Materials Science and Engineering Commons^™

Study Of Electrodepositing Bright Tin Cobalt Zinc Alloy From Weak Acid Solution, Zhengzhong Zuo, Runxiang Hou, Shaochun Xia

Journal of Electrochemistry

A new process of electrodeposting bright Tin Cobalt Zinc alloy from weak acid solution is proposed in this paper. The solution compositions and operating conditions are Na₃C₆H₅O₇·2H₂O 100～150, Na₂EDTA·2H₂O 20～30, SnCl₂·2H₂O 15～20, CoSO₄·72H₂O 25～35, ZnCl₂ 15～20 g·L^-1; stabilizer WDZ-160～100, brightener WDZ-215～20 mL·L^-1; pH=4～6, D_K=0.5～5.0 A·dm^-2, T=5～35 ℃. A bright Sn-Co-Zn deposit having Co about 0.5～3.5% and Zn about 1～10% is produced. The effects of bath compositions on Co or …

Electroluminescence Of Photoelectrochemically Etched N+-Si, Guozheng Li, Chengqian Zhang, Xiumei Yang

Journal of Electrochemistry

Porous silicon with micrometer size pores, which is made on n⁺-Si by photoelectrochemically etched, has electroluminescent property. Each monochromic intensity and wavelength range of luminescent spectra depend on polarized potential. The intersity and the stability of cathodic electroluminescence is high than those of anodic one. Voltammetric behavior before quenching indicated that the electrochemical reactions of some surface species are involved in except the reduction of S₂O₈^2-, which leads to radiative recombination. The energy band diagram based on n⁺-Si(E_g=1.1 eV)/PS(E_g=1.8 eV) junction is proposed.

Effects Of Curvature On The Electrochemical Behaviors Of Tubular Electrode, Yirong Wu, Zhenghao Wang

Journal of Electrochemistry

The convective diffusion equation of tubular electrode was solved with the implicit finite difference numerical method. Comparing with the electrochemical behaviors of channel electrode, the behaviors of tubular electrode were analysised. The effects of curvature on the electrochemical behaviors of tubular electrode and the limit of applying Levich approximation to tubular electrode were discussed.

Mechanism And Texture Of Ni-Mo Alloy Electrodeposition, Ling Huang, Shukai Xu, Jaoning Tang, Fangzu Yang, Shaomin Zhou

Journal of Electrochemistry

Ni-Mo alloy deposits with (111) preferred orientation was obtained in a solution of 0.22 mol/L NiSO₄·6H₂O, 0.06 mol/L Na₂MoO₄·2H₂O and 0.3 mol/L Na₃C₆H₅O₇·2H₂O in temperature from 25℃ to 50℃, and current densities ranged from 10 mA·cm^-2 to 30 mA·cm^-2. The electrodeposition of Ni-Mo alloy was studied by cylic voltammetry and potential step experiment. It was shown that Ni-Mo alloy is formed by mechanism involving progressive nucleation followed by three dimensional growth of the metal centres. The complex …

Study On The Preparation, Properties And Applications Of The Polymer/Graphite Composite Electrode, Guohua Chen, Jinrui Xu

Journal of Electrochemistry

The graphite AS composite electrodes, which show high electric conductivity, high mechanical strength and operationl stability, were prepared by filling and extruding the AS copolymer with graphite powder. It exhibited a substantial hydrogen overvoltage and small residual current in different electrolytes, as compared with glassy carbon electrode. The electrode was applied to the determination of traces of Pb²⁺ in mineral water, Ag⁺ in waste water and In³⁺, Cu²⁺, Pb²⁺, Cd²⁺ in zinc ore, and showed high stability, reproducibility and selectivity. Owing to the existence of abundant polar functioal groups on the …

The Structure And Electrical Properties Of Srce0.95yb0.05o3 Thin Film Protonic Conductors, Igor Kosacki, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

The results of a study of the structure and electrical properties of SrCe0.95Yb0.05O3 thin film protonic conductors are presented. Dense SrCe0.95Yb0.05O3 thin films (∼1000 nm) with grain size in the 30-70 nm range were obtained on Si- and Al2O3-substrates using a polymeric precursor spin coating technique. The electrical conductivity of these thin films has been studied as a function of temperature and correlated with the microstructure. The thin films showed higher electrical conductivity than dense sintered polycrystalline SrCe0.95Yb0.05O3 specimens which had grain size in the micrometer range. This electrical conductivity enhancement has been attributed to the influence of interfacial grain …

Spin Dynamics Of Er3+ In Erba2cu3o7−Δ, S. Skanthkumar, J. W. Lynn, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Neutron scattering techniques are used to study the magnetic excitations of the Er ions in superconducting ErBa₂Cu₃O₇, a system where the Er ions order antiferromagnetically at TN=0.62 K and the sublattice magnetization obeys the relation for a 2D S=1/2 Ising model. Our data, which were taken on a cold neutron triple axis spectrometer using a horizontally focusing analyzer, reveal that there is a large gap of about 0.20 meV in the excitation spectrum, about four times the thermal energy kTN, as expected for an Ising system. However, we also observe dispersion of the spin …

Spin Dynamics Of Er3+ In Erba2cu3o7−Δ, Suntharalingam Skanthakumar, Jeffrey W. Lynn, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Neutron scattering techniques are used to study the magnetic excitations of the Er ions in superconducting ErBa₂Cu₃O₇, a system where the Er ions order antiferromagnetically at T_N=0.62 K and the sublattice magnetization obeys the relation for a 2D S=1/2 Ising model. Our data, which were taken on a cold neutron triple axis spectrometer using a horizontally focusing analyzer, reveal that there is a large gap of about 0.20 meV in the excitation spectrum, about four times the thermal energy kT_N, as expected for an Ising system. However, we also observe …

An Experimental Investigation Of Bolt Preload Relaxation In Pultruded Gfrp Composite Joints, Srinivas Ravi

Mechanical & Aerospace Engineering Theses & Dissertations

Mechanically fastened joints in pultruded composites are necessary for reasons of maintenance, repair, and assembly. Pultruded composites utilize polymers as matrices and therefore are susceptible to time-dependent effects. The positive effects of increasing the clamping force in bolted joints are well known. To maintain a safe operation of the assembly a minimum clamping force must be guaranteed. But since these materials show time-dependent effects, the bolt-preload relaxes over a period of time. The present study is aimed at investigating the bolt preload relaxation. In this study 1/2 in. thick pultruded sheets were first tested under compression in the thickness direction. …

Development Of A Method For Determining The Relative Manufacturing Complexity Of Advanced Engineering Materials, Shardul Y. Pandya

Engineering Management & Systems Engineering Theses & Dissertations

The immediate adaptation of newly developed materials--with unique and highly desirable properties--is hampered by several factors, including: (1) high material cost and limited availability, (2) lack of information on them, including prior experience in their design and manufacture, immature manufacturing processes and general uncertainty in their behavior patterns, (3) unique handling issues, such as excessive manual labor, high process temperatures, toxicity, disposal problems, limited working lives, and low damage tolerance

Therefore, in spite of their significant benefits, potential users tend to shy away from the widespread use of new materials, instead preferring conventional and tested materials forms.

This dissertation is …

Electrochemical Synthesis And Characterization Of Ba-Pb-O And Bi-Pb-O Oxides, Min Xie, Liangzhong Zhao, Cuiying Xu, Jinbiao Zhang

Journal of Electrochemistry

Pb-based oxides Ba-Pb-O and Bi-Pb-O were synthesized from aqueous solutions by using electrochemical method. The resulting Ba-Pb-O and Bi-Pb-O were characterized using XPS, EDX and XRD. The results show that perovskite BaPb_0.9O₃ can be electrodeposited on the anode only from strong alkaline solution. In acid aqueous solution, conducting BiPb₂O_z oxide is fromed on the anode. In these oxides the nominal valence of lead is +4.

Electrochemical Studies Of Spinel Limn2O4 Rechargeable Lithium Battery, Li Feng, Yuqin Chang, Lie Wu, Hong Li, Yibin San, Tianhong Lu

Journal of Electrochemistry

The spinel Li intercalation compound LiMn₂O₄ was prepared and studied using ac impedance and cyclic voltammogram techniques. It was first discussed that the impedance behaviors of LiMn₂O₄ electrode varied as lithium ion was intercalated in or out the electrode with the help of fractal theory. The Li reversible behaviors in LiMn₂O₄ electrode were shown by the cyclic voltammogram results.

Problems Of The Study Of Anodic Films On Pb In Sulfuric Acid Solution (Ⅲ), Houtian Liu, Qunzhou Wang, Weifang Zhou, Wenbin Cai

Journal of Electrochemistry

The interstitial liquid among the particles in anodic Pb(Ⅱ) films could be the major passage for ion transportation. This is discussed with the mechanism of the cathodic reduction of anodic PbSO₄ film and the effect of Sb on the growth of anodic Pb(Ⅱ) oxides film.

Study On Properties Of Magnesium Alloy Electrode With Anodized Film, Yi Chi, Ping Yang, Xiufeng Lin

Journal of Electrochemistry

The corrosion resistance of Mg alloy electrode with anodized film in atmosphere is bigger than that of the Mg alloy electrode with chromate film. The corrosion resisance and voltage delay of such electrode with anodized film in NaCl solution changed with anodizing comdition. The effects of composition, morphology and thickness of the anodized film on the peoperty of Mg alloy electrode are discussed.

Surface Modifications Of Carbon Materials Used As Anode Of Lithium Ion Battery Ⅱ. The Carbon Material With Core Shell Structure And Its Positive Effect On Cell Performance Of Graphite Anode, Shuhua Ma, Hanju Guo, Ji Li, Hongze Liang, Xiabin Jing, Fosong Wang

Journal of Electrochemistry

The carbon powders and film electrode with core shell structure were prepared by carbonization in gas state with using refined coal as shell material and Artificial Graphite and Mesocarbon Microbeads (2 800 ℃) graphite as core material. Galvanostatic charge/discharge measurement showed that both steady charge/discharge capacity and first charge/discharge efficiency were improved. Cyclic voltammetry indicated that the peak at about 0.7 V vs. Li⁺/Li characteristic of decomposition of electrolyte got weakened, and a more compact film was formed. X-ray diffraction measurement suggested the existence of amorphous carbon shell on the carbon powders and carbon film.

A Study On The Electrodeposition Of Palladium And It's Nucleation, Fangzu Yang, Shukai Xu, Shibing Yao, Bingyi Chen, Xueqing Zheng, Xiaohui Zhong, Shaomin Zhou

Journal of Electrochemistry

The electrodeposition and nucleation of palladium are studied in the system of potassium citrate and ammonium oxalate. The results show that, with the additives of XP-4 and XP-7 prepared in our laboratory, a full bright palladium electrodeposits will be obtained in the wide ranges of the cathode current densities 0.5～3.5 A/dm² and temperature 40～60 ℃; the qualities of the thick deposits will be effectively improved by means of pulse current plating. Cyclic voltammograms results show that the division of peaks between anodic and cathodic on the electrode process of palladium will be up to 1.05 V, which shows the …

Studies On An Iron Heteropolyacid Redox Flow Battery, Peiju Sun, Wansheng You, Zhorgyin Tan

Journal of Electrochemistry

This paper reports a new Fe-HP redox flow cell. The positive and negative electrodes active materials are phosphomolybdic acid and acidified ferrous sulphate solutions respectively. Two activated porous carbon felt electrodes where the electrochemical reactions take place, are separated by a selective cation exchange membrane. The both couples have a suitable electrochemical reversibility on carbon and graphite electrodes. The active materials of the cell have very high stability. Moreover the cell has no life cycle limiting.

Electrochemical Behaviors Of Isoalloxazine Confined In Montomorillonite Olay Modified Electrode, Zhibin Wu, Yuan Lin, Daodao Zhang, Haoqin Wu

Journal of Electrochemistry

A cyclic voltametric investigation of stability and redox properties of isoalloxazne on cetytrimethyammonium bromide (CTAB) modified montomorillonite clay platinium electrode in aqueous solution has been performed. pH dependent film concentrations and apparent diffusion coefficents were measured. The mechanism of the charge transport process with in the clay film were discussed.

Studies On The Cathodic Current Efficiency In The Electrodeposition Ni-Psz Gradient Coating, Jun Li, Dianlong Wang, Li Chen, Xinguo Hu

Journal of Electrochemistry

The cathodic current efficiency and the electrochemical behavior in electrodeposition Ni-PSZ gradient coating were investigated by various electrochemical techniques and scanning electron microscope. The results showed that the Ni-PSZ composite coatings can accelerate evolution of hydrogen with the increase of PSZ content. The overpotential of nickel reduction will be increased and that of hydrogen reaction will be reduced in the presence of PSZ particles in electrolyte. The effect of PSZ particles on nickel electrodeposition was preferentially to catalyze the formation of H ads . These all contributed to the lower current efficiency.

Optical Spray Paint Optimization System And Method, Richard J. Klein Ii, Douglas L. Sevey, Alireza Badakhshan, Ricky J. Bauer

Patents (University of Northern Iowa)

An optical spray paint optimization system can be removably mounted to a spray paint gun, thus enhancing the ability of the user to guide the direction of the spray and also locate the nozzle at an optimum spray distance from the surface being painted. The preferred apparatus uses a diode laser, a beam splitter and a reflecting mirror to generate a reference beam and a gauge beam. The reference beam propagates in a fixed forward direction, but the direction of the gauge beam is adjustable by adjusting the attitude of the reflecting mirror. The reference beam and the gauge beam …

Synthesis And Characterization Of Hafnium Carbide Thin Films, Wiriya Thongruang

Theses

Hafnium carbide thin films of various characteristics were deposited on silicon substrates using dc magnetron sputtering. A HfC target was used as a sputtering source and Ar was used as a sputtering gas during deposition. The variables investigated were total sputtering gas pressure and power. Optimum characteristics were achieved with a total sputtering gas pressure of 5 mTorr and power of 200 W. No evidence for oxidation of the film was found at a depth below 400A for deposited and annealed films. Binding characteristics were obtained from ESCA data. The compressive film stress increased when sputtering gas pressure decreased. The …

Relaxation And The Nature Of Electrical Stress Related Defects In Ultra-Thin Dioxide On Silicon, Lihui Xie

Theses

The instability of defects created in ultra-thin insulator, metal-oxide-silicon devices biased in the direct tunnel regime is investigated. For the case of electron injection from the silicon substrate, nearly complete defect relaxation is observed after the bias is removed, allowing the possibility of re-generating the defects. Modeling the defect generation process and examining differences between initial and subsequent degradation periods lead to an improved picture of both the relaxation process and the nature of the involved defects.

Withdrawal Strength Of Ring-Shank Nails Embedded In Southern Pine Lumber, M J. Skulteti, D A. Bender, S G. Winistorfer, David Pollock

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Ring-shank nails are used extensively in post-frame construction due to their superior performance, yet surprisingly little testing has been done on nail sizes above 12d. Experience in the post-frame industry suggests that published allowable design values for ring-shank nails may be overly conservative and need revision. The goal of the research reported herein was to characterize the withdrawal strength of ring-shank nails embedded in Southern Pine lumber. Three sizes ofgalvanized and ungalvanized (bright) ring-shank nails from two manufacturers were studied. Ring-shank nails had approximately twice the withdrawal resistance of smooth-shank nails of the same diameter. Galvanizing slightly reduced withdrawal strength …

Thin Film Deposition Of Silicon For Solar Cell Applications, Sailesh Kumar, Roger M. Hawk

Journal of the Arkansas Academy of Science

Thin films of silicon have been formed using a patented electrostatic deposition method which utilizes charged particle motion in an electric field. After deposition, the films are heat treated for varying times and temperatures in a programmable furnace maintained under a purified argon atmosphere. X-ray diffraction (XRD) confirmed that these films were polycrystalline in nature. These films were found to have grain sizes of about 50 microns. Solar cells were fabricated using these large grained polycrystalline silicon films by sputtering pure gold as both front and back contacts. The cells have shown efficiencies of 1.8%. This paper reports on the …

The Effects Of Machining On Structure And Tribological Properties Of Ultra High Molecular Weight Polyethylene For Artificial Joint Prostheses, Jinshan Song

Masters Theses

Understanding the effect of machining on the structure and property of subsurface layer of ultra high molecular weight polyethylene (UHMWPE) can significantly facilitate the increase in longevity of artificial joints. This study was performed to investigate the machining effects on the polymeric structure and tribological properties. Machining parameters include cutting speed, tool feed rate and depth of cut. Temperature rise was studied during machining to assess the extent of thermal degradation due to machining. Polymeric structure of the semicrystalline polymer was characterized using differential scanning calorimetry (DSC) in terms of melting enthalpy, crystallinity and melting temperature. Surface texture and hardness …

Investigation Of The Optical Properties Of Ordered Semiconductor Materials, Jack E. Mccrae Jr.

Theses and Dissertations

Optical studies have been conducted upon CdGeAs₂ and ZnGeP₂, two of the most promising semiconductors being developed for mid-infrared non-linear optics applications. These experiments included photoluminescence (PL) studies of both compounds as well as photoreflectance (PR) measurements upon CdGeAs₂. In addition, Hall effect measurements were carried out upon CdGeAs₂, to aid in interpretation of the optical data. PL was measured as a function of laser power, sample temperature, and crystal orientation for CdGeAs₂. One broad weak peak near 0.38 eV, and another somewhat narrower and often far brighter peak near 0.57 …

The Effect Of Casting Shape And Size On Solidification Time: A New Approach, Murat Tiryakioǧlu, Ergin Tiryakioǧlu, Donald R. Askeland

Materials Science and Engineering Faculty Research & Creative Works

The limitations of Chvorinov's Rule for predicting the solidification time of a casting are discussed and previous studies intended to modify Chvorinov's Rule in order to express the effect of the size and shape of castings on solidification time are reviewed. A new model that introduces a shape factor is presented that predicts the solidification times of castings as well as or better than Chvorinov's Rule, particularly for more complex shapes. The validity of the new model is compared with the conventional Chvorinov's Rule by a statistical analysis of twelve sets of data obtained from the literature.

Preparation Of Powder Precursors And Evaporation Of Photoconductive Indium Sulfide Films, Chris Barber, Robert Engelken, Brandon Kemp, Wasim Aleem, Imran Khan, Chris Edrington, Michael Buck, Clayton Workman, Anup Thapa, Tom Jakobs

Journal of the Arkansas Academy of Science

We have demonstrated significant photoconductance in indium sulfide thin films prepared by thermal vacuum evaporation ofIn2$3 powders synthesized in-house by chemical precipitation ofInCl3 or In(CH3COO)3, and (NH4)2S or Na2S. The Delta G lambda/Gdark values have been as high as 0.1 in the initial unoptimized films. Excess sulfur (via a mixture of polysulfide and sulfide ions in the synthesis bath) appears to be important in achieving reproducible and large photoconductivities. In2S3 is particularly attractive as a lower toxicity alternative to CdS in optoelectronic applications such as photovoltaic and photoconductive cells.

Evaluation Of Unified Interaction Parameter Model Parameters For Calculating Activities Of Ferromanganese Alloys: Mn-Fe-C, Mn-Fe-Si, Mn-C-Si, And Mn-Fe-C-Si Systems, L. I. Hongjie, Arthur E. Morris

Materials Science and Engineering Faculty Research & Creative Works

Interaction parameters for Mn-based alloys were evaluated using both carbon solubility and activity data for species in binary and ternary manganese alloys. The parameters at 1400 °C are the following εcc = -4.5; εccc = 58.8; εFeCC = 1.5; εFeCC = 2.5; In γC0 = -1.15 . εsisi = 15.5; εsisisi = 2.69; εFeSi = 2.5; εcsi = 12.4; εccsi = 27.5; In γSi0 = -7.46 The unified interaction parameter model (UIPM) was used to calculate the activity coefficients of species and the solubility of carbon in ferromanganese alloys (up to quaternary Mn-Fe-C-Si). The results were in good agreement with …

Mechanical And Tribological Properties Of Composites Of Recycled High Density Polyethylene And Recycled Rubber, Jason G. Boulanger

Masters Theses

This thesis presents a study on the mechanical and tribological properties of composite materials of recycled high density polyethylene (HDPE) and recycled rubber tire particles. The materials were compounded by extrusion and formed into test specimens by injection molding.

The first experiment studied the effect of recycled rubber percentage on mechanical properties of composites of recycled HDPE and recycled rubber. The mechanical properties included tensile strength, percent elongation, hardness, and impact resistance. Recycled rubber concentrations of 0, 5, 10, 15, 20, 25, and 30 percent were tested. The second experiment investigated the tribological properties of recycled HDPE and recycled rubber …