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Anti-corrosive characterization of silicon, titanium, and zirconium oxide coatings deposited on aeronautical aluminum substrates via sol-gel

Bautista-Ruiz, Jorge | 2020-12

Currently, aircraft wings made of AA2024 T3 aluminum are primed between the aluminum substrate and the outer layer of paint to improve the material's adhesion and corrosion resistance. This type of primer contains chromates whose treatment generates highly toxic hexavalent chromium. This work studied the effect of applying dip-coating coatings of combined silicon, titanium, and zirconium oxides on AA2024 T3 aluminum substrates synthesized via sol-gel. The influence of the number of layers on the substrates anti-corrosive behavior in a 3% NaCl solution was studied using electrochemical impedance spectroscopy techniques and potentiodynamic polarization curves. The substrates corrosion resistance was found to improve substantially concerning the number of layers deposited.

Anticorrosive evaluation of copper-iron mixtures processed by powder metallurgy

Bautista-Ruiz, Jorge | 2021

Through the powder metallurgy process, copper and iron powders were mixed in the proportions Cu between 15% to 75% and iron from 25% to 85% that made up the binary material systems. Material systems were topographically characterized with atomic force microscopy. Corrosion tests were established using potentiodynamic polarization curves. The worn surfaces' characterization was carried out by means of a Confocal Scanning Laser Microscope to complement the study. It was determined that the mixtures' stability and behaviour have different behaviours depending on the evaluated system because the wear system caused, indicating that the phenomenon can be additive. The corrosive phenomenon is dominantly affected by the microstructure of the material. From the results found, it is possible to infer that the best systems evaluated by corrosive contain the highest percentage of copper content. The topographic variation indicates the transition from the active zone to the passive zone of the metal due to electrochemical reactions in the presence of aggressive media.

Biocompatibility of bismuth silicate coatings deposited on 316L stainless steel by sol-gel process

Bautista-Ruiz, Jorge | 2017-09-25

Bismuth silicate, (BSO) thin films have been fabricated by sol–gel process. The stable sol was synthesized by using bismuth nitrate (III) pentahydrate and tetraethyl orthosilicate (TEOS). The films were deposited by spin-coating at 1500 rpm on Stainless Steel 316L. The films were characterized by Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) besides the measured of the films thickness. This study aimed to evaluate the cell adhesion and cellular proliferation of osteoblast cells on BSO thin films and substrate 316L by MTT assay. It is concluded that the growth of osteoblasts is homogeneous in the surface of the coatings indicating that the medium offered by the films does not present active cytotoxicity and exceed in large number the level of cellular growth compared to Stainless Steel

Caracterización Anticorrosiva y de Biocompatibilidad en Recubrimientos Silicio-Titanio-Zirconio Sintetizados Vía Solgel y Depositados sobre Sustratos 316L

Bautista-Ruiz, Jorge | 2018-02

Se sintetizaron, los sistemas ternarios [Si/Ti/Zr: 10/70/20] y [Si/Ti/Zr: 10/20/70] vía sol-gel y se aplicaron sobre sustratos de acero inoxidable 316L mediante la técnica de inmersión. En los recubrimientos obtenidos se evaluó la respuesta anticorrosiva en una solución fisiológica simulada mediante curvas potenciodinámicas de polarización. Se estudió la biocompatibilidad celular de osteoblastos; la adhesión sustrato-recubrimiento; la topografía superficial, el espesor y la rugosidad en los recubrimientos. Los resultados de este estudio permiten establecer un alto grado de efectividad anticorrosiva y buena biocompatibilidad. Los recubrimientos sintetizados vía sol-gel establecen su potencialidad como barrera anticorrosiva en función del sistema ternario aplicado al sustrato de acero inoxidable 316L.

Caracterización de cerámicos inmersos en soluciones del sistema sio2 – tio2 – zro2 sintetizadas por el método sol-gel

Sanchez Molina, Jorge | 2017-05-30

Se presentan los resultados de la caracterización físico-cerámica, microquímica y estructural de muestras cerámicas de arcilla roja inmersas en soluciones de SiO2 – TiO2 – ZrO2 obtenidas por el método Sol-Gel utilizando tetraetil ortosilacato, tetrabutóxido de titanio y tetrabutóxido de zirconio. Las muestras cerámicas fueron elaboradas con polvos atomizados de arcilla roja, cocidas a 1000°C. Después de la cocción las cerámicas fueron inmersas en las soluciones en concentraciones en volumen 10/20/70: Si/Ti/Zr y 10/70/20: Si/Ti/Zr con tiempos de permanencia de 2, 4 y 6 minutos. Posterior al secado las muestras se trataron térmicamente a 600°C durante 60 minutos, a una velocidad de 2°C/min. Aspectos microquímicos y microestructurales de las muestras cocidas fueron establecidos mediante el uso de difracción de rayos X (DRX), espectroscopia de infrarrojo (FTIR) y detección de energías dispersivas de rayos X (EDX). Las propiedades tecnológicas evaluadas fueron la absorción de agua, densidad aparente y resistencia mecánica a la flexión. El estudio permitió establecer que las muestras inmersas en la solución 10/70/20: Si/Ti/Zr permiten incrementar la resistencia mecánica a la flexión. De igual manera se observó una ligera reducción del porcentaje de absorción de agua con este mismo tratamiento. El tratamiento con mayor presencia de zirconio no muestra cambios significativos respecto al patrón empleado (muestra sin inmersión)

Characterization of bismuth-silicate soles

Bautista-Ruiz, Jorge | 2019-11-29

The bismuth silicate compound was synthesized by the sol-gel method from bismuth nitrate pentahydrate and tetraethoxysilane, as precursors. The sol-gel method is attractive because the processes for obtaining oxides are developed at room temperature. In addition, it allows precise control over the composition, homogeneity, and deposition of coatings. The impact of bone-related diseases and trauma has increased significantly, in recent decades in developed and developing countries. There are materials such as bioactive glasses, especially silica compounds, which are called to play a very important role in this area, due to properties such as osteoconductivity, osteoproduction, and osteoinduction. For 20 years, the sol-gel method and the supramolecular chemistry of surfactants have been incorporated into the field of bioceramics, which allows the control, on a nanometric scale, of porosity in bioglasses. The sol-gel method has allowed obtaining bioactive materials with high surface area and high porosity. The study consisted of shaping soles by varying the molar concentrations of tetraethoxysilane and assessing the effect on aging, viscosity, determining the presence of specific functional groups and establishing the transformations that take place as a function of temperature. The results allowed characterizing each of the sol for possible application in bioglasses.

Characterization of clay material and rice husk from northeast Colombia

Sanchez Molina, Jorge | 2021-01

This research was to study materials from the region to use them industrially applying the circular economy concept. Clay Material and Rice Husk were evaluated in the manufacture of ceramic products. X-ray Diffraction and X-ray Fluorescence techniques were used to determine the raw materials' chemical and mineralogical composition. Thermal analysis techniques (TG and DTG) were used to complement the study. The XRD results showed an abundance of quartz. The results of the thermal analysis establish significant losses due to calcination. The thermal conductivity was also measured in ceramic specimens made from two types of pastes, one with 100% Clay Material and the other with a 5% substitution for Rice Husk. The results showed a decrease in thermal conductivity in the test tubes with the addition of Rice Husk. Consequently, the Rice Husk as a substitute for the Clay Material allows for ceramic production with thermal efficiency.

Characterization of the anticorrosive properties in bismuth-titanate films obtained by the sol-gel method

Bautista-Ruiz, Jorge | 2019-11-29

Sol-gel synthesis has been used since 1950 to prepare oxides. The method is attractive because the processes of obtaining the oxides are developed at room temperature; products with high purity and homogeneity are obtained, and allow the combination of several types of oxides: silicon, zirconium, titanium, aluminum, bismuth, and cerium. Sol-gel has been used to make ceramic composites with anticorrosive properties on stainless steel substrates. A class of stainless steel widely used in biomedical applications, especially in the treatment of fractures, 316L is its low economic cost relative to other materials such as titanium. Once the steel implant is inside the human body it comes into contact with body fluids that contain chloride ions. The fluid-implant interaction develops a corrosive process on the metal surface. The corrosive products of iron diffuse in the body causing tissue damage. As a possible solution to this problem, the objective of the investigation was to obtain a bismuth-titanium oxide using the sol-gel method and apply it on 316L stainless steel substrates. Bismuth nitrate pentahydrate and titanium tetrabutoxide were used as precursors. The anticorrosive response was evaluated in a simulated physiological solution, Ringer's solution, by electrochemical impedance spectroscopy and potentiodynamic polarization curves. It is concluded that the coatings function as a corrosion barrier preventing the chloride ions Ringer's solution reach the metal surface.

Characterization of the tribological properties of bismuth-titanate coatings synthesized by sol-gel on 316L stainless steel substrates

Bautista-Ruiz, Jorge | 2019

The objective of this investigation was to obtain ceramic coatings of bismuth titanate by Sol-gel synthesis on 316L stainless steel substrates using bismuth nitrate pentahydrate (III) and titanium tetrabutoxide as precursors. The characterization focused on determining wear rates, coefficients of friction, adhesion, nano-hardness, and thickness of the coatings, depending on the concentration of the precursors, the speed of rotation and the number of layers. It is concluded that the sol presents favorable conditions for their potential application as coatings on metallic substrates

Determination of the efficiency of hafnium carbide and tantalum carbide coatings deposited on exchange membrane fuel cells

Ruiz Madera, C | 2021-10

Effect of forming technique BixSiyOz coatings obtained by solgel and supported on 316L stainless steel

Bautista-Ruiz, Jorge | 2016-02-12

BixSiyOz type coatings via sol-gel synthesized from bismuth nitrate pentahydrate, and tetraethyl orthosilicate as precursors; glacial acetic acid and 2-ethoxyethanol as solvents, and ethanolamine as complexing. The coatings were supported on AISI 316L stainless steel substrate through dip-coating and spin-coating techniques. The study showed that the spin-coating technique is efficient than dip-coating because it allows more dense and homogeneous films.

Effect of layer thickness on anticorrosive performance of 316L steel coated with bismuth-titanium films

GARZÓN AGUDELO, PEDRO | 2021-05

. Bismuth and titanium are elements with remarkable properties and applications in technological developments and in the field of biomedical engineering. The sol-gel method was used to form a bismuth-titanium system, which allowed to establish if it was possible to obtain films with anticorrosive properties on 316L stainless steel. The anticorrosive response was evaluated by means of Tafel curves, defining the parameters to obtain thin and functional films with good tribological properties. The coatings were obtained by the spin coating technique, varying the spin speeds from 3000 rpm to 5000 rpm with monolayer and bilayer systems. More positive values of corrosion potential were obtained when the steel is coated by the films, which implies a lower propensity to corrosion in saline medium, lower corrosion rates and higher potentials are reported for films with higher titanium content, likewise, better efficiency of the films with respect to the uncoated substrate is presented, the higher the titanium content and a strong influence between the calculated efficiencies and the centrifugation speeds is not observed

Effect of Temperature on the Tribological Properties of Hafnium Carbonitrides Coatings

Aperador Chaparro, William Arnulfo | 2023-04-21

For industrial processes in which refractory metals are necessary, hafnium carbonitride exhibits excellent performance due to its high thermal conductivity and resistance to oxidation. In this study, hafnium carbonitride was deposited on Inconel 718 steel and silicon (100) substrates. The objective was to characterize the wear properties as a function of temperature. The layers were deposited by physical vapor deposition (PVD) in an R.F. sputtering magnetron system from carbon targets and high-purity hafnium (99.99%). The wear tests were carried out at temperatures of 100 ◦C, 200 ◦C, 400 ◦C, and 800 ◦C in non-lubricated conditions. The coefficient of friction (COF) was recorded in situ. The heat treatment temperature on coatings is essential in determining anti-wear efficiency. It was determined that high temperatures (800 ◦C) improve resistance to wear. High-resolution XPS spectra were used to detect the chemical states of Hf 4f5/2 and Hf 4f7/2. The 4f5/2 and 4f7/2 binding energy indicates the presence of HfN and HfC. Using the TEM technique in bright field mode allowed us to know the orientation, crystallographic structure and interplanar distances of the HfCN. The topography of the coatings, by AFM, shows uniform grains and very small characteristics that determine the low surface roughness value. The SEM image of the cross-section of the HfCN coating shows homogeneity of the layer; no cracks or deformations are observed.

