Production of Nano-Composite Hydroxyapatite-Based Coatings through Reverse Pulse Electroplating

2021 ◽  
Author(s):  
S M Nazmuz Sakib

Since the discovery of synthetic HAp in the 1950s, hydroxyapatite is becoming a significant covering material for bio implants. A regulated surface roughness/porosity, appropriate chemical resistance, and a desirable tri-biological behavior are required for HAp coatings. On substrates with a variety of structure, composition, size, and shape, the coating process must be applied at varied scales and at a fast enough rate. There is a full description of both dry and wet coating procedures included in this article. Cathode efficiency fell as tc- increased, although it was still better than DC coatings. In this paper, the mechanism of HAp electrodeposition is examined, as well as the effect of operational variables on deposit characteristics. Recent advances in the field are critically examined. HAp composite coatings, including those reinforced with metallic, ceramic, and polymeric particles, as well as nanotubes, modified graphene’s, chitosan, and heparin, are discussed in depth. On the other hand, a glance towards the future in the field of electrodeposited HAp coatings is taken. Different experimental parameters were explored to establish the optimal reaction conditions for HA-Ag nanocomposites. Pulse reverse plating (PRP) in combination with an anionic surfactant, sodium dodecylsulphate (SDS), was utilized for the first time to generate nanocomposite Co-Al2O3 electrodeposited coatings, using a technique similar to that used for Co – IF WS2 deposition in prior work. The optimal plating setups in the pulse-reverse electroplating (PRP) mechanism for non-anomalous plating of Co–Ni deposits (i.e., the metal composition of deposits equals that of the plating solutions) from chloride solutions were determined using experimental strategies such as fractional factorial design (FFD), path of steepest ascent, and central composite design (CCD) combined with the response surfaces (RSM). The FFD research found that the potentials and time duration of pulse-plating had a significant impact on the composition of Co–Ni deposits. The two parameters were the sharpest ascending route and the best circumstances for non-anomalous plating of Co–Ni layers. NiFe thin films produced by pulse reverse (PR) electrodeposition are potential alternatives for the next phase of core magnetic materials that will be utilized in high shifting frequency magnetic elements. For statistical modeling and analysis of the nickel electroplating process outcomes, the central composite experimental design and response surface technique were used. The empirical models developed in terms of design variables (current density J (A/dm2), temperature T (C), and pH) were found to be statistically adequate to describe the process responses, namely cathode efficiency Y%, coating thickness U (m), brightness V%, and hardness W%. (HV). The response surfaces were explored and analyzed using graphical representations consisting of 2D contour plots and 3D surface plots in order to determine the main, quadratic, and interaction effects. The desirability function method was used to do multi-response optimization of the nickel electroplating process. To this aim, a genetic algorithm was employed to solve the multi-response issue mathematically. The optimization method resulted in the Pareto optimum set, which is a collection of similar solutions.

1999 ◽  
Author(s):  
Xiaobin Li ◽  
Siddharth Kiyawat ◽  
Hector J. De Los Santos ◽  
Chang-Jin “CJ” Kim

Abstract Narrow beamwidth is highly desirable for many micromechanical elements moving parallel to the substrate. A good example is the electrostatically driven flexure structure, whose driving voltage is determined by the width of the beam. This paper presents the process flow and the result of a high-aspect-ratio electroplating process using photoresist (PR) molds. Following a systematic optimization method, PR molds with aspect ratios up to 4.0 were fabricated with a beamwidth of only 2.1μm. Higher aspect ratios, up to 6.8, were achieved using PR double coating technique, with a beamwidth of 2.6μm. Using a Cr/Cu seed layer, nickel electroplating was successfully carried out to translate the PR molds into nickel micro-structures. We observed bend-down of the fully released nickel cantilevers that are over 8μm thick. Further investigation suggested a combined effect of residual stress gradient in the electroplated nickel layer and in-use stiction of the cantilever beams.


1994 ◽  
Vol 363 ◽  
Author(s):  
T. S. Moss ◽  
W. J. Lackey ◽  
G. B. Freeman

AbstractThe CVD of the coatings in the B-Si-C-H-C1-Ar system was accomplished using a statistically designed experiment. The experimental design used five factor half-fraction factorial with a central composite design that was both rotatable and orthogonal. Deposits were thick and dense and were composed of B13C2 and β-SiC with compositions ranging from 0 to 100%. Response surfaces were generated using multivariate regression for unit cell volumes of B13C2 and β-SiC, %B13C2/%SiC in the coating, and the Si to B ratio in the deposit. These equations could then be used to examine the significant variables in the reaction, as well as for tailoring and optimizing the deposition process.


2015 ◽  
Vol 227 ◽  
pp. 243-246 ◽  
Author(s):  
Lidia Benea

High dispersed nano and micro particles as ceramics (SiC, TiC, WC, Al2O3), polymers (UHMWPE) or bioceramics (TiO2, CeO2, ZrO2) have been deposited by electrochemical method with nichel or cobalt on metallic substrate to obtain novel structured composites, cermet or hybrid coatings with specific properties to be used in industrial or biomedical applications. The industrial applications for metal matrix based nanocomposites are increasing and open a way to biocompatible coatings. electrodeposition is considered to be one of the most important techniques for producing nanocomposites and nanostructured surfaces. Electrodeposition is exceptionally versatile, so that new and exciting applications are still being invented. The paper presents some results regarding the electro-co-deposition of dispersed phases as ZrO2, CeO2, SiC, WC, TiC or polymeric dispersed phases as UHMWPE (ultra high molecular weight polyethylene) during cobalt or nickel electroplating process in view of obtaining new advanced functional surfaces with improved properties to corrosion or tribocorrosion systems.


1981 ◽  
Vol 103 (2) ◽  
pp. 294-307
Author(s):  
C. E. Lowell ◽  
S. M. Sidik ◽  
D. L. Deadmore

The effects of potential impurities, such as Na, K, Mg, Ca, and Cl, in coal-derived liquid fuels on accelerated corrosion of IN-100, U-700, IN-792, and Mar M-509 were investigated using a Mach 0.3 burner rig for times to 200 hr in 1 hr cycles. These impurities were injected in combination as aqueous solutions into the combustor. Other variables were time, temperature, and fuel-to-air ratio. The experimental matrix was a central composite fractional factorial design divided into blocks to allow modification of the design as data was gathered. The extent of corrosion was determined by metal consumption, τ.


Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1887 ◽  
Author(s):  
Thuan Van Tran ◽  
Duyen Thi Cam Nguyen ◽  
Hanh T. N. Le ◽  
Long Giang Bach ◽  
Dai-Viet N. Vo ◽  
...  

In this study, a minimum-run resolution IV and central composite design have been developed to optimize tetracycline removal efficiency over mesoporous carbon derived from the metal-organic framework MIL-53 (Fe) as a self-sacrificial template. Firstly, minimum-run resolution IV, powered by the Design–Expert program, was used as an efficient and reliable screening study for investigating a set of seven factors, these were: tetracycline concentration (A: 5–15 mg/g), dose of mesoporous carbons (MPC) (B: 0.05–0.15 g/L), initial pH level (C: 2–10), contact time (D: 1–3 h), temperature (E: 20–40 °C), shaking speed (F: 150–250 rpm), and Na+ ionic strength (G: 10–90 mM) at both low (−1) and high (+1) levels, for investigation of the data ranges. The 20-trial model was analyzed and assessed by Analysis of Variance (ANOVA) data, and diagnostic plots (e.g., the Pareto chart, and half-normal and normal probability plots). Based on minimum-run resolution IV, three factors, including tetracycline concentration (A), dose of MPC (B), and initial pH (C), were selected to carry out the optimization study using a central composite design. The proposed quadratic model was found to be statistically significant at the 95% confidence level due to a low P-value (<0.05), high R2 (0.9078), and the AP ratio (11.4), along with an abundance of diagnostic plots (3D response surfaces, Cook’s distance, Box-Cox, DFFITS, Leverage versus run, residuals versus runs, and actual versus predicted). Under response surface methodology-optimized conditions (e.g., tetracycline concentration of 1.9 mg/g, MPC dose of 0.15 g/L, and pH level of 3.9), the highest tetracycline removal efficiency via confirmation tests reached up to 98.0%–99.7%. Also, kinetic intraparticle diffusion and isotherm models were systematically studied to interpret how tetracycline molecules were absorbed on an MPC structure. In particular, the adsorption mechanisms including “electrostatic attraction” and “π–π interaction” were proposed.


2004 ◽  
Vol 50 (12) ◽  
pp. 1033-1040 ◽  
Author(s):  
Keisuke Ikehata ◽  
Michael A Pickard ◽  
Ian D Buchanan ◽  
Daniel W Smith

Optimum culture conditions for the batch production of extracellular peroxidase by Coprinus cinereus UAMH 4103 and Coprinus sp. UAMH 10067 were explored using 2 statistical experimental designs, including 2-level, 7-factor fractional factorial design and 2-factor central composite design. Of the 7 factors examined in the screening study, the concentrations of carbon (glucose) and nitrogen (peptone or casitone) sources showed significant effects on the peroxidase production by Coprinus sp. UAMH 10067. The optimum glucose and peptone concentrations were determined as 2.7% and 0.8% for Coprinus sp. UAMH 10067, and 2.9% and 1.4% for C. cinereus UAMH 4103, respectively. Under the optimized culture condition the maximum peroxidase activity achieved in this study was 34.5 U·mL–1 for Coprinus sp. UAMH 10067 and 68.0 U·mL–1 for C. cinereus UAMH 4103, more than 2-fold higher than the results of previous studies.Key words: Coprinus peroxidase, central composite design, fractional factorial design, production optimization, response surface.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Marinela Barbuta ◽  
Emanuela Marin ◽  
Sorin Mihai Cimpeanu ◽  
Gigel Paraschiv ◽  
Daniel Lepadatu ◽  
...  

The influence of coal fly ash and glass fiber waste on the tensile strength of cement concrete was studied using central composite design. Coal fly ash was used to replace 10% of the cement in the concrete mix. Glass fiber was added to improve the tensile properties of the concrete in different dosages and lengths. In total, 14 mixes were investigated, one only with 10% coal fly ash replacement of cement and the other thirteen were determined by the experimental design. Using analysis of variance, the order of importance of the variables was established for each property (flexural strength and split tensile strength). From the nonlinear response surfaces, it was found that higher values of flexural strength were obtained for fibers longer than 12 mm and at a dosage of 1-2%. For split tensile strength, higher values were obtained for fibers with a length of 19–28 mm and at a dosage of 1–1.5%.


2014 ◽  
Vol 97 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Heshmatollah Ebrahimi-Najafabadi ◽  
Riccardo Leardi ◽  
Mehdi Jalali-Heravi

Abstract This paper reviews the main concepts of experimental design applicable to the optimization of analytical chemistry techniques. The critical steps and tools for screening, including Plackett-Burman, factorial and fractional factorial designs, and response surface methodology such as central composite, Box-Behnken, and Doehlert designs, are discussed. Some useful routines are also presented for performing the procedures.


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