Effect Of Bath pH Research Articles

Electrodeposition of Cu2O thin Film Onto Copper Substrate by Linear Sweep Voltammetry at Low Duration: Effect of Bath pH

Copper (II) oxide (Cu2O) has attracted much interest as a semiconductor material for solar cell applications. Here we report the synthesis of Cu2O, thin films through an economical and simple electrodeposition method at low duration (10 min) by linear sweep voltammetry (LSV) method at 50 °C bath temperature, with the use of citric acid as a complexing agent. The influence of pH value (pH = 9.5, 10.5, 11.5, and 12.5) on structural, morphological, and optical properties of the synthesized Cu2O thin films onto copper substrate was investigated. The synthesized Cu2O thin films have been characterized using various techniques like X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM-EDX), UV-vis spectrophotometry. The X-ray diffraction showed that the deposited thin films at pH= 9.5, 10.5, 11.5 matched well with the cubic (Pn-3m) structure and showed an improvement of the crystallinity near the value pH=10.5. Raman spectroscopy confirms the cubic structure of the synthesized thin film. Thin films show a high absorption coefficient in the visible spectra, and the calculated band gap energy value is near 1.8 eV.

The effect of bath pH on electrodeposition and corrosion properties of ternary Fe-W-Zn alloy platings

As a new trial to improve the corrosion resistance of the Fe-W alloy platings, Fe-W alloys incorporating a small amount of Zn, namely novel ternary Fe-W-Zn alloy platings, are prepared by constant current electrolysis using citrate-ammonia baths. In this study, the effects of bath pH on elemental composition, morphology, plating structure, and corrosion resistance of the electrodeposited ternary alloy platings are investigated. The W content of the electrodeposited alloys showed a maximum of 31.5 at.% at pH 8.0 and an inverse correlation was observed between the W content and current efficiency in the investigated pH range. The Zn content tended to decrease with increasing bath pH, and the structure of alloy platings gradually refined along with the increase in the amount of Zn incorporated into the Fe-W alloy. Potentiodynamic polarization test results reveal fine granular structured ternary Fe-W-Zn alloy prepared at pH 8.0, containing approximately 1.6 at.% of Zn, which showed distinctly enhanced corrosion resistance in a 1 M H2SO4 solution compared to binary Fe-W alloy and ternary alloys prepared at pH 6.0, 7.0, and 9.0. It has been found that the bath pH has a great influence on the elemental composition of the ternary alloys, which significantly affects the plating structure and corrosion resistance of the alloy platings.

The Effect of Bath pH and Temperature on the Corrosion Behavior of Co-Electrodeposited Ni-Cu/Cr2O3 Nanocomposite Coatings

The aim of this work was to assess the influence of pH and temperature of bath plating on the performance of Ni-Cu/Cr2O3 nanocomposite coatings in a corrosive environment. For this purpose, Ni-Cu/Cr2O3 nanocomposite coatings were successfully carried out on the carbon steel by co-electrodeposition method from an aqueous composing of H2O, NiSO4, NiCl, CuSO4, Na3C6H5O7, and H3BO3 with and without 6 g/L Cr2O3 nanoparticles. The microstructure of samples was studied by x-ray diffraction and scanning electron microscopy, and corrosion behavior of the coatings was assessed by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in the 3.5% NaCl solution. It was observed that by increasing the bath pH from 3 to 7 the corrosion current density (icorr) determined by Tafel extrapolation method was changed from 7.4 to 12.5 µA/cm2 and that polarization resistance (RP) obtained from EIS measurements was decreased from 850 to 452 Ω·cm2. The values of icorr and RP were changed from 11.2 µA/cm2 and 514 Ω·cm2 to 6.1 µA/cm2 and 1265 Ω·cm2, respectively, as the bath temperature was varied from 25 to 45 °C. Compared to the Ni-Cu nanocrystalline coating, the value of Rp showed more than 324% improvement when co-electrodeposition of Ni, Cu, and Cr2O3 was carried out at a temperature of 45 °C and pH value of 4.5.

Electroless nickel underlayer deposited between copper filler and silicon substrate: effect of bath pH

ABSTRACT This research proposed intermediate materials between Cu filler and Si wafer to reduce the coefficient of thermal expansion (CTE) mismatch in the through silicon via (TSV) structure. The proposed material is Ni underlayer because it has CTE value between Cu and SiO2 which is 13 ppm/°C (Cu = 17 ppm/°C, SiO2 = 0.6 ppm/°C). The deposition process of nickel underlayer was conducted using electroless deposition process at various pH value (4.5, 5.5 and 6.5) of plating bath and deposition time (20, 40 and 60 minutes). The deposition behaviour was studied through surface and cross-sectional analysis under scanning electron microscopy (SEM). The Ni thickness was measured using cross-sectional analysis under SEM. The chemical composition of Ni deposits was measured using energy dispersive spectroscopy equipped on SEM. The performance test analysis was conducted using Standard ASTM D3359 (Cross Hatch Tape-Test) for coating adhesion test and 4-Point Probe Test for resistivity measurement. It was found that the optimum pH of the Ni bath is 6.5 due to high stability of plating bath to form uniform Ni deposited on silicon wafer. These optimum coating parameters showed homogeneous and uniform distribution of Nickel deposited on the surface of silicon with excellent adhesion properties for all pH value.

Chemical bath pH influence on the structural, morphological and optical properties of zinc sulphide thin film prepared from acidic baths

Zinc sulphide (ZnS) thin films were prepared on glass substrate by using solution growth method from acidic chemical bath. The effect of bath pH on the physical and chemical properties of ZnS thin films were established well. The synthesized thin films were characterized by different techniques to study how bath pH affects the nature of the ZnS thin films. The XRD study established that the prepared ZnS thin films had a cubic crystal structure. The XRD results further showed that the diffraction peaks around 28.7° and 48.1° enhanced as the bath pH increased. The SEM study confirmed that the bath pH play significant role on the nature of the surface morphology of ZnS thin film deposited in acidic chemical bath. The EDS study confirmed the presence of the constituent elements Zn and S. This measurement also shows that the prepared ZnS thin films were in a good stoichiometric ratio (Zn/S). The optical band gap of the prepared thin films found in the range of 3.24 eV to 3.89 eV as the bath pH decreased from 4.86 to 4. Irrespective of bath pH, all the deposited ZnS thin films exhibited a strong PL emission in red region, however, the intensity of the PL emissions were varied with bath pH.

Effect of Bath pH on Electronic and Morphological Properties of Electrodeposited Cu2O Thin Films

The ability to systematically vary the flatband potential and the band edge positions of Cu2O by varying the deposition bath pH is considered important in the context of using Cu2O for photocatalytic water splitting. Capacitance-voltage (C-V) and dark and light current-voltage measurements were taken in order to investigate the electronic properties of electrodeposited Cu2O thin films grown in an acetate bath containing a 0.01 M Cupric Acetate having different bath pH values. The Mott-Schottky plots resulting from C-V measurements revealed that the flatband potential and doping density of the films strongly depended on the deposition bath pH. For pH values lower than 7.2, conductivity of Cu2O films remained n-type while it changed to p-type for higher pH values indicating that change of n-type to p-type character of the Cu2O films can be controlled by the bath pH. With increasing pH value, the grain size decreased, while crystal shapes transformed from truncated octahedral to cubic within the tested pH range. A well ordered cubic structure was observed in films deposited at pH 7.8. The rate of deposition decreased at higher pH values leading to thinner films indicating the effect of pH on the film thickness. Calculated band edge positions of conduction and valance bands of the Cu2O films were −4.19 eV and −6.29 eV respectively with respect to the vacuum level.

Studies the effects of bath pH and lead molar concentrations on the structural, optical and electrical properties of lead sulphide thin films prepared by chemical route

Lead sulphide (PbS) nanocrystalline thin films were prepared by chemical bath deposition route from two different chemical baths. The first bath (bath-A) was synthesized by varying the volume of ammonia to study the effect of bath pH, while the second bath (bath-B) was complexed by potassium hydroxide and the effect of lead molar concentrations were investigated. The X-ray diffraction analyses confirmed that all deposited thin films from the two baths had face centered cubic crystal structure. The XRD results also verified that the crystalline size increased from 25 to 40 nm when lead molar concentration decreased to 0.1 M. The HRTEM images showed that the grains are grown along different planes which confirmed a typical polycrystalline nature of the deposited PbS thin films from both chemical baths. The elemental analyses were carried out by EDX and confirmed the formation of PbS compound. The optical absorption study showed that the lowest optical band gap of 0.81 eV was estimated from bath-B at 0.1 M lead concentration, whereas, a highest band gap of 1.57 eV was found from bath-A. The transmittance study verified that the transmittance was increased with the wavelength and the maximum transmittance was measured around 24.51% for pH 10.5. The photoluminescence study revealed that the PbS thin film exhibited a broadband emission spectra from 410 to 625 nm regardless of bath pH and lead concentration. The dc-two point probe measurement verified that the electrical properties of the PbS thin films were considerably changed by bath pH and lead molar concentrations. The room temperature resistivity of the thin films found in the order of 104 Ω cm.

Effect of pH on the characteristics of electroless Ni-P coatings

In this study electroless Ni-P coatings were deposited on W302 steel substrates. The effects of bath pH and heat treatment at 400?C were investigated on the surface morphology, phase structure, phosphorus content, thickness and microhardness of the coatings. It was observed that both the phosphorus content and coating thickness are dependent on the bath pH. In an acidic/neutral bath, low and medium phosphorus coatings with thickness of 13.9-19.8 ?m were synthesized, while in an alkaline bath, high phosphorus, 4.8-5.8 ?m-thick coatings were formed. Coatings containing medium or high P seemed to be amorphous, while low P coatings had microcrystalline structures. Hardness was also dependent on the composition of the coating. After heat treatment, the structure of the coatings transformed into crystalline Ni with the precipitation of Ni3P phases, which resulted further increases in hardness.

Effect of pH of the galvanic bath on electrodeposition of Cu-Mn3O4 composite coatings

Cu-Mn3O4 composite coatings were prepared on the SUS 430 steel by means of the electrodeposition in an alkaline copper pyrophosphate bath containing Mn3O4 particles. The effect of bath pH on the content of Mn3O4 co-deposited in Cu matrix was investigated by electrochemical measurements including zeta potential, cathodic polarization and electrochemical impedance spectroscopy (EIS). The results showed that pH had a significant influence on co-deposition of Mn3O4 in Cu matrix. It was found that the absolute value of zeta potential of Mn3O4 particle, cathodic overpotential and Faraday resistance reached the maximum when the bath pH was adjusted to 9 or 9.5, which implied that mass fraction of co-deposited Mn3O4 particles in composite coating obtained at pH of 9 or 9.5 would be higher than those at other pH values. The compositions and microstructures of Cu-Mn3O4 composite coatings obtained at different pH values were consistent with the results of electrochemical analyses. The mass fraction of co-deposited Mn3O4 was highest (8.02 wt%) at pH of 9. It was proved that electrochemical tests were of great significance to ascertain suitable pH for Cu-Mn3O4 composite electrodeposition. Scratch test indicated the critical load (Lc) of the composite coating obtained at pH of 9 was 21.4 N.

EFFECTS OF pH ON Ni COATING ON POLY(ETHYLENE TEREPHTHALATE) SUBSTRATE BY PRINTING PRIME IN COMBINATION WITH PALLADIUM ACTIVATING

In this work, the primer-printed and then self-assembled poly(ethylene terephthalate) (PET) sheets were plated when the bath pH increased from 7 to 11. The effects of bath pH on the structural and electrical properties of electroless nickel plating were investigated systematically using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that the crystallographic structures of Ni-plated PET (NPP) sheets were face centered cubic, the preferential orientation of the coatings changes from (200) plane to (111) plane, the growth rate of plated nickel coating increased from 3.71[Formula: see text][Formula: see text]m/min to 8.13[Formula: see text][Formula: see text]m/min, the average Ni crystal size was increased from 0.23[Formula: see text][Formula: see text]m to 0.92[Formula: see text][Formula: see text]m, the average EMI-SE of NPP sheets was increased from 37.2[Formula: see text]dB to 38.6[Formula: see text]dB and the surface electrical resistivity of NPP sheets was decreased from 6235[Formula: see text]ohm [Formula: see text] cm to 0.03[Formula: see text]ohm [Formula: see text] cm with the increase of bath pH. The changes in structural and electrical properties were most possibly due to the fact that the thickness of coating increased.

Effects of bath pH on structural and electrochemical performance of Cu2O

Well-defined cuprous oxides (Cu2O) with different morphologies were successfully deposited on fluorine-doped tin oxide (FTO)-covered glass substrates by potentiostatic deposition. The effect of the pH values on the crystal morphologies of Cu2O was studied. The as-prepared products were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and UV-visible spectroscopy. The typical XRD patterns revealed that all Cu2O thin films were pure Cu2O phase. Different crystal morphologies of Cu2O could be obtained by varying pH. The Cu2O thin film was composed of a large number of star-like shape grains with the pH of 4.8. With a further increase of the pH, the Cu2O film showed the uniform dendrite morphology. LSV uncovered that E R (reduction potential of Cu2+ to Cu+) increased with the pH value enlargement. According to the EIS, diffusion coefficient of Cu2+ ion was reduced with the increase of the pH. The UV-vis absorption spectra revealed that the broad absorption peaks were from 300 to 500 nm and the evaluated band gap of the films was tunable in the range of 2.02–2.67 eV, with the variation of the pH values. According to the experiment and relevant literatures, the probable electrodeposition mechanism of the Cu2O was discussed.

EFFECT OF BATH pH ON ELECTROLESSNi–PCOATING DEPOSITED ON OPEN-CELL ALUMINUM FOAMS

Different electroless Ni – P coatings were deposited on open-cell aluminum foams at various bath pH. The effect of bath pH on the morphology, structure, components, phases and corrosion resistance of the Ni – P coating was studied by scanning electron microscopy (SEM), confocal laser scanning microscope (CLSM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), immersion test and electrochemical polarization measurement, respectively. The experimental results show that the bath pH not only changed the reactivity of the bath, but also had a influence on the microstructure and anticorrosive property of electroless Ni – P coating. The high pH bath raises the thickness of Ni – P coating but decreases the content of phosphorus element in the Ni – P coating. The corrosion resistance of the coated aluminum foams increases when the bath pH rises.

Cu2O photoelectrodes for solar water splitting: Tuning photoelectrochemical performance by controlled faceting

Cuprous oxide (Cu2O) films were grown by electrodeposition in aqueous solutions of varying pH. The effect of bath pH on morphology, structural, and photoelectrochemical (PEC) properties of Cu2O films was investigated. XRD showed that all prepared films were polycrystalline Cu2O, without formation of competing phases such as CuO and Cu. The film grown in the solution with a pH of 8 is made up of Cu2O crystallites with preferential (200) planes exposed. The films deposited at solution pH values of 10, 12 and 14 exhibit Cu2O crystallites with preferential (111) planes exposed. As photoelectrodes these Cu2O films generate photocurrent upon light illumination. The Cu2O film grown in the solution with pH of 12 shows the best PEC performance for hydrogen generation. The (111) facets of the Cu2O film were stable without corrosion during the PEC test. A mechanism for the preferred faceting in alkaline solution has been discussed.

The Effect of Bath Ph on the Phase Formation of Ternary Co-Ni-Fe Nano-Coatings

This study describes how the control of bath pH allows different types of phase formation in the ternary Co-Ni-Fe nanocoating. The acidity of the plating bath has been known as a main factor to the properties of coatings. The Co-Ni-Fe coating was fabricated using a commercial electrodepostion process. Several pH solutions (3, 7 and 9) were employed to determine the optimum condition for Co-Ni-Fe synthesis. The bath pH was varied by using sodium hydroxide (NaOH) and sulphuric acid (H2SO4). Other parameters such as temperature, electrolyte composition, deposition time and current density were kept constant. The experiment was performed at 50°C. This temperature is commonly used in the industrial plating process. XRD analysis indicated the presence of both phases: body centred cubic (BCC) and face centred cubic (FCC) dependent on the pH value. Co-Ni-Fe nanocoatings obtained from the electrolyte of low pH showed the fine-grain morphology. The hardness of the Co-Ni-Fe nanocoatings was closely related to the obtained morphology.

Effect of bath pH and stabilizer on electroless nickel plating of magnesium alloys

In order to develop the new bath solutions with long cycles and high stability for electroless nickel (EN) plating of magnesium alloys, effect of bath pH and pH stabilizers on plating rate and coating quality as well as bath life were studied in detail. Gravimetry was used to determine the deposition rate of coating. The coverage of coating was evaluated by 2h of immersion test for magnesium alloys in 3.5wt.% NaCl solution. The results showed that the bath pH not only changed the reactivity of the bath, but also had a strong impact on the microstructure and electrochemical properties of coatings. A highly uniform and dense coating was formed via EN plating in the new bath containing ammonium acetate. The bath life was extended when appropriate amount of ammonium acetate was added. It was effective for ammonium acetate to stabilize pH in the plating solution, to control coating quality and bath life.

Oxide p‐n Heterojunction of Cu2O/ZnO Nanowires and Their Photovoltaic Performance

Oxide p‐n heterojunction devices consisting of p‐Cu2O/n‐ZnO nanowires were fabricated on ITO/glass substrates and their photovoltaic performances were investigated. The vertically arrayed ZnO nanowires were grown by metal organic chemical vapor deposition, which was followed by the electrodeposition of the p‐type Cu2O layer. Prior to the fabrication of solar cells, the effect of bath pH on properties of the absorber layers was studied to determine the optimal condition of the Cu2O electrodeposition process. With the constant pH 11 solution, the Cu2O layer preferred the (111) orientation, which gave low electrical resistivity and high optical absorption. The Cu2O (pH 11)/ZnO nanowire‐based solar cell exhibited a higher conversion efficiency of 0.27% than the planar structure solar cell (0.13%), because of the effective charge collection in the long wavelength region and because of the enhanced junction area.

Improvement on Hardness of 6061 Al Alloy Using an Electroless Ni-P Coating

The surface morphology and hardness of electroless Ni–P alloy plating on 6061 aluminum alloys substrate in an alkaline plating bath with sodium hypophosphite as reducing agent were investigated. The effects of bath pH on the plating rate, compositions and surface morphology of theelectroless Ni-P deposits were studied. The results showed the deposition rate of the electroless Ni–P deposits increased with the rise of the bath pH, while the P content decreased. Scanning electron microcopy (SEM) of the deposits showed nodular structure for the deposits. Hardness data of the Ni-P coatings indicated that electroless Ni–P plating could obviously improve the hardness of 6061aluminum alloy.

Electrodeposited copper oxide films: Effect of bath pH on grain orientation and orientation-dependent interfacial behavior

Copper (I) oxide (Cu 2O) films were cathodically electrodeposited on Sn-doped indium oxide substrates. The influence of electrodeposition bath pH on grain orientation and crystallite shape was carefully re-examined using X-ray diffraction and scanning electron microscopy. In addition to the (100) and (111) preferred orientations identified in two previous sets of studies, as the bath pH was varied in the present study from ∼ 7.5 to ∼ 12, a third preferred orientation, (110), was identified in a narrow pH range, ∼ 9.4 to ∼ 9.9. A remarkable shift in the flat-band potential (spanning ∼ 500 mV) was measured in a non-aqueous electrolyte medium for the various Cu 2O samples obtained from baths of varying pH.

Effect of bath pH on Nickel Citrate electroplating bath

Effect of bath pH on Nickel Citrate electroplating bath

Testing the Role of Metal Hydrolysis in the Anomalous Electrodeposition of Ni‐Fe Alloys

With the objective of testing several models of the “anomalous codeposition” (ACD) encountered in the electrodeposition of nickel‐iron alloys, the effects of bath pH and complexing agents on the composition of deposits were examined. When the pH of the “base line” bath was increased from 3.0 to 5.0, the Ni/Fe mass ratio of the deposit increased (i.e., the deposition became less anomalous). The presence of tartrate ion in the bath produced a slight decrease in the Ni/Fe of the deposit. This complexing agent complexes ferric ion and thus prevents its precipitation but has little interaction with ferrous ion or nickel ion under the electrodeposition conditions examined. The addition of ethylenediamine to the bath produced a significant increase in the Ni/Fe mass ratio. This complexing agent does not interact significantly with ferric ion or ferrous ion under the test conditions. None of these observations are consistent with the Dahms and Croll model of ACD. The effects of pH and tartaric acid on the deposit composition are consistent with the predictions of the Grande and Talbot model and the Matlosz model. The effect of ethylenediamine is not consistent with the Grande and Talbot model, but may be interpreted within the framework of the Matlosz model and the Hessami and Tobias model.