Influence of temperature and pH value on deposition rate and corrosion resistance of Ni–Zn–P alloy coating

2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940013
Author(s):  
Yongfeng Li ◽  
Chengguo Fu ◽  
Lili Liu ◽  
Mingchao Liang ◽  
Yaming Liu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Deposition Rate ◽  
Ph Value ◽  
Chemical Properties ◽  
Alloy Coating ◽  
Industrial Applications ◽  
Complexing Agent ◽  
Solution Ph ◽  
Plating Bath ◽  
The Stability

The Ni–Zn–P alloy coating has excellent physical and chemical properties that have been exploited for various industrial applications. Using sodium citrate as a complexing agent and lactic acid as a stabilizer, the effects of temperature and pH on the deposition rate and corrosion resistance of electroless plated Ni–Zn–P coating were studied. The results indicated that, when the temperature was 85[Formula: see text]C, a good deposition rate was obtained with stable plating solution. pH value of 9.0 is preferred for the coating process by considering the stability of plating bath and deposition rate. The Ni–Zn–P alloy coating deposited with plating temperature of 85[Formula: see text]C and bath pH of 9.0 has good quality, and a uniform and smooth surface texture without porosity.

The Study about Environmentally-Friendly Passivation Technology Process and Performance on Brass Surface

2011 ◽  
Vol 399-401 ◽  
pp. 1967-1971
Author(s):  
Hong Yin Xu ◽  
Li Li
Keyword(s):  
Corrosion Resistance ◽  
Phytic Acid ◽  
Passive Film ◽  
Ph Value ◽  
Sodium Molybdate ◽  
Solution Ph ◽  
Sulfosalicylic Acid ◽  
Passivation Film ◽  
Brass Surface ◽  
And Performance

The paper through the synergy before mixed Phytic acid and Sodium molybdate, Sulfosalicylic acid, Organic silane, and add the active substances PEG, Optimize the Passivation liquid formula of Brass surface, Phytic acid is the main ingredient, study the affection of Phytic acid Passive film Corrosion resistance on the three main Passivation conditions: Passivation temperature, time and Passivation solution PH value. The results show that，Phytic acid passivation film process recipes as follows：Phytic acid (quality score 50%) 2~5ml/L, sodium molybdate 4~8g/L, organic material 10~30ml/L, sulfosalicylic acid 3~7g/L, polyethylene glycol 2~6g/L, deactivated temperature 30~35°C, pH value 5, deactivated time 60s. The test showed that，the phytic acid passive film can obviously enhance the anti-corrosive performance on the brass surface, its corrosion resistance proportion chromates passive film is fairly good.

scholarly journals Investigation of Calix[4]arene Molecule on Electroless Ni-P Alloy on Carbon Steel Substrate and Evaluation of its Corrosion Resistance in 3% NaCl

2020 ◽  
Vol 32 (6) ◽  
pp. 1384-1392
Author(s):  
N. M'hanni ◽  
M. Galai ◽  
T. Anik ◽  
M. Ebn Touhami ◽  
E.H. Rifi ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Deposition Rate ◽  
Electrochemical Impedance ◽  
Steel Substrate ◽  
Nickel Content ◽  
Chemical Deposition ◽  
Spectroscopic Studies ◽  
Sodium Hypophosphite ◽  
Complexing Agent ◽  
X Ray Diffraction

The autocatalytic nickel bath uses sodium hypophosphite as a reducing agent, sodium citrate as a complexing agent and sodium acetate as an accelerator. The effect of calix[4]arene molecule type H4L named (dicarboxylic acid p-tert-butylcalix[4]arene) was studied and used at various concentrations of 10-3 to 10-6 M to improve the microstructure, the microhadness and properties of nickel deposit obtained. The effect of varying the concentration of H4L, on the deposition rate, the composition, the microstructure and morphology of chemical deposition was studied. The results showed that depending on the concentration of calix[4]arene, the deposition rate decreases from 11, to 7.75 μm/h. The microstructure and microhardness improves significantly at a concentration of 10-6 M of additive. It was also shown that the coating obtained is adherent and compact and the chemical bath has become more stable in the presence of calix[4]arenic additives. Indeed, in both cases, the nickel content decreased with the addition of concentration. This decrease of nickel content might be related to the increase of deposition rate depending on the concentration. The X-ray diffraction analysis revealed peak intensification in the {111} orientation of plane in the presence of a concentration of 10-6 M; this may be in agreement with the results of metallographic study which showed that the coatings are adherent and have a good resistance. Hence, the Vickers microhardness of deposited coatings has a better value (376 HV) at the concentration 10-6 M. The corrosion resistance in 3% NaCl solution has been proven at the same concentration as found. Finally, the cyclic voltammetry and electrochemical impedance spectroscopic studies revealed that the additive strongly influences the cathodic process and affects slightly oxidation of hypophosphite.

scholarly journals Effect of Additives on Electrodeposition of Zinc-Nickel Alloy On Mild Steel

2019 ◽  
Vol 31 (4) ◽  
pp. 891-895
Author(s):  
Dinesh Kumar Chelike ◽  
K. Juliet Gnana Sundari
Keyword(s):  
Corrosion Resistance ◽  
Mild Steel ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Alloy Coating ◽  
Complexing Agent ◽  
Tafel Polarization ◽  
Good Corrosion Resistance ◽  
Ni Alloy ◽  
Strong Candidate

Considering the good corrosion resistance of Zn-Ni alloy, it is selected in the present study to be the protective coating on mild steel and it is considered as a strong candidate for the replacement of environmentally hazardous cadmium. Zn-Ni alloy coating is applied by electrodeposition at optimum temperature, current density and time. The bath solution used is consisting of EDTA as complexing agent. The electrodeposition is also carried out with tartaric acid and benzaldehyde additives to have good corrosion resistance and brightness. The electrodeposits obtained with and without additives are examined for nature and alloy composition. The corrosion behaviour of the electrodeposits is studied by Tafel polarization and electrochemical impedance spectroscopy.

scholarly journals Molecular Interactions in Binary Surfactant Solutions: Effect of pH

2019 ◽  
Vol 64 (4) ◽  
pp. 437-445
Author(s):  
Olga Kochkodan ◽  
Victor Maksin ◽  
Nadiya Antraptseva ◽  
Tetyana Semenenko
Keyword(s):  
Molecular Interactions ◽  
Mixed Micelles ◽  
Ph Value ◽  
Chemical Properties ◽  
Micelle Formation ◽  
Bulk Solution ◽  
Surfactant Mixtures ◽  
Solution Ph ◽  
Solution Interface ◽  
Adsorption Layers

By using surface tension and conductivity measurements, the colloid-chemical properties of the mixtures of cationic hexadecylpyridinium bromide with nonionic Triton X-100 surfactants were investigated both in the bulk solution and at air/solution interface at different pH values. The composition of mixed micelles and adsorption layers, parameters of molecular interactions in mixed micelles βm and adsorption layers βσ, as well as standard free energies of micelle formation ΔG0mic and adsorption ΔG0ads were calculated. It was found that molecules of the nonionic surfactant presumably dominate in the mixed micelles and adsorption layers. It was shown that βm and βσ have negative values, which indicate the strengthening of intermolecular interactions in the mixed micelles and adsorption layers. Based on the data obtained, it was suggested that ion-dipole interactions are involved in the formation of intermolecular structures between nonionic and cationic surfactants in aqueous solution and at the air-solution interface. It was shown that βm, βσ as well as ΔG0mic and ΔG0ads parameter depends on the solution pH value. The complex interplay of ion-dipole, protonation and chelation processes, which occur in the surfactant mixtures at different pH and affect the strength of intermolecular interaction, should be taken into account for data analysis.

scholarly journals The Immobilization of Lipases on Porous Support by Adsorption and Hydrophobic Interaction Method

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 744
Author(s):  
Nur Fathiah Mokhtar ◽  
Raja Noor Zaliha Raja Abd. Rahman ◽  
Noor Dina Muhd Noor ◽  
Fairolniza Mohd Shariff ◽  
Mohd Shukuri Mohamad Ali
Keyword(s):  
Ph Value ◽  
Continuous Process ◽  
Immobilized Enzymes ◽  
Industrial Applications ◽  
Adsorption Method ◽  
Porous Support ◽  
Microbial Lipases ◽  
The Stability ◽  
The Cost ◽  
Hydrophobic Supports

Four major enzymes commonly used in the market are lipases, proteases, amylases, and cellulases. For instance, in both academic and industrial levels, microbial lipases have been well studied for industrial and biotechnological applications compared to others. Immobilization is done to minimize the cost. The improvement of enzyme properties enables the reusability of enzymes and facilitates enzymes used in a continuous process. Immobilized enzymes are enzymes physically confined in a particularly defined region with retention to their catalytic activities. Immobilized enzymes can be used repeatedly compared to free enzymes, which are unable to catalyze reactions continuously in the system. Immobilization also provides a higher pH value and thermal stability for enzymes toward synthesis. The main parameter influencing the immobilization is the support used to immobilize the enzyme. The support should have a large surface area, high rigidity, suitable shape and particle size, reusability, and resistance to microbial attachment, which will enhance the stability of the enzyme. The diffusion of the substrate in the carrier is more favorable on hydrophobic supports instead of hydrophilic supports. The methods used for enzyme immobilization also play a crucial role in immobilization performance. The combination of immobilization methods will increase the binding force between enzymes and the support, thus reducing the leakage of the enzymes from the support. The adsorption of lipase on a hydrophobic support causes the interfacial activation of lipase during immobilization. The adsorption method also causes less or no change in enzyme conformation, especially on the active site of the enzyme. Thus, this method is the most used in the immobilization process for industrial applications.

Effect of pH Value on Preparation of La2CuO4 Microcrystallites Synthesized by Sol-Gel Process

2012 ◽  
Vol 512-515 ◽  
pp. 231-234 ◽  
Author(s):  
Yi Feng Li ◽  
Jian Feng Huang ◽  
Li Yun Cao ◽  
Jian Peng Wu
Keyword(s):  
Optical Band Gap ◽  
Ph Value ◽  
Raw Materials ◽  
Sol Gel ◽  
Complexing Agent ◽  
Solution Ph ◽  
Crystallization Property ◽  
Water As Solvent ◽  
Sol Gel Process ◽  
Single Sphere

La2CuO4 crystallites were prepared via a sol-gel process using lanthanum nitrate and cupric nitrate as raw materials, distilled water as solvent, citric acid as complexing agent and ammonia to control the pH value. The as-prepared La2CuO4 crystallites were characterized by XRD, FESEM, TEM and UV-Vis spectra. Results show that the crystallization property of La2CuO4 crystallites increases firstly and then decreases with increasing of the solution pH value from 1.0 to 2.5, but all of the samples exhibit single sphere-like morphology. It is found that when the solution pH value is controlled at 2.0, the grains display uniform distribution and the size ranges from 100nm to120nm after sintering at 600°C for 2 hours. The optical band gap of the as-prepared La2CuO4 crystallites is calculated to be 1.38eV.

Adsorption of Nickel and Cobalt Ions on Magnesium Silicate

2013 ◽  
Vol 726-731 ◽  
pp. 2855-2858
Author(s):  
Hua Yang ◽  
Hai Zeng Wang
Keyword(s):  
Ph Value ◽  
Average Pore Size ◽  
Chemical Properties ◽  
Magnesium Silicate ◽  
Solution Ph ◽  
Average Pore ◽  
Cobalt Ions ◽  
Physico Chemical ◽  
Short Time ◽  
Adsorption Desorption

Magnesium silicate (MS) was successfully prepared and the physico-chemical properties were determined by N2adsorption/desorption isotherm and Scanning Electron Microscopy (SEM). Surface area and the average pore size were 120 cm3·g-1and 10 nm. Adsorption experiments of removal of nickel and cobalt ions were investigated as the function of initial concentration, adsorbent dose, adsorption time and solution pH value. The maximum removal was reached with pH equal to 5 for the removal of nickel and cobalt ions. Adsorption process was rapid and adsorption equilibriums were attained in a short time.

The Influences of Additives and Heat Treatment on the Properties of Electroless Plating Ni-W-Mo-P Alloy on the Aluminum

2014 ◽  
Vol 941-944 ◽  
pp. 1585-1588
Author(s):  
Zu Xiao Yu ◽  
De Tao Zheng ◽  
Hong Guo ◽  
Yong Liu ◽  
Yuan Liang Luo ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Corrosion Resistance ◽  
Deposition Rate ◽  
Electroless Plating ◽  
Corrosion Potential ◽  
Alloy Coating ◽  
Corrosion Current ◽  
Maximum Hardness ◽  
Corrosion Properties

To improve the wear resistance and anti-corrosion properties of the aluminum, the electroless plating Ni-W-Mo-P alloy on the aluminum is necessary. The influences of heat treatment and additives (stabilizers) on the porosity, deposition rate, corrosion current, corrosion potential, microhardness and wear resistance of electroless plating Ni-W-Mo-P alloy coating, were investigated using electrochemical methods, etc. The results show that the deposition rate and anti-corrosion properties of electroless plating Ni-W-Mo-P are improved when the stabilizers, including KI (1mg/L) and “KIO3 (1mg/L) + Pb (Ac)2 (1mg/L)”, are added into bath, respectively. In addition, the maximum hardness (902 HV) and good wear resistance of Ni-W-Mo-P coatings are obtained when heated at 400°C (1h). However, its corrosion resistance is worse. Its microhardness is also obviously improved after heated at 200°Cfor 6 h, and the microhardness reaches to 950 HV.

scholarly journals Current Status of Research on Electrodeposited Ni-W Alloy Coating

2021 ◽  
Vol 261 ◽  
pp. 02085
Author(s):  
Lan Zhan ◽  
Zhen Ma ◽  
Bing Li ◽  
Mingzhong Wu ◽  
Xiangge Qin ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Ph Value ◽  
Composite Coatings ◽  
Ternary Systems ◽  
Alloy Coating ◽  
Amorphous Structure ◽  
Current Status ◽  
Electroplating Process ◽  
The Relationship ◽  
Influence Of Ph

This paper discusses the influence of pH value, temperature and current density on the crystalline and amorphous structure of Ni-W alloy coatings during the electroplating process. The relationship between the corrosion resistance of Ni-W alloy coating and its crystal structure is discussed. In addition, the most common types of ternary systems and composite coatings for electrodeposited Ni-W alloy coatings are introduced. The effects of element types and contents on the hardness, wear resistance, corrosion resistance and thermal stability of Ni-W alloy coatings are analyzed. Finally, the current problems and development directions of Ni-W alloy coatings are proposed.

Study of Pb2+, Cd2+ and Ni2+adsorption onto activated carbons prepared from glycyrrhiza residue by KOH or H3PO4 activation

2015 ◽  
Vol 72 (3) ◽  
pp. 451-462 ◽  
Author(s):  
Chunfang Ma ◽  
Wei Fan ◽  
Jinbao Zhang ◽  
Yang Shi ◽  
Ningchuan Feng
Keyword(s):  
Activated Carbons ◽  
Ph Value ◽  
Raw Materials ◽  
Chemical Properties ◽  
Kinetic Studies ◽  
Physical Structure ◽  
Micropore Volume ◽  
Solution Ph ◽  
Analytical Instruments ◽  
H3po4 Activation

The activated carbons (ACs) were prepared from glycyrrhiza residue by KOH or H3PO4 activation and were used for removing Pb2+, Cd2+ and Ni2+ from simulated wastewater. The changes of the physical structure and chemical properties of the glycyrrhiza residue before and after activation were characterized by using a variety of analytical instruments and methods. Kinetics and equilibrium isotherms were obtained and the effects of solution pH value and adsorbent dosage were studied in batch experiments. The results indicated that after activation, the surface structure of glycyrrhiza residue changes and surface area, micropore volume also increase accordingly. Kinetic studies showed that the adsorption followed a pseudo-second-order reaction. The Freundlich model fitted the equilibrium data better than the Langmuir isotherm. According to the Langmuir equation, the maximum adsorption capacities of ACs prepared from glycyrrhiza residue by KOH and H3PO4 activation for Pb2+, Cd2+ and Ni2+ are 2.170 mmol/g, 2.617 mmol/g, 3.741 mmol/g and 2.654 mmol/g, 3.095 mmol/g, 3.076 mmol/g, respectively, which are much higher than ACs prepared from other raw materials.

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