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The main purpose of this research was to determine the electrochemical behavior of the anodized AZ31 magnesium alloy with different current densities immersed under watered cementice paste. These results obtained by Tafel polarization curves and electrochemical impedance spectroscopy indicated a decrease of approximately 90% in the corrosion rate for the anodized AZ31 magnesium alloy with 25 mA/cm2 when compared to a non-anodized AZ31 magnesium alloy, evidencing the protection generated by the anodization process. In addition, by means of surface SEM and SEM of the cross section, it was possible to determine the growth of the anodized layer and the morphological changes caused by the electrochemical reaction on the surface of the anodized magnesium. These results obtained in this study concluded that the anodized AZ31 magnesium alloy anodized with a current density of 25 mA/cm2 presents a set of optimum properties to be implemented in highly corrosive industry process.

This study presents a detailed analysis of the wear presented in [8YSZ/α-Al2O3] multilayer coatings as a function of the bilayer number when exposed to a corro-erosive environment. In this study, the roughness and grain size decreased by 58 and 30%, respectively when comparing the 70 bilayers system with the 1 bilayer system. The surface factors and the higher bilayer number of the n = 70 system, influenced the 67.33% decrease in corrosion rate compared to the 1 bilayer system. Subsequently, by means of SEM and optical microscopy, the degradation of the coatings due to the impact of abrasive particles and the generation of oxides on the substrate surface caused by a partial delamination of the coating was evidenced. This wear was calculated by means of the mass loss after the corro-erosive test, obtaining a decrease of 55.25% for the system with 70 bilayers with respect to the system with 1 bilayer. The results obtained showed that the system with 70 bilayers presented the best set of electrochemical properties and lower wear in corrosive environments, which makes it the best candidate to be used as a protective coating.

The structural and electrochemical properties of the AISI 1045 steel coated with the following coatings, deposited using physical vapor deposition (PVD), were determined: titanium carbo-nitride (TiCN), chromium aluminum nitride (CrAlN) and boron carbo-nitride (BCN). A comparison of the x-ray diffraction results with the XPS results revealed that Ti-C-N, B-C-N and Cr-Al-N were the dominant constituents. The selected deposition conditions such as the nitrogen and carbon contents and activation energy were sufficient to form the coatings. The EIS results showed that CrAlN had the lowest porosity content, followed by TiCN and BCN. These data are linked to the polarization resistance of TiCN, CrAlN and BCN: Rp = 126.42x1010 ± 8.939x1011 KΩ cm2, Rp = 40.49x1010 ± 2.863x1011 KΩ cm2 and Rp = 23.10x1010 ± 1.633x1011 KΩ cm2, respectively; as well as the corrosion rate: 0.0049 ± 0.019 mm for CrAlN, 0.0123 ± 0.014 mm for TiCN and 0.0174 ± 0.010 mm for BCN. The AISI 1045 steel with the CrAlN coating had a higher corrosion resistance compared to the other coatings because Cr increased the electronegativity of CrAlN. These results indicate that the structural and electrochemical properties of the materials, the latter carried out in lubricated environments with simulated real service conditions, depend largely on the nature of the coating. Furthermore, these analyzed coatings can be used on components subjected to stresses with high wear in lubricated environments, specifically in the automotive and metalworking industries.

[CoN/AlN]n multilayer coatings with different bilayer numbers (n = 10, 20 and 30) were developed, showing an interesting evolution in the mechanical properties and tribological behavior. These coatings were deposited by pulsed laser deposition technique with a Nd: YAG laser (λ = 1064 nm) on Silicon (100) and AISI 302 steel substrates. The structural and chemical composition analysis was performed by (XRD) and (XPS), showing characteristic phases and the stoichiometry of AlN (111) and CoN (200) materials. The surface morphology by (AFM) presented a reduction in grain size and roughness as a function of the bilayer number. The mechanical evaluation found an increase of 40% in the hardness and 19.4% in the elastic modulus when comparing [CoN/AlN]30 to the cobalt nitride (CoN) single layer. The tribological analysis evidenced the values of 0.33 for the friction coefficient and 57 N for the critical load at which the adhesive failure of the coatings (LC2) appeared. The mechano-tribological results found in these transition metals-based multilayer nitrides open a possibility of future applications in mechanical devices that require high demands in service conditions due to the high mechanical performance observed in the [CoN/AlN]n multilayers.

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.

Steels are in constant contact with fluids that could generate corrosion regardless the application in which this steel is located. AISI-SAE 1045 like steels is widely used in different applications in engineering, even several of these parts made of this steel suffers wear processes. The synergy between corrosion and wear phenomena exacerbates the detriment of some physical properties of the material conducing it to a failure. A potential alternative to avoid this issue is to coat the material surface with an anticorrosive material, and among different techniques to produce coatings, physical vapor deposition ones are environmentally friendly, secure and with excellent properties on the final product. We report the production of coatings based on vanadium and carbon on AISI-SAE 1045 steels substrates varying some of the deposition parameters in a sputtering coatings machine. A 2 3 -factorial design of experiments was done with power applied to the vanadium target, power applied to the carbon target and temperature as active factors with two levels each one. A relevant effect of the power applied to V target and temperature on the anticorrosive properties of the coatings was found, thus increasing these factors levels always gives higher surface roughness and higher corrosion rates, this result together provides an important insight into the values that must be considered to achieve good anticorrosive properties on the material. Overall, these results indicate that with low V target power and room temperature, and high C target power the lowest corrosion rates and roughness of the group are achieved, both results agree.

316 stainless steel low carbon vacuum melted, used for surgical implants, has good corrosion resistance, but it is degraded in the body fluids presence, generating problems for the receiver, therefore it is necessary to apply coatings that improve their biocompatibility. In the current work hydroxyapatite and tricalcium beta phosphate coatings were applied on 316 stainless steel substrates, by the radio frequency magnetron sputtering technique, with a 2 m thickness for possible biomedical applications. The coatings characterization was performed, using scanning electron microscopy, found the Ca/P ratio of 1.639 for hydroxyapatite and 1.515 for phosphate, the friction coefficient was additionally evaluated by pin on disk tribometer, with a lower coefficient of beta tricalcium phosphate in relation to hydroxyapatite. The corrosion evaluation was carried out using the electrochemical polarization technique Tafel, in Ringer lactate, as simulated biological fluid. It was observed that the coatings improve the steel electrochemical behavior and between the two coatings the one that best behaves is the tricalcium beta phosphate, with a corrosion low rate.

In this research, we report on a comparative study of the corro-erosive properties of TaC and HfC individual coatings and (Ta70-Hf30-C) and (Ta30-Hf70-C) coatings. These were subjected to different impact angles of abrasive particles, corresponding with angles of 30°, 60° and 90°. It was determined that at 90°, a higher structural damage of the coatings obtained was presented. In addition, for all the systems, it was possible to conclude that the coating formed by (Ta30-Hf70-C) presented a roughness of approximately 7.11 nm, which influenced corrosive properties such as the corrosion potential and corrosion rate. Finally, it was possible to conclude that the (Ta30-Hf70-C) coating presented a higher resistance against corro-erosive environments. This was attributed to structural and mainly superficial factors, making this coating the best option to be implemented as a protective coating against highly aggressive environments in industry.

The aim of this work is to determinate the mechanical and tribological behavior of V-C-N coatings deposited on industrial steel substrates (AISI 8620), by using the carbon nitride coatings as a protective materials. The coatings were deposited on silicon (100) and steel substrates via magnetron sputtering system and by varying the applied bias voltage. The V-C-N coatings were characterized by x-ray diffraction (XRD), exhibiting the crystallographic orientations (111) FCC for V-C-N conjugated by VC (111) and VN (111) phases and (200) FCC for V-C-N conjugated by VC (200) and VN (200) phases. X-ray photoelectron spectroscopy (XPS) was used for determinate the chemical composition of metallic carbon nitride materials. Atomic force microcopy (AFM) was used for determination of the change in grain size and roughness with deposition parameters. By using nanoindentation, pin-on-disk, and scratch test curves, it was possible to estimate the hardness, friction coefficient and critical load of V-C-N surface material. Scanning electron microscopy (SEM) was performed to analyze morphological surfaces changes. Mechanical and tribological behavior in VCN/steel [8620] system, as function of bias voltage deposition, showed an increase of 58 % in the hardness, and reduction of 39% in the friction coefficient, indicating thus that the V-C-N coatings may be a promising material for industrial applications such as high-speed cutting (HSC) coated with VCN layer tested in machining processes against heat-treated steels AISI 8620.