Effect of the addition of rice husk in technological properties of materials for the manufacture of ceramic

Bautista-Ruiz, Jorge | 2021-06

In this study, the rice husk discarded by the agro-industrial rice company in the department of Norte de Santander (Colombia) was used to replace clay material in the manufacture of tile-type ceramics. The materials were used to make test specimens with the presence of 5%, 10%, 15%, and 20% (weight) of scale and with three different types of grain size (1180 µm, 180 µm, and 75 µm mesh through). The specimens were molded using the extrusion technique. The shaped materials were subjected to different firing temperatures (900 °C, 1000 °C, 1100 °C, 1150 °C, and 1200 °C) to establish correlations between the microstructure/topography of the material and some of the technological properties of the ceramic such as the mechanical resistance to bending, resistance to deep abrasion, percentage of water absorption and linear drying/cooking shrinkage. The results show that proportions higher than 10% of rice husk do not obtain ceramics with ideal technological properties for use as pavement or coating. The best results were obtained when the husk was used at 5% and 180 µm mesh through grain size. The X-ray diffraction analysis of the cooked samples shows significant changes in the proportion of phases formed (test tubes with and without substitution of clay material) as the temperature increases.

Effect of the application technique on the colorimetric coordinates for a ceramic enamel

Bautista-Ruiz, Jorge | 2020-12

In ceramic tiles production processes for ornamental purposes, the industry uses enamel as raw materials that support the pigments that give coloration and tonal constancy in a glassy matrix. These parameters are of great interest in the acceptance of the final product by the consumer. Due to the increasing number of complaints related to variations in tone in ceramic enamel of the tiles produced by a ceramic company in northeastern Colombia, this work studied the enamel approval methodology's effect on the final tone of the ceramic pieces. A ceramic enamel was prepared and applied by the enameling pad technique on tiles manufactured by dry pressing. By applying the spectrophotocolorimetric technique, the colorimetric parameters were determined. The Tukey test's statistical results did not show statistical significance in the tile samples' tonal variation.

Effect of the number of layers on surface topography of bismuth-titanium coatings

Garzón, P | 2019-11-29

The objective of this research is to perform a topographic characterization by atomic force microscopy of the surface of bismuth titanate (Bi/Ti) coatings varying the number of layers deposited on the substrates, considering that there were not results of reported studies in which these precursors were used. It is important to analyze the surface behavior of these coatings as a first phase of future researches to establish the viability of possible uses and applications in biomedical industry. The films were synthesized by the sol-gel method from bismuth nitrate pentahydrate and titanium tetrabutoxide. Subsequently, by means of the spin- coating technique, the coatings were deposited on 316L stainless steel in monolayer and bi- layer, as this type of steel has been widely used for medical applications due to its good compatibility. The roughness values of each of the coatings were also determined. It is concluded that there is a relationship between the topography of the surface and the roughness values of the films with respect to the concentration of the precursors, the number and the speed of centrifugation of the layers deposited on the substrate. High concentrations of titanium tetrabutoxide effect on the good densification characteristics of the coatings.

Evaluation of mechanical wear in bismuth-titanium coatings synthesized by the sol-gel method and applied on 316 L stainless steel substrates

Aperador Chaparro, William Arnulfo | 2019-11

Steels are part of the basic equipment of most of the industrial framework, including very diverse sectors such as the oil, chemical and automotive industries. However, steels are susceptible to wear phenomena limiting their life in use and losing efficiency in the applications to which it is intended leading to a technological and economic problem. In mechanical systems, lubrication requires effective strategies to ensure that the increase in critical contact voltages does not cause material failure during operation. Although there are different ways to avoid the wear of steel parts, the development of material technology has allowed the manufacture of new alloys with anti-wear properties. Replacing steels with other higher cost materials is very unfeasible. For this reason, one of the alternatives of greatest interest to reduce wear is based on the surface modification of the metal through the use of coatings. The sol-gel method allows the manufacture of coatings on steel parts to reduce wear. The objective of this work was to manufacture, using sol-gel, bismuth-titanium coatings on 316 L stainless steel substrates in order to analyze the mechanical wear of the system and evaluate its wear rates and friction coefficients. The study focused on determining the effect of precursor concentration on performance as a film to reduce wear. It was determined that the friction coefficients show significant variations due to adhesive wear processes. With respect to wear, it is concluded that the coatings offer substrate protection by indicating wear rates lower than those reported for 316 L stainless steel substrates without coating.

Evaluation of micro-abrasion-corrosion on SiO2-TiO2-ZrO2 coatings synthesized by the sol-gel method

Bautista-Ruiz, Jorge | 2016-02-12

The medical science and the engineering, work to improve the materials used in the manufacture of joint implants, since they have a direct impact on the quality of people life. The surgical interventions are increasing worldwide with a high probability of a second or even a third intervention. Around these circumstances, it was evaluated the behaviour against microabrasion-corrosion phenomena on SiO2 TiO2 ZrO2 coatings, synthesized by the sol-gel method with concentration of the Si/Ti/Zr precursors: 10/70/20 and 10/20/70. The coatings were deposited on AISI 316 LVM stainless steel substrates. The morphological characterization of the wear was made by AFM techniques. It was observed that the coatings with higher levels of titanium have a good response to the phenomena of microabrasion-corrosion.

Evaluation of the wear-corrosion process in beta-tricalcium(β-TCP) films obtained by physical vapor deposition (PVD)

Bautista-Ruiz, Jorge | 2019

A simultaneous evaluation was done of the wear-corrosion of the coatings of beta-tricalcium phosphate on titanium (Ti) substrate deposits obtained by the magnetron sputtering technique. The characterization was developed by a tribometer system coupled to an electrochemical cell. This system allows the combination of corrosion and friction tests between the surface of the coating and the spherical bone pin. The synergy of the two wear phenomena was characterized, which were monitored by means of the electrochemical response as a function of the value of the friction coefficient. It was determined that the system generates a gradual film accumulation process, followed by an instantaneous loss after a critical period. Additionally, it is concluded that the increase in the coefficient of friction is not immediately followed by the increase in wear rate

Geopolymers Based on a Mixture of Steel Slag and Fly Ash, Activated with Rice Husks and Reinforced with Guadua angustifolia Fibers

Aperador Chaparro, William Arnulfo | 2023-08-15

At present, the conservation of the environment represents an objective that everyone wants to achieve. The construction industry has influenced the advancement of alternative materials that comply with sustainable development. In this article, reinforced concrete was obtained by mixing 80% blast furnace slag and 20% fly ash. These concentrations were chosen because they provide the lowest porosity in the cementitious matrix. Rice husk ash was used as an activator. Guadua angustifolia fibers were used to evaluate the mechanical performance of the concrete. The composition of the raw material was determined by X-ray fluorescence, the microstructure of the fibers by AFM, and the SEM technique was used to determine the surface characteristics of guadua fibers and concrete mixes. The structural characterization using XRD, the structure of the molecules of the guadua fiber, and the composition of the mixture’s molecular mixtures were determined by FTIR spectroscopy. Its properties, such as tensile strength and flexural strength, were analyzed. The results indicated that the concrete with the addition of Guadua angustifolia fibers. The results indicated that the concrete with the addition of guadua angustifolia fibers showed the best mechanical behavior. Tensile strength was optimized, establishing values of 2.68 MPa for unreinforced concrete and up to 3.12 MPa for fiber-reinforced concrete. The flexural strength values increase at ages after 28 days due to the pozzolanic reaction generated. Values of 2.8 MPa were obtained for concrete without fiber and 3.5 MPa for concrete reinforced with guadua angustifolia fiber.