry; Organic Chemistry

Doctor of Philosophy (PhD), Wright State University, 2008, Engineering PhD

Fretting wear is an accumulation of damage that occurs at component interfaces that are subjected to high contact stresses coupled with low amplitude oscillation. The key to fretting wear reduction in metallic contacts is the mitigation of galling at the interface, followed by the control of debris production and the rheology of active wear debris. Once the thin surface species of the metallic interfaces is dispersed, adhesion between the contacting nascent surfaces causes the inception of severe surface deformation and material transfer or removal. This is extremely apparent in the fretting wear of aerospace materials such as titanium alloy and nickel alloy contacts. However, the literature suggests that nickel alloy contacts perform very well in sliding and reciprocating wear contacts at elevated temperatures due to the formation of what is often called a Glaze oxide layer. The current state of literature describes the composition of the glaze layer as NiO. The focus of this dissertation was to provide experimentation and analysis of temperature effects on the lubricious tribofilm formation that occurs in nickel contacts. This was accomplished by testing commercially pure nickel coatings and thick nickel oxide surfaces. The enhanced understanding of the fretting performance of nickel oxides aided in the development of nickel graphite based self-lubricating coatings. These coatings were then proved to reduce fretting wear damage within Ti6Al4V mated surfaces over a wide temperature range.

Committee: Ramana Grandhi PhD (Advisor); Terry Murray PhD (Committee Member); Joseph Slater PhD (Committee Member); Jeffrey Sanders PhD (Committee Member); Andrey Voevodin PhD (Committee Member); Daniel Young PhD (Committee Member) Subjects: Engineering; Experiments; Materials Science

Master of Science, The Ohio State University, 2005, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2008, Graduate School

Committee: Not Provided (Other) Subjects:

Doctor of Philosophy, The Ohio State University, 2022, Chemistry

The utilization of enzymes as bioelectrocatalysts is of increasing interest due to their advantages in chemical specificity and catalytic rates. Emphasis has been placed on hydrogen producing biocatalysts to overcome drawbacks of current heterogeneous catalysts, including limited availability and poor selectivity. Native enzymes, such as the [NiFe] hydrogenase, have demonstrated extreme proficiency as bi-directional catalysts for proton reduction and hydrogen oxidation, inspiring a variety of small molecule and protein mimics. The utilization of a robust and stable protein scaffold with a similar primary coordination environment as the native enzyme can result in similar activity. Previous reports have demonstrated that nickel-substituted rubredoxin (NiRd) serves as a structural, functional and mechanistic model of the [NiFe] hydrogenase, active towards proton reduction electrochemically and in solution, with an identical primary coordination sphere at the nickel center as the native enzyme. While the mechanism of proton reduction has been experimentally and computationally modeled to be similar to that of the native enzyme, key catalytic intermediates have not yet been isolated and characterized. This project aims to address some of the limitations of this current model, such as significant overpotential and lack of spectroscopic characterization of catalytically competent intermediates. Further, correlation between redox activity and protein structure are investigated by modification of the protein primary sphere coordination site. Primary sphere mutants demonstrate changes in the redox and catalytic behavior dependent on the cysteine site being modified. Drastic changes to the primary coordination sphere are explored using electrochemistry along with optical, multiwavelength resonance Raman, X-ray and electron paramagnetic resonance spectroscopies. This study demonstrates the ability to keep and shut off catalysis, aiding in the understanding of enzyme selectivit (open full item for complete abstract)

Committee: Hannah Shafaat (Advisor); Yiying Wu (Committee Member); Shiyu Zhang (Committee Member); Anne Co (Committee Member) Subjects: Chemistry

Doctor of Philosophy, University of Toledo, 2020, Chemistry

Transition-metal-catalyzed hydroelementation is one of the most important methods for the synthesis of functionalized molecules. Hydroboration and hydrosilylation are two important classes of hydroelementation reactions. In chapter 1, the applications of these transformations, recent catalyst development, and the operating mechanisms are briefly discussed. The challenges and scope in base-metal catalysis for hydroboration and hydrosilylation are also described. In chapter 2, the selective hydroboration of aldehydes and N-allylimines utilizing a well-defined cationic nickel complex is described. The catalyst displayed excellent selectivity toward aldehydes in the presence of ketones. A wide variety of functional groups were tolerated, including halogens, nitro, cyano, and alkenes for both aldehydes and imines. Electron-rich substrates were found to be significantly more reactive than their electron poor counterparts, a unique feature, reported for the first time in metal-catalyzed hydroboration. Stoichiometric reactions with the catalyst disclosed that the substates were activated through a Lewis acidic interaction and undergo hydroboration with pinacolborane (HBpin) under mild reaction conditions. In chapter 3, seven structurally similar cationic nickel(II)−alkyl complexes were synthesized by using a series of P, N ligands, following the previously developed protocol from our lab and their reactivity was explored in the hydrosilylation of alkenes. Newly synthesized catalysts were characterized by NMR spectroscopy, elemental analysis, and X-ray crystallography. The study showed that more electron-rich phosphines enhanced the overall reactivity of the hydrosilylation; in contrast, groups on the imine donor had little impact. Overall, these catalysts displayed reactivity and selectivity that was previously unknown or very rare in nickel-catalyzed hydrosilylation. In reactions with Ph2SiH2, 1,2-disubstituted vinylarenes showed complete benzylic selectivity for sil (open full item for complete abstract)

Committee: Joseph A. R. Schmidt (Committee Chair); Mark R. Mason (Committee Member); Wei Li (Committee Member); L.M. Viranga Tillekeratne (Committee Member) Subjects: Chemistry; Inorganic Chemistry; Organic Chemistry

PhD, University of Cincinnati, 2017, Arts and Sciences: Chemistry

The development of new catalysts for the reduction of carbon dioxide is of utmost importance to both limit the harmful greenhouse gas as well as to provide usable C1 feedstock chemicals. One method to reduce this CO2 is through the use of a metal hydride complex. Of these metal complexes, nickel POCOP pincer hydride complexes have been highly successful at catalyzing the reduction of carbonyl functionalities. Although these catalysts are effective at catalyzing this reduction, there are few processes to make these hydrides. Additionally, not much is known about which factors will improve catalytic reduction or what other reactions they can catalyze. Nickel chloride complexes bearing POCOP pincer ligands were easily synthesized using a microwave reactor. Through this methodology nickel POCOP pincer chloride complexes can be made in as little as 5 minutes in very high purities and yields. Nickel complexes with iPr, cPe, Cy, Ph, and tBu substituents on the phosphorous atoms can all be synthesized using this method. Additionally, palladium chloride complexes bearing isopropyl substituted POCOP ligands can be made. This method was also found to greatly limit the solvent needed to make these complexes. Alternative routes to synthesize nickel hydride complexes is an important problem due to the harsh methods used to synthesize them. To explore an additional method for hydride synthesis, nickel fluoride complexes bearing POCOP pincer ligands were synthesized. These complexes can be easily converted to hydride complexes using silanes or boranes. The factors that influence a metal hydrides ability to reduce CO2 were investigated. To determine which factors had an impact on the reduction of CO2 to formate complex, a series of nickel hydride and formate complexes were synthesized. The complexes were tested to determine the relative thermodynamic favorability for the reduction of CO2 to formate. Complexes bearing more electron donating ligands were found to be (open full item for complete abstract)

Committee: Hairong Guan Ph.D. (Committee Chair); William Connick Ph.D. (Committee Member); Allan Pinhas Ph.D. (Committee Member) Subjects: Chemistry

Doctor of Philosophy, The Ohio State University, 1985, Graduate School

Committee: Not Provided (Other) Subjects: Engineering

Doctor of Philosophy, The Ohio State University, 1971, Graduate School

Committee: Not Provided (Other) Subjects: Chemistry

PhD, University of Cincinnati, 2012, Engineering and Applied Science: Materials Science

Thin films in the (Ni/NiO) system have been widely studied because of their significant potential for use in batteries, fuel cells, solar cells, supercapacitors, magnetic devices and various sensor applications. Such films typically are deposited onto suitable substrates by electrochemical or vapor deposition methods, followed by heat treatment to develop the oxide structure. In this study, by contrast, the Ni/NiO thin films were prepared by metallo-organic decomposition (MOD) technique in order to facilitate the development of nano structure feature as well as molecular scale mixing and excellent composition control. Critical parameters that must be controlled during this deposition process to achieve high quality films include: carboxylate precursor chemistry, solution chemistry, film structure chemistry, film deposition characteristics, film structure development and pyrolysis characteristics. These crucial control parameters are, for the most areas, poorly understood for this system especially for the carboxylate precursor chemistry effects on properties of Ni/NiO thin films. The goal of this work, therefore, is to understand and design those parameters in term of precursor species, viscosity, solute concentration and solvent composition as well as film deposition and heat treatment conditions that can lead to the controlled fabrication of nano-sized, high surface area, low resistive Ni/NiO thin films on Si and metallic substrates such as stainless steels and silver. The solvent system used consisted of a unique mixture of propionic acid and amylamine, in molar ratio of 0.5-2.0, with Ni acetate as the solute precursor in the concentration range of 0.2-2 mol/l. The films were prepared by spin deposition at 3000 rpm from carboxylate solution precursors with viscosity range of 10-640 cP. Good quality nano-sized Ni/NiO thin films, in the range of 0.2-2 µm thickness, on Si or stainless steel substrates were obtained by a mixed AA/PPA solvent system in the molar rati (open full item for complete abstract)

Committee: Relva Buchanan ScD (Committee Chair); Stephen Clarson PhD (Committee Member); Rodney Roseman PhD (Committee Member); William Vanooij PhD (Committee Member) Subjects: Materials Science

Doctor of Philosophy, The Ohio State University, 2007, Materials Science and Engineering

Micron-sized compression specimens, fabricated using a focused ion beam (FIB), indicate a dramatic strengthening effect as sample dimensions are reduced from 20μm to sub-micron diameters in nickel and gold microcrystals. To understand this effect, novel microscopy techniques were utilized to study the mechanical properties and dislocation substructures from microcrystals of pure nickel, Ti-6wt.%Al, Ti-6Al-2Sn-4Zr-2Mo-0.1Si (Ti-6242) and Ti-50.8at.%Ni. The dislocation behavior that governs plasticity is quite different between each of these materials and as such produces different size effects at small sizes. The nickel compression results indicate a dramatic increase in strength as sample dimensions are reduced. Quantitative dislocation density measurements performed on slip-plane TEM foils extracted from nickel microcrystals indicate an increase in stored dislocation density at smaller sizes. However, hardening contributions from forest-hardening and source truncation hardening were insufficient in explaining the high observed flow stresses. This result suggests that other hardening mechanism are operating in the nickel microcrystals. The titanium alloys exhibit a much less dramatic strengthening effect compared to the nickel microcrystals. The titanium microcrystals, at all sample sizes tested (1-60μm), are stronger than bulk compression specimens. Even at the 60μm sizes bulk behavior is not observed, while at only 20 microns nickel microcrystals exhibit bulk properties. Transmission electron microscopy (TEM) investigations indicate several dislocation pile-ups of both screw and edge character at the microcrystal surfaces. These pile-ups appear to be related to ion damage induced by the fabrication of these samples, resulting in a strengthening effect that follows a Hall-Petch relationship. Nickel-Titanium alloys deform through a phase transformation, as well as dislocation motion. The microcrystal compression results indicate no observable size effect related to (open full item for complete abstract)

Committee: Michael Mills (Advisor) Subjects: Engineering, Materials Science

PHD, Kent State University, 2009, College of Arts and Sciences / Department of Physics

The study of quantum phase transitions (QPT) provides a new route to find and understand unconventional phases in condensed matter physics. The presently studied alloy, Ni(1-x)Vx, offers an opportunity to investigate a ferromagnetic quantum phase transition, a transition from a ferromagnetic ordered state into a paramagnetic state at T = 0 K, by varying the vanadium concentration, x. Magnetization and transport measurements are used to probe the critical behavior of the phase transition and characterize the onset of “unconventional behavior” such as non-Fermi liquid behavior, which signals a deviation from Fermi liquid theory, a fundamental concept in metals. Towards 11.2 % vanadium, the Curie temperature (Tc) is reduced to zero from its pure nickel value of Tc = 627 K. The critical behavior of the phase transition in samples with the higher nickel content (x < 11%) at a finite Tc essentially follows theories as expected for weak itinerant magnets. The samples with more vanadium (x > 11.2%) do not show a conventional ferromagnetic transition or the typical properties of an ordinary paramagnet. Instead, we see evidence for power laws with unusual exponents in the temperature dependence of the magnetization and the resistivity due to an inhomogeneous magnetic moment distribution. We compare our data findings with recent theories addressing a new critical scenario, quantum phase transitions with disorder. One signature is a Quantum Griffiths' phase which is observed as power laws with non-universal exponents heading towards a T → 0 instability. At very low temperatures, the quantum Griffiths phase in Ni-V leads to the formation of a frozen cluster glass phase. To our knowledge, our compound is the first to experimentally show all signatures of a quantum Griffiths phase in an extended regime, and therefore provides an ideal model system for a disordered itinerant 3-d Heisenberg system.

Committee: Almut Schroeder Dr. (Advisor); Carmen Almasan Dr. (Committee Member); David Allender Dr. (Committee Member); Songping Huang Dr. (Committee Member); Robert Twieg Dr. (Committee Member) Subjects: Physics

Doctor of Philosophy, Case Western Reserve University, 2006, Chemical Engineering

Neuroprosthetic devices that electrically stimulate paralyzed muscles require implantable power sources with exceptional cycle life, safety, and sufficient energy and power density. Of the rechargeable battery technologies, lithium ion batteries have the highest energy density; however, they have limited cycle life of about 1000 cycles. Nickel-hydrogen batteries, currently used in space applications are remarkable for long cycle life (40,000) and low maintenance; however they utilize high hydrogen pressures (60 atm) making them unsuitable for implantable applications. The present work involves design and development of low pressure nickel-hydrogen batteries (1 atm) by utilizing a metal hydride (MH) to store hydrogen, rather than as a negative electrode in the nickel-metal hydride battery. A method to increase the exchange current density of the negative platinum electrode using cyclic voltammetry was developed. A nickel mesh was chosen as the current collector because of its low resistance and stability in alkaline solutions. The tested separators, zirconium oxide and polypropylene, were not significantly different from each other. A pasted type nickel hydroxide electrode was fabricated by two means: screen printing and spatula pressing. The mechanism of electrode formation, the effect of different formation rates with and without overcharge and the effect of binder and nickel content on utilization were studied. Addition of filamentary nickel to the electrode increases the utilization by 10% by decreasing the oxygen evolution. A low pressure nickel-hydrogen battery with and without MH was assembled. Charge and pressure data were analyzed to study the oxygen evolution, the recombination reaction and the self discharge of the cell. Oxygen evolution increases with the depth of charge; however the evolved oxygen recombines completely – 70% during charging and the remainder during the first hour of the rest period. About 40-45% hydrogen from the metal hydride was used a (open full item for complete abstract)

Committee: Jesse Wainright (Advisor) Subjects: Energy; Engineering, Chemical

Master of Science, The Ohio State University, 2007, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 1971, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 1969, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2005, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 1966, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 1922, Graduate School

Committee: Not Provided (Other) Subjects: