Anodizing Process Parameters Research Articles

THE EFFECT OF FLUORIDE AND INHIBITORS ON THE ANODIZED COPPER SURFACE

Two chemical solutions NH4F:H2O:C3H8O3(sol[Formula: see text] and NH4F:H2O:C2H6O2(sol[Formula: see text] with different fluoride ratios were used separately in an anodic process to study the morphological characteristics of the produced copper oxides. Glycerol and ethylene glycol were utilized as inhibitions to slow down the activity of fluoride ions. The rest of the anodization process parameters were constant. Scanning electron microscope (SEM) images showed the formation of Cu2O microcubes when sol1 was used. The utilization of sol2 produced octahedral Cu2O as well as cubes and spherical structures. The increase of NH4F in sol1 led to a reduction in the volumes of Cu2O microcubes, and in sol2, it produced incomplete octahedral Cu2O. Since ethylene glycol has a lower viscosity than glycerol, copper corrodes more quickly in the presence of the former than in the latter. The findings indicate that sol1 is experiencing a higher current flow than sol2. The relationship between current and time is semi-constant at low applied voltage, but the two curves behave differently when applying high voltage in the early stages.

Anodic Oxide Layers on Aluminum-Lithium Alloy

Al-Cu-Li alloys regained attention with Cu as the major addition and Li around 2 %wt. However, oxide blistering of is frequently found by the sulfuric acid anodizing of these alloys, which has been sometimes attributed to Li-rich precipitate dissolution or to thermomechanical stresses in the anodic oxide layer. In this work, anodic layer properties (composition, morphology, pitting resistance) were studied in dependence of anodizing process parameters. Blisters form by higher anodizing charges, independent of the applied current density and its density increases at lower temperatures, at which the anodizing efficiency is higher. Blistering cannot be associated to second phase precipitates, as their diameters (100-200 µm) are much larger than the precipitates size. The 45º-cracks at the mid section of the porous film are typical of compressive stresses perpendicular to the growth direction, indicating that blistering is possibly caused by a higher molar volume compared to other Al-Cu alloys.

Tape of the truth: Ta2O5 nanopore array formed under broad potential range and SERS potential after silver sputtering

The deposition of a plasmonic metal layer on a nanostructured oxide surface is one of the important methods of preparing a platform for surface-enhanced Raman scattering (SERS) measurements. In this contribution, we describe the formation of SERS substrates by the deposition of a silver layer on ordered a Ta2O5 nanopore array. The influence of various experimental anodization process parameters on the morphology of a Ta2O5 nanopore array was carefully studied. It was found that the formation of a Ta2O5 nanopore array is possible under a broad potential range (15–50 V) in a highly acidic solution containing F− ions. In some cases, the nanopore array structures were covered by an outer layer rich in F− and SO42− ions, which could easily be removed using adhesive tape or by sonication. The deposition of an Ag layer led to SERS activity. The optimal Ag layer thickness was specified based on SEM and DRS measurements. The SERS substrates formed exhibited high point-to-point, sample-to-sample and time durability.

An investigation on the adhesion of dual-scale micro-nano composite structure on the surface of aluminum

Adhesion is a crucial characteristic of hydrophobic surfaces that significantly impacts their practical applications. This paper proposes an innovative method for preparing a dual-scale micro-nano composite structure surface by combining mechanical ruling and anodic oxidation, which demonstrates great potential in enhancing hydrophobic surface properties. Through the analysis of the influence of micro-groove depth on the adhesion of hydrophobic surfaces, it has been discovered that micro-groove dimensions can be used to control surface adhesion while maintaining hydrophobicity, without complex chemical modifications. These findings present a promising approach for tailoring the properties of hydrophobic surfaces to suit specific applications. Compared with the single-scale micro-groove array structures, the surface roughness of the dual-scale micro-nano composite structures is significantly increased, and the contact angle of the water droplet is significantly increased. At the same time, the hydrophobicity and adhesion of the surface of the dual-scale micro-nano composite structures were analyzed. The results show that after anodizing, the contact angle of the dual-scale micro-nano composite structure surface increases, and the surface adhesion can be controlled by adjusting the structural parameters of the micro-groove and the anodizing process parameters, to ensure that the surface presents hydrophobic property while realizing the controllable adhesion of the hydrophobic surface. In this paper, dual-scale micro-nano composite structures fabricated by the composite method have achieved hydrophobic properties, and the surface adhesion can be effectively controlled by adjusting the processing parameters. This method has certain reference significance for the preparation of the controllable adhesive hydrophobic surface and lays a foundation for the further study of the controllable adhesive hydrophobic surface.

Fabrication and characterization of highly ordered nanotubes of anodic aluminum oxide

Investigated the electrochemical synthesis and characterized of a nanometer scale porous anodic aluminum oxide (AAO) membrane with a mean pore diameter about of 80-100 nm. The anodizing process done by varying the anodizing temperature from 20 °C to 25 °C. The membranes exhibit interesting properties such as controllable pore diameters, periodicity and density distribution. These properties can preselect by adjusting the controlling parameters of a temperature-controlled two-step anodization process. The surface features of the nanometer scale membrane such as pore density, pore diameter and interpore distance were quantified using scanning electron microscopy (SEM) and atomic force microscopy (AFM). SEM and AFM investigations revealed the presence of focal adhesion sites over the surface of the porous membranes. The positive outcomes of the study, indicates that AAO membranes can used for applications in the future.

Thermovision study on Alumina’s Ra v/s Ts for AIDHVACS to control COVID-19

The current study is the authors’ next work from the thermo vision perspective of real time single sun solar field performance infrared thermography (IRT) on commercial grade Alumina solar absorber surface coatings (SASCs) to recognize surface roughness (Ra) as one of the important production process parameters. In a previous study, it was investigated with IRT, and found that Ra<1.8 is favorable and hard anodized Alumina (HAAO) coatings exhibits better surface temperature (Ts) gain as compared to organic dyed non-HAAO coatings on Aluminum substrate, and are more stable in solar field for many years in open air environment without degrading their performance. It may be useful in better optimization of SASCs specifically for personal protective equipments (PPEs) sanitization and artificial intelligence (AI) driven heating ventilation air conditioning (HVAC) systems (AIDHVACS) design to control Covid-19 in current situations.The influence of Ra of few microns ∼ <15 µm on Alumina SASCs’ Ts gain is examined. The presented study shows that more than 1.05 mm thickness of substrate flat is necessary to develop good quality of alumina coating; Ra<1.8 µm is favorably expected to the extent of Ra value approaching as close as to nanoscale ∼ 5-500 nm; local surface temperature gained is depending upon local Ra profile as well as upon surface morphology in addition to the anodizing process parameters and other environmental factors. It suggests that the optimal surface profile should be designed as an integral to the production line processes. The substrate surface chemical composition may also change while processing due to surface contact with the processing tools, which may also result in altered solar field performance due to substrate altered material composition prior to hard anodizing process, as examined with X-ray fluorescence spectrometry (XRF) and ultraviolet–visible spectrophotometry (UV-VIS). The novelty is that other studies of surface roughness parameter is focused upon convective heat transfer inside tunnel or duct solar heat absorbers e.g. air heaters, whereas the authors have focused upon surface roughness of solar radiation receiving outer surface as an important commercial production process variable having effect upon conductive heat transfer in solar thermal power systems. The AIDHVACS needs machine learning and big data analysis as the need of the hour.

Development of photocatalytically active coating on cp-Ti by anodization

TiO2 has emerged as an excellent photocatalyst over the last few decades. TiO2 based photocatalysts find application in pollutant control, dye degradation, self-sterilizing coatings, self-cleaning materials, and so on. The present work focuses on the development of TiO2 coatings on a commercially pure titanium substrate (cp-Ti) with a nanotubular morphology by the process of anodization and aims to characterize the coatings formed and to study the effect of anodization process parameters (voltage, time and electrolyte concentration) on the morphology of the coatings. The anodization circuit consists of the cp-Ti sample as the anode, a platinum cathode, and an organic electrolyte with fluoride ions. The base electrolyte used in this work was a 9:1 by volume mixture of ethylene glycol and H2O. Experiments were conducted at combinations of 25 V, 30 V, and 40 V at 1 h and 1.5 h. The coated samples were heat-treated at 500 °C for 1 h in ambient conditions. The thickness of the coatings was measured, after which FESEM was performed to study the morphology of the coatings formed. The phases present in the coating were studied using XRD. The bandgap of the samples was measured using UV–Vis diffuse reflectance spectrometry. The FESEM images clearly showed the formation of a nanotubular coating. The diameters of the tubes increased with an increase in the voltage while the XRD results confirmed the presence of the anatase TiO2 phase.

A Review on Anodizing of Aerospace Aluminum Alloys for Corrosion Protection

Aluminum alloys used for aerospace applications provide good strength to weight ratio at a reasonable cost but exhibit only limited corrosion resistance. Therefore, a durable and effective corrosion protection system is required to fulfil structural integrity. Typically, an aerospace corrosion protection system consists of a multi-layered scheme employing an anodic oxide with good barrier properties and a porous surface, a corrosion inhibited organic primer, and an organic topcoat. The present review covers published research on the anodic oxide protection layer principles and requirements for aerospace application, the effect of the anodizing process parameters, as well as the importance of process steps taking place before and after anodizing. Moreover, the challenges of chromic acid anodizing (CAA) substitution are discussed and tartaric-sulfuric acid anodizing (TSA) is especially highlighted among the environmentally friendly alternatives.

The Effect of Anodizing Process Parameters on the Fatigue Life of 2024-T-351-Aluminium Alloy

Abstract The effect of an anticorrosive layer on the fatigue life of 2024-T-351-aluminium alloy has been studied in the present investigation. The fatigue tests were conducted on the aluminium alloy with and without anodizing to evaluate the fatigue life. The results indicate that the fatigue life of the anodized specimens is significantly shorter than that of untreated specimens. Further, experiments were conducted to evaluate the effect of the anodizing process parameters on the fatigue life of anodized specimens. These results show that the fatigue life of anodized aluminium alloy can be improved by controlling the anodizing process parameters such as process temperature, voltage, and time of immersion.

Influence of electrical parameters on morphology of nanostructured TiO2layers developed by electrochemical anodization

Ti6Al4V alloy micro rough surfaces with TiO 2 self-organized nanostructured layers were synthesized using electrochemical anodization in phosphate/fluoride electrolyte, at different end potentials (5V, 10V, 15V, and 20 V). The current – time characteristics were recorded, and the link between current evolution and the morphology of developing oxide layers was investigated. On flat surfaces of Ti6Al4V alloy we developed TiO 2 layers with different morphologies (random pores, nanopores of 25…50 nm, and highly organized nanotubes of 50…100 nm in diameter) depending on electrical parameters of anodization process. In our anodization cell, in optimized conditions, we are able to superimpose nanostructured oxide layers (nanotubular or nanoporous) over micro structured surfaces of titanium based materials used for biomedical implants.

Effect of anodizing on surface integrity of Grade 4 titanium for biomedical applications

Titanium-based alloys are widely used in the biomedical field due to various favourable material properties. These include low density, high corrosion resistance and good mechanical and biocompatible properties. Surface integrity descriptors such as topography, surface chemical composition and aesthetic appearance are important for adequate part performance. Various surface engineering treatments are routinely applied to obtain improved performance. The current investigation examines the effect of anodizing on the oxide layer thickness and composition, surface topography and aesthetic appearance. Anodizing is conducted on especially finished (Sa±13nm) Grade 4 titanium specimen at various voltages in a H2SO4 electrolyte. Surface analysis consisted of atomic force microscopy (AFM), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD) and UV spectrophotometry. The results show that highly-ordered oxide structures in partially anatase and rutile TiO2 substrates are readily achieved. Various interference colours are readily achieved with different anodizing process parameters. An increase in anodizing voltage leads to layer thickness growth, increased roughness and changes in surface phase composition. An increase in oxide layer thickness is coincident with an increase in surface roughness. Reference is made throughout the paper to the effect of the various surface integrity descriptors measured, on the perceived biomedical effect of implant performance of the specific descriptor in question based on published data.

Optimization of porous anodic alumina nanostructure for ultra high sensitive humidity sensor

In this report, we are going to present the development and optimization of high-performance porous alumina growth having a large surface to volume ratio for ultra-high sensitive humidity sensing. The control of the structure of pores, such as the diameter of pores, depth of porous layer, etc., has shown crucial implications for the sensitivity of sensor; and there are precisely fine-tuned with the anodization process parameters. The sensitivity of the prepared sensors reaches upto 793.02% while reported sensitivity for conventional capacitive humidity sensors is much less. Besides, the prepared sensor maintains its fair responsivity as well as sensitivity even up to 100 KHz unlike 10 KHz reported by other researchers so far; and it gives an added advantage for its applications where humidity measurement at high frequencies are required The samples are characterized by Field Emission Scanning Electron Microscopy (FESEM, FEI NNS 450) to support the results and impedance spectroscopy were employed for the electrical characterization of the sensor. An equivalent electrical circuit is obtained to represent the electrical performance at different humidity level and it is in good agreement with the observed results.

Anodic oxidation of the Ti–13Nb–13Zr alloy

This work presents the results of the investigations on the electropolishing and anodic oxidation of the Ti–13Nb–13Zr titanium alloy. Electropolishing was conducted in the solution containing ammonium fluoride and sulfuric acid, whereas the solution of phosphoric acid was used for anodic oxidation of the alloy. The influence of electropolishing and anodization process parameters on the texture (scanning electron microscopy (SEM)) and chemical composition (X-ray photoelectron spectroscopy (XPS)) of the surface layer was established. Electrochemical impedance spectroscopy in 5 % NaCl solution was used for the determination of the corrosion resistance of the alloy.

The Morphology of the Alumina Films Formed tn The Anodization Process of Aluminium in the Orthophosphoric Acid Solution. The Co-Fe Alloys Electrodeposition Into Obtained Alumina Pores

Abstract The optimal parameters of the anodic oxidation of aluminium in orthophosphoric acid solution was determined. In the pores of the obtained Al2O3 membranes with the ordered nanometric structure Co-Fe alloys were electrodeposited. The Al2O3 membranes were obtained in the two-stage anodic oxidation of aluminium in the 0.17 M H3PO4 solution in the temperature 1°C and at the electrolysis voltage 180 V. The influence of the anodizing process parameters on the thickness of oxide films and the diameter of pores and the distance between them in the alumina membranes were determined. The electrodeposition of Co-Fe alloys was carried out from sulphate baths containing sulphates (VI) of copper (II) and cobalt (II) of different composition, in potentiostatic conditions. The optimal electrolysis conditions were determined, where the cathodic deposits of the best quality were obtained. The conditions are: the electrolyte composition: 0.3 M Fe; 0.5 M Co; pH = 3, the potential: -0.760 V (vs. SHE1)).

Effects of Process Parameters on Hydrophobicity of Alumina Surfaces Fabricated by Hard Anodizing

In the present article, hard anodizing technique was used to prepare alumina films on aluminum alloy substrate. The change of the water contact angles on the surface of the as-anodized samples with the hard anodizing process parameters was studied. The wettability of the alumina films was reinforced by means of controlling the surface microstructure. The rough structures can trap a large amount of air and minimize the real contact area between surfaces and water droplets. The measurement of the wetting property showed that the water contact angle of the as-anodized samples increases from 82° to 130° with adjusting hard anodizing process parameters. In a word, the rough structure on the surface prepared by adjusting hard anodizing process parameters plays a vital role in the constructing of the stable hydrophobic surface on aluminum alloy.

Discoloration of Anodized AA6063 Aluminum Alloy

The effect of the anodizing process parameters and the influence of β′(Mg2Si) phase on the appearance of the anodized AA6063 aluminum alloy have been investigated. It was found that β′(Mg2Si) phase was preferentially oxidized at low anodizing voltages and the selective oxidation of β′(Mg2Si) phase resulted in the development of a rough alloy/film interface and the incorporation of silicon into the porous anodic film, which led to the discoloration of the anodized alloy.

Fabrication of nanoporous alumina by two-step anodization and studyof their structural properties

Anodic nanoporous alumina (NPA) is known to be a low cost material suitable for fabrication of templates for the growth of a variety of nanostructured materials, membranes and sensors. In this work, nanoporous alumina was prepared in 0.4 M oxalic acid by a two-step anodization process. The properties of nanoporous alumina film grown on aluminum foil were studied by atomic force microscopy (AFM), scanning electron microscopy (SEM) and optical microscopy. The microscopy investigations confirm the pore formation in the produced layers and the process of anodization allows consistent fabrication of nanoporous alumina. The effect of anodization process parameters on the size of the nanopores and the distance between them were studied and good agreement with published data was found. Hence a desired diameter of the pores and the distance between of it can be obtained by adjusting the electrolyte and oxidation voltage.

Fabrication of Nanoporous Alumina and Their Structural Characteristics Study Using SEM Image Processing and Analysis

Nanoporous anodic aluminum oxide (AAO) membranes were fabricated by a two-step anodization process. Quantitative structural characterization was carried out using scanning electron microscopy images of the fabricated anodized alumina. An algorithm based on mathematical morphology was developed to extract pore size distribution with average, minimum, and maximum pore diameter of the nanoporous alumina. This technique of obtaining quantitative data based on image analysis could be an efficient, unbiased, and reliable method and can be used to control the fabrication parameters of anodization process.

Modified TiO2 nanotube arrays (TNTAs): progressive strategies towards visible light responsive photoanode, a review

Since first introduced by Zwilling and co-workers in 1999, titania nanotube arrays (TNTAs) fabricated by simple electrochemical anodization method have attracted great interest due to their outstanding photoelectrochemical properties which render them the most promising candidate for many solar energy harvesting applications. In this contribution, the fabrication, properties, and applications of TiO2 nanotube arrays have been reviewed, with special focus on synthesis by anodization in fluoride-containing electrolytes. The effect of anodization process parameters such as electric potential, pH, anodization duration and electrolyte composition on the size, and morphology of TNTAs has been discussed in detail. Electronic property modification strategies of the wide band gap TNTAs to enhance the material responsiveness to visible light irradiation have also been reviewed. Modification strategies include nonmetal doping such as nitrogen, carbon, boron and sulfur; metal ion doping such as Fe, Zn, Zr and Cr; surface decoration with precious metal nanoparticles such as Pt, Ag, Au; and sensitization with CdS nanoparticles.

Influence of the anodization process conditions and the microstructure on the photothermal effect of porous silicon used as a therapeutic agent in cancer thermotherapy

Recently it has been reported that porous silicon (PSi) can be used as a therapeutic agent for cancer thermotherapy based on near-infrared (NIR) light irradiation. It is more important than anything else to develop a nanomaterial thermal coupling agent with a high photothermal effect in order to secure irreversible destruction of cancer cells and high selectivity between tumor tissues and healthy tissues in thermotherapy. In this paper we report the influence of anodization process parameters or the microstructure of PSi on the photothermal effect of PSi during NIR light irradiation. As the HF concentration, current density and etching time in the anodization process for PSi synthesis increases, the photothermal effect is enhanced since the pore size or the nanocrystallite size of the PSi decreases and the porosity of the PSi increases. The influence of quantum size effect on the photothermal effect in PSi is also discussed.