Superficial Properties Research Articles

Lung Ultrasound Surface Wave Elastography: A Pilot Clinical Study.

A lung ultrasound surface wave elastography (LUSWE) technique is developed to measure superficial lung tissue elastic properties. The purpose of this paper was to translate LUSWE into clinical studies for assessing patients with interstitial lung disease (ILD) and present the pilot data from lung measurements on 10 healthy subjects and 10 patients with ILD. ILD includes multiple lung disorders in which the lung tissue is distorted and stiffened by tissue fibrosis. Chest radiography and computed tomography are the most commonly used techniques for assessing lung disease, but they are associated with radiation and cannot directly measure lung elastic properties. LUSWE provides a noninvasive and nonionizing technique to measure the elastic properties of superficial lung tissue. LUