Percentage Of Cobalt Research Articles

Effect of doping with cobalt on the structure and optical properties of zinc oxide thin films prepared by sol-gel method

In this study, pure zinc oxide films doped with a cobalt percentage of 3% were prepared using Sol-Gel spin coating technique on a glass substrate at a temperature of 100 degrees Celsius. The structural and optical properties of these films have been studied. Structure properties are obtained by using x-ray diffraction (XRD) technique, they were carried out using a device of type (Panalytical X ‘Pert pro) with a target of type (Cu Kα) and a wavelength of (λ = 1.541 Ao). The diagnostic results showed that these films are polycrystalline and have a hexagonal structure with preferential orientation at (101). The Optical properties are concluded from absorption and transmission measurements, which are obtained by using the double beam UV-Visible1800 spectrophotometer in the wavelength (300–800) nm. It was found that the absorbance increases with increasing the doping percentage (1, 2, 3, and 4)mol%, while the transmittance is decreased. The optical properties also included the energy gap, the absorption coefficient, the reflectivity, the refractive index, the extinction coefficient, and the dielectric constant in its real and imaginary parts. It was found that the energy gap values decreased in the range 3.32–3.03 eV and the transmittance rate was 90% within the visible spectrum region.

Investigation of the structural, optical and thermoelectric performances of flash-evaporated cobalt-doped copper sulfide thin films

In this study, we employed the flash evaporation method to deposit thin films of pure copper sulfide and cobalt-doped copper sulfide. We focused on evaluating the influence of cobalt content, ranging from zero to 9%, on the structural, optical, electrical, and thermoelectric characteristics of the synthesized thin films. Our findings indicate that the passage from the copper-rich (covellite phase to the digenite or djurleite phases) can be carried out by annealing or by doping. Raman's investigation supports the discovered phase and shows that the A1g(LO) mode intensity drops with doping. The gap energy was found to decrease by increasing the percentage of cobalt. The annealing at 350 °C resulted in good thermoelectric properties, while the dominance of the djurleite phase, resulted in the highest Seebeck coefficients.

Effect of weak doping with cobalt over the optical magnitudes of tin oxide thin films

This paper aims to investigate the different properties of cobalt-doped and undoped tin oxide thin films. The tin oxide thin films were doped with different atomic percentages of cobalt, ranging from 0% (undoped) to 2% and 4%, using a cost-effective and easily accessible technique known as spray pyrolysis with a moving nozzle at 490 °C. The phase identification of the different thin layers was carried out using X-ray diffraction, which indicated that the compound is homogeneous has a polycrystalline structure and is, with preferential orientation growth at the (211) level. The optical properties of the synthesized thin films were investigated using UV-visible spectroscopy in the range from 300 to 900 nm, which allowed the estimation of both linear and nonlinear optical properties. The results of the investigations into the linear optical properties indicated that the samples have a direct band gap energy between 3.75 to 3.81 eV, permittivity between 2.67 to 3.266, photoelectrons between 0.2 to 3.35 = 1025, and refractive index between 1.778 to 1.875. The results also indicated that the absorption cross section changes with photon energy and the number of photoelectrons, where it has an approximately constant value at low energies. Moreover, the nonlinear optical properties were determined using the Sheik-Bahae model, which revealed that the samples have the same maximum two-photon absorption (TPA) process coefficient of 3.63 cm/W and the same maximum nonlinear refractive index (NRI) value of 6.91 × 10−8 cm2/W.

Comparing the effects of undoped and cobalt doped copper oxide nanoparticles on the enhancement of water thermal conductivity coefficient

In this study, cobalt doped copper oxide nanoparticles (Cu1-xCoxO) for different amounts of cobalt concentrations were fabricated successfully. The fabricated samples were characterized by XRD and SEM. X-ray diffraction patterns confirmed the formation of copper oxide and also the substitution of cobalt atoms in the position of copper atoms in the crystal lattice structure of CuO.After that, water-based nanofluids were fabricated by adding different percentages of cobalt doped copper oxide nanoparticles to pure water. Measurement of the thermal conductivity coefficient (TCC) of fabricated nanofluids showed that the TCCs of samples is increased due to the addition of the (Cu1-xCoxO) nanoparticles. This study showed that doping of copper oxide with cobalt causes more increase in the TCCs of nanofluids, and the rate of this increment linearly depends on the dopant concentration. The TCC dependencies of the nanofluids to the temperature and concentration of nanoparticles were also investigated.

Hollow platinum-gold and palladium-gold nanoparticles: synthesis and characterization of composition-structure relationship

Hollow palladium-gold (PdAu) and platinum-gold (PtAu) alloy nanoparticles (NPs) were synthesized through galvanic replacement reactions. PdAu NPs denoted PdAu-99.99 and PdAu-98 were produced using palladium precursors with different purity degree: Na2PdCl4 ≥ 99.99% and Na2PdCl4 98%, respectively. The effect of the addition time of the gold palladium precursor solution on the size of the generated NPs was evaluated. Two types of particles, with a rough and a smooth surface, were identified in the suspensions of PtAu and PdAu NPs by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM). The atomic percentage of gold, platinum, palladium, and cobalt (atomic %) in the nanoparticles was determined by energy dispersive X-ray spectroscopy (EDX). PtAu NPs (26–42 nm) contain Pt (41 at%), Au (36 at%), and Co (23 at%). Two groups of hollow palladium gold NPs (30–50 nm) with a different residual cobalt content were produced. PdAu-99.99 NPs consisted of Pd (68 at%), Au (26 at%), and Co (6 at%), whereas PdAu-98 NPs were composed of Pd (70 at%), Au (22 at%), and Co (8 at%). The hollow structure of the NPs was confirmed by EDX line scanning. Selected area electron diffraction analysis (SAED) revealed the formation of PtAu and PdAu alloys and it was used in estimating the lattice parameters, too.

Cobalt Biosorption in Fixed-Bed Column Using Greenhouse Crop Residue as Natural Sorbent

Intensive greenhouse agriculture annually produces large amounts of residues. The present work focused on the study of the dynamic adsorption of cobalt from aqueous solutions over a vegetal residue from intensive greenhouse cultivation. The influence of three operating variables, feed-flow rate, inlet concentration of cobalt and bed height, was analyzed. According to the results, the variable that particularly affected the percentage of cobalt adsorbed was the feed-flow rate. The results were also fitted to an adaptive neuro fuzzy system (ANFIS) model to predict cobalt adsorption from aqueous solutions and choose the most favorable operating conditions. Results were evaluated using root mean squared error (RMSE), coefficient of determination (R2) and other typical statistic factors as performance parameters. The experimental and model outputs displayed acceptable result for ANFIS, providing R2 values higher than 0.999 for both cobalt removal (%) and biosorption capacity (mg/g). In addition, the results showed that the best operating conditions to maximize the removal of cobalt were 4 mL/min of feed-flow rate, 25 mg/L of inlet concentration and 11.5 cm of bed-height.

Investigation of Optical, Structural, Morphological and Electrical Properties of Electrodeposited Cobalt Doped Copper Selenide (Cu_(1-x) Co_x Se) Thin Films

Undoped and cobalt doped copper selenide thin films have been successfully prepared unto fluorine tin oxide (FTO) substrates by electrodeposition method using copper acetate, cobalt nitrate and selenium (IV) oxide as precursors for copper, cobalt and selenium ions respectively. Deposited thin films were subjected to optical, structural, morphological, compositional and electrical analysis using spectrophotometer, x-ray diffractometer, scanning electron microscope (SEM), energy dispersive x-ray spectroscopy (EDS) and 4-point probe. Optical results observed between the wavelength range of 300 nm and 1,000 nm showed that the films have good optical responses. Absorbance values ranged between 0.1 and 0.81 while transmittance lies between 15.59 and 78.68 %. Energy band gap of the films was found to vary from 2.10 to 2.28 eV. These results showed that cobalt as a dopant could be used to modify properties of copper selenide thin films. Structural analysis showed that the deposited films are polycrystalline in nature with hexagonal structural phase. Crystallite sizes of range 27.56 to 34.27 nm were obtained while dislocation density lied between and . Microstrain ranged between and . Micrograph images showed flake-like particles that increased in size as percentage of cobalt increased. Energy dispersive spectroscope (EDS) results confirmed the incorporation of cobalt on the deposited copper selenide films. Electrical resistivity of the films increased from to while conductivity decreased from to as a result of variation in cobalt ion concentration. These properties of the deposited thin films positioned them for solar cell and optoelectronics device applications.
 HIGHLIGHTS
 
 Energy band gap of electrosynthesized cobalt doped copper selenide ranged from 2.10 to 2.28 eV
 Film thickness values ranged from 48.41 and 176.79 nm. Thickness values of the films were found to increase as concentration of cobalt increase
 Increase in dopant concentration resulted to shift in diffraction peaks towards larger angles
 Increase in crystallite size from 27.56 - 34.27 nm was observed as dopant concentration increases
 SEM images of the films revealed flake - like particles of different sizes
 
 GRAPHICAL ABSTRACT

Impregnated layer combustion synthesis of co doped ZnO green nanopigments: Using nature-based cellulosic templates

In this research, nanostructured green pigments of ZnO and Co (CoxZn1-xO) were synthesized using impregnated layer combustion synthesis under microwave radiation. Taguchi design of experiments was employed to systematically investigate the influence of variables including the type of fuel, cobalt percentage, fuel to oxidizer ratio and type of template (impregnated active layer) to minimize the average crystallite size of particles. Three different types of fuels such as xylitol, mannitol and sorbitol as well as three templates containing filter paper, cotton and sterile gauze were used for the first time for synthesizing CoxZn1-xO nanopigments. The optimum sample with the average crystallite size of 35 nm was synthesized in specific conditions including mannitol as a fuel, filter paper as a template, cobalt percentage of 7%, fuel to oxidizer ratio of 1.3× stoichiometry. XRD analysis demonstrated that whole samples have followed ZnO pattern representative pure phases in the final structure and well-doped Co2+. FESEM images revealed the homogeneity of the nanoparticles, with average particle size of 90 nm. As a result of colorimetric studies on the optimum sample a broad reflectance band nearby 520 nm demonstrates green region with L* = 58.19, a* = −13.65, C* = 14.35 and h° = 162.07. Results showed that the pigment calcination influences the reflectance intensity effectively (∼40%). Co percentage and template type are the most important factors affecting the final green product colorimetric properties.

Nucleation/Growth and Optical Proprieties of Co-doped ZnO Electrodeposited on ITO Substrate

A Co-doped ZnO layer was prepared by electrodeposition method on indium doped tin oxide (ITO) substrate using a cathodic reduction from nitrate medium with different doping percentages of cobalt. The bath temperature was controlled at 70 °C. The films were cathodically electrodeposited in a bath containing 5 mM Zn(NO3)2. 6H2O, while the source of Co is Co(NO3)2.6H2O where 0.1M KNO3 was used as supporting electrolyte. The nucleation and growth mechanism of Co-doped ZnO nuclei have been studied by cyclic voltammetry and chronoamperometry. The cyclic voltammetry shows that the electrodeposition of ZnO and Co-doped ZnO at a negative potential around -1.0 V versus saturated calomel electrode (SCE) is a quasi-reversible reaction controlled by the diffusion process. Comparing current transients curves obtained by the chronoamperometric method with the theoretical curves of current density j versus t ½ allows us to say that the nucleation is 3D instantaneous, as shown in SEM analysis. The presence of Co does not modify the nucleation and growth mechanism. The XRD patterns show that the substitution of zinc by cobalt does not change the würtzite crystal structure, but the crystallite size decreases with the cobalt percentage. The transmittance spectra indicate that the Co-doped ZnO films are transparent in the visible range. The optical gap increases with the doping percentage of cobalt.

Heat Treatment Effect in the Corrosion Resistance of the Al-Co-Mn Alloys Immersed in 3 M KOH

Al-based alloys named M1, M2, M3, M4, and M5 doped with different atomic percentage (at%) of cobalt and manganese as cast and submitted at two heat treatments (600°C and 1100°C) were analyzed by using electrochemical techniques to evaluate their corrosion resistance immersed in 3 M KOH. With the heat treatments applied to the alloys, the sample M2 (65% Al, 20% Co, and 15% Mn) observed the highest corrosion resistance withRpvalues of3.0×102,6.2×102, and1.61×103 Ω·cm2as cast, 600°C, and 1100°C, respectively. The latter was in agreement with theIcorrcalculated from the polarization curves where the values decrease based on the heat treatment applied as follows:1.60×103>6.16×102>3.07×102 mA/cm2for 1100, 600, and as cast, respectively. Co concentration above 20% increases the corrosion current (Icorr) and decreases the polarization resistance of the remain samples. The chemical analysis done with EDS and X-ray diffraction made confirmed the presence of compounds such as CoAl, Co2Al5, Co2Al9, MnAl4, and MnAl6.

Structural, Morphological, and Magnetic Properties of Nickel Substituted Cobalt Zinc Nanoferrites at Different Sintering Temperature

Co-precipitation was used for the preparation of Co0.5-xNixZn0.5Fe2O4 (x = 0 to 0.3) nanoferrites. The inverse spinel structure of the samples was clearly shown by the structural analysis of X-ray Diffractometer (XRD) and Fourier Transform Infrared (FTIR) Spectroscopy. We have studied the effect of sintering temperature (500oC) on the lattice constant and particle size using XRD. The average lattice parameters for the non-sintered and sintered samples were 8.377 Å and 8.354 Å respectively. For the non-sintered sample, the nickel concentration decreases the lattice parameter from 8.354 Å to 8.310 Å due to its smaller ionic radii than that of cobalt. While for a sintered sample at 500oC, the lattice parameter increases for concentration x=0.3 due to the thermal effect. The particle size calculated by Transmission Electron Microscope (TEM) agrees well with that of XRD. The morphological and compositional analysis was done with the help of Scanning Electron Microscopy (SEM) and the attached Energy Dispersive X-ray (EDX) Analyzer. The increasing percentage of nickel with decreasing percentage of cobalt shows that the cobalt is substituted by Nickel. The magnetic properties were studied by Vibrational Spectrometer (VSM). The value of saturation magnetization is higher for x=0.1 but lower for x=0.2 and 0.3 due to their particle size. The hysteresis loop of the samples their superparamagnetic behavior at room temperature.

Remediation of cobalt from semiconductor wastewater in the frame of fluidized-bed homogeneous granulation process

Green and sustainable strategies aim for the development of manufacturing processes that maximize the use of resources, instigating the semiconductor industry to adopt zero-liquid discharge policies. Complexity and variations in semiconductor wastewater effluents open an opportunity for resource recovery. One such opportunity is the potential recovery of heavy metals such as cobalt and/or copper in chemical-mechanical polishing wastewater, and inorganic anions such as phosphate from etching and acid cleaning. The present work demonstrates the capabilities of homogeneous crystallization in fluidized-bed reactor as treatment technology to process water effluents for industrial reuse while simultaneously recovering precious resources such as copper, cobalt and phosphate. Experimental results revealed that the optimum conditions were achieved at effluent pH of 7.75 – 8.0 and [PO4−3]/[Co2+] of 2.0. Uniform crystal growth was attained due to appropriate fluidization and proper collision of the particles at up flow velocity 40.11 m h−1 with 1.18 kg Co2+ m−2 h−1 loading. Performance was based on the removal/recovery capabilities of cobalt as heavy metal pollutant. The percentage of total cobalt recovered by granulation was 98.8%, whereas 99% cobalt removal was attained at optimal parameters. Coexistence of EDTA and citrate inhibits crystal growth, decreasing the metal granulation capability ~35%. Mixing of copper and cobalt ions in fluidized-bed homogeneous crystallization process was also investigated in which the highest granulation of 95.9% was attained at effluent pH of 6.50 for copper, and 96.8% at effluent pH of 7.50 for cobalt with an equimolar metal concentration of 7.0 mM and phosphate-metal molar ratio of 1.60. The granules recovered were analyzed using XRD and SEM-EDS. The recovered crystals were identified as mineral libethenite (Cu2(PO4)OH) and cobalt phosphate hydrate (Co3(PO4)2.8H2O).

Exsolution Enhancement of Metal-support CO Oxidation Perovskite Catalyst with Parameter Modification

This study aimed to further tune the capability of active metal exsolution onto the surface of the CO oxidative perovskite catalyst La 0.7Ce 0.1Co 0.3Ni 0.1Ti 0.6O 3 by tuning the reducing parameter. Under same calcination temperature of 800°C, XRD analysis shown that the precursors with calcination duration of 6 hours (S 2T 8H 6) was able to achieve similar crystalline structure to those with calcination duration of 12 hours (S 2T 8H 12). In order for the active metal (CoNi) to be exsolved onto the perovskite surface, reducing parameter such as temperature and duration are deemed crucial to the reduction process. The exsolution of the active metals was observed when the samples were treated under reducing condition with varying temperatures of 550°C and 700°C and duration from 200 to 300 minutes. Through comparison with their EDX readings, S 2T 8H 6 treated under 700°C and 300 minutes (S 2T 8H 6-R 7H 5) achieved the highest weight percentage of surface Cobalt and Nickel of 3.83 and 2.81. It was clear that by tuning the temperature and duration of reduction, the exsolution of the active metals onto the surface of the perovskite could be improved resulting in better exposure and dispersion of active metals onto the surface of catalyst.

Effect of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys

Various types of titanium base alloys are utilized as implant materials and as minis crews in orthodontics. The purpose of the current study is to enhancing titanium-based alloys with the additions of Cobalt in different percentage (5%, 10%, and 15%) to enhance primary osteoblast attachment and implant tissue incorporation. the reaction between human MG63 osteoblast-like cells and titanium – cobalt alloy face is substantial in biomaterials and tissue engineering field. The major target was to estimate the proteomic response of MG63 osteoblast-like cells in various cobalt percentages. The samples with and without cobalt addition was produced by using powder technology in order to get an acceptable initial surface roughness. Also sample characterizations includes (scanning electron microscopy (SEM), X-ray diffraction (XRD), vitro test (Biocompatibility MTT assay with MG-63 Cells). Results obtained from XRD and microstructure observations, sample without cobalt addition refer to an alloy with single I± phase, while after the additions of cobalt in different percentage (5%, 10%, 15%) the samples consist of two I±-Ti and intermetallic compound Ti2Co and the amount of Ti2Co phase slightly increase with increasing cobalt content. From MTT assays Proliferation and cells attachment of MG63 were cultured after 2 days Cells grown for the pure titanium alloys possess finer and circular confines compared with the grown cells at (titanium – cobalt) alloys with all cobalt percentages. Rising cobalt percentage makes the MG63 cell sharper and enlarges which means cobalt aid to enhancing both cell proliferation and growth. Cytotoxicity Cell Viability results was kept, exhibition no kind of attack caused by titanium or cobalt materials, The feature, of cobalt additions, in contrast to commercial pure titanium alloys, is the presence of active and non- cytotoxic compound (Ti2Co) which presents several attractive features, make the surface more attractive to the bone . How to Cite this Article Pubmed Style Fatimah J. Al-Hasani. of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. SRP. 2020; 11(5): 804-813. doi:10.31838/srp.2020.5.119 Web Style Fatimah J. Al-Hasani. of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. http://www.sysrevpharm.org/?mno=131488 [Access: March 30, 2021]. doi:10.31838/srp.2020.5.119 AMA (American Medical Association) Style Fatimah J. Al-Hasani. of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. SRP. 2020; 11(5): 804-813. doi:10.31838/srp.2020.5.119 Vancouver/ICMJE Style Fatimah J. Al-Hasani. of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. SRP. (2020), [cited March 30, 2021]; 11(5): 804-813. doi:10.31838/srp.2020.5.119 Harvard Style Fatimah J. Al-Hasani (2020) of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. SRP, 11 (5), 804-813. doi:10.31838/srp.2020.5.119 Turabian Style Fatimah J. Al-Hasani. 2020. of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Reviews in Pharmacy, 11 (5), 804-813. doi:10.31838/srp.2020.5.119 Chicago Style Fatimah J. Al-Hasani. Effect of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. Systematic Reviews in Pharmacy 11 (2020), 804-813. doi:10.31838/srp.2020.5.119 MLA (The Modern Language Association) Style Fatimah J. Al-Hasani. Effect of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. Systematic Reviews in Pharmacy 11.5 (2020), 804-813. Print. doi:10.31838/srp.2020.5.119 APA (American Psychological Association) Style Fatimah J. Al-Hasani (2020) of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Reviews in Pharmacy, 11 (5), 804-813. doi:10.31838/srp.2020.5.119

Optimization of the electrodeposition of the pure and cobalt doped copper oxide for solar cells and other applications

The control of structural properties of pure and cobalt doped cuprous oxide films is an available way to optimize the conditions of their deposition for better performance in solar cells and electrodes for photoelectrochemical (PEC) hydrogen production. In this study, series of Cu2O:Co thin films were synthesized using the electrodeposition method while varying the pH of the electrolyte, the applied potential and the percentage of cobalt. The found results reveal that with a pH of 12 and a potential of -0.35 V, the obtained band-gap energy is the narrowest with high carrier concentration. The band-gap can be further reduced by doping by cobalt with a percentage of 1%. The effect of OH− ions concentration on the atomic ratio Cu:O and the energy levels in the a band structures are assumed to be the underlying causes to interpret this optimization.

Electrodeposition of Zn-Co Alloy from an Acid Sulphate Bath Containing Triethanolamine and Thiaminehydrochloride

Electrodeposition of Zn-Co alloy from an acid sulphate bath has been carried out in this research work. The effects of metal ion ratio in the bath, pH current density, temperature, stirring, thickness and concentrations of triethanolamine and thiaminehydrochloride on the alloy composition and on cathodic current efficiency have been investigated. The deposition potentials of Zn-Co alloy are less noble of zinc and cobalt. The structure of Zn-Co alloy was investigated by X-ray diffraction indicates zinc structure. The surface morphology of alloy deposits is found to depend on the percentage of cobalt in the alloy. Under the optimum operating conditions, Zn-Co alloy deposition follows anomalous co-deposition.

Development of Cobalt coated MWCNTs/Polyurethane composite for microwave absorption

This research work describes the design and method of development of microwave absorber and was conducted for analysis of reflection loss performance with the magnetic modifications of Multi-Walled Carbon Nanotubes (MWCNTs). Cobalt coated Multi-Walled Carbon Nanotubes composites were prepared by three step methods. Composites were developed with varying weight percentage of Cobalt (II) Chloride Hexahydrate and Multi-Walled Carbon Nanotubes. The morphology, elementary analysis and absorbing properties of Cobalt coated Multi-Walled Carbon Nanotubes composites were studied by FESEM, EDX and Vector Network Analyzer. The obtained Co coated MWCNTs/PU composite demonstrated the maximum reflection loss of -21.06 dB at 12.63 GHz and the maximum absorption bandwidth of 3.7 GHz, in the frequency range of 8-13 GHz with 3 mm thickness. These microwave absorption parameters can be credited to synergistic effect of improved matched impedance and greater microwave attenuation properties of the absorber. The combined usage of dielectric loss and magnetic loss absorber design shows great diversity and can be a promising candidate for designing high performance microwave absorbing materials.

Nickel-cobalt alloy coatings prepared by electrodeposition Part II: Morphology, structure, microhardness, and electrochemical studies

A study was carried out to synthesize Ni-Co alloy coatings electrochemically from complex acidic glycine (gly) bath. The impacts of some operating parameters such as Co2+ to Ni2+ concentration ratios in the bath, gly concentrations, pH, applied current, plating time and temperature on the morphology of Ni-Co alloy were investigated. The microstructure, microhardness, and electrochemical studies were also investigated. The electrochemical studies utilized cyclic voltammetry, anodic linear stripping voltammetry, and potentiostatic current-time transient techniques. It was realized that gly lowers the cathodic overvoltage for the Co2+ deposition while promoting cathodic overvoltage of Ni2+ deposition. Accordingly, the concurrent codeposition of Co2+ and Ni2+ ions was simplified. The morphology of Ni-Co alloy is significantly dependent on the operating parameters rather than on the bath composition. Moreover, increasing either pH or bath temperature produces Ni-Co deposits free from cracking. The roughness of the alloy is decreased in the presence of gly as shown by the atomic force microscope (AFM) study. In the presence of gly, the microhardness increases from 387 to 970 kg f mm−2, i.e., it increased more than two-and-a-half times. On the other hand, X-ray diffraction analysis (XRD) data show that the crystallinity decreases with enhancing the percentage of cobalt in the deposits.

Retention of metals in periprosthetic tissues of patients with metal-on-metal total hip arthroplasty is reflected in the synovial fluid to blood cobalt transfer ratio in the presence of a pseudotumour

BackgroundModern metal-on-metal (MOM) arthroplasties were performed for over a decade before alarming reports of adverse metal reactions dramatically reduced their use. Failures are seen more often with high-wearing implants, but also well-positioned components with more favourable wear patterns can cause problems. There are no specific clinical indicators that could help us to predict the prognosis of these implants. For this reason, we still need more information on the effect of underlying factors that contribute to this process.MethodsIn this prospective cohort study, we investigated how cup orientation and type of pseudotumour determined by the Hart classification effect the distribution of metals in blood, synovial fluid and tissues surrounding the metal-on-metal hip prosthesis in revision surgery patients. One thousand two hundred twenty-nine metal-on-metal hip patients were screened and of those, 60 patients that had a revision surgery due to adverse metal reaction were included. Whole blood, synovial fluid and synovial/pseudotumour tissue samples were analysed for metal ion concentrations (Co, Cr, Mo and Ti).ResultsThe lowest metal concentrations were found when both cup anteversion and inclination were optimal, and the highest when both were suboptimal. Suboptimal anteversion alone raised Cr-ion concentrations more than suboptimal inclination. The concentrations of metals in blood, synovial fluid or synovial soft tissue were the same in patients with and without a pseudotumour, but the relative transfer percentage of cobalt from synovial fluid to blood was higher in patients with a pseudotumour.ConclusionsThe implant orientation alone does not explain the metal concentrations found in tissues or distribution of metals between different tissues. The accumulation of metals in periprosthetic soft tissues increase the total metal load, and in the presence of a pseudotumour this is reflected in the transfer ratio of Co from synovial fluid to the blood. The total metal load of the pseudotumour tissue should be defined in future studies to determine if this will provide new insights for clinical practice.

Experimental research of picosecond laser based edge preparation of cutting tools

In this study, using ultrafast lasers of 10 ps pulse duration as a precise and efficient method for cutting edge preparation is researched. Cutting edge preparation is an important step within cutting tool manufacturing, while unprepared sharp cutting edges show low stability, which leads to tool failure by high mechanical and thermal loads during the turning processes [C. F. Wyen, W. Knapp, and K. Wegener, Int. J. Adv. Manuf. Technol. 59, 899–914 (2012)]. The rounding of the edges requires laser manufacturing with high precision and minimal heat accumulation; thus, ultrafast lasers have been used in other investigations [M. Stolze, T. Herrmann, and J. L'huillier, Proceedings of ICALEO, Orlando, USA, ICALEO, Orlando, FL, October 23–27 (J. Laser Applications, Orlando, 2011)]. In the authors’ study, the effects of edge roundness on the cutting tool material WC-Co alloy were experimentally investigated. Samples with three different grain sizes and percentages of cobalt were used in the authors’ study. The experiments were carried out on the free surfaces of cutting tools under varying laser parameters including laser wavelength, fluence, and spatial pulse overlap (PO) in air or by using process gases (helium and oxygen). The impact of all these different laser parameters on the various material sorts was investigated. As a result, no reduction of the hardness of the original material was observed that could have a negative effect on the cutting ability of laser rounded cutting tools. By analyzing the surface quality of the ablated areas processed with different laser parameters mentioned above, a surface roughness below Ra = 0,15 μm was generated by using optimal fluence at both wavelengths of 1064 nm (IR) and 532 nm (VIS) and using a 70% spatial PO. Thus, a well-defined cutting edge with radii of 20–40 μm could be prepared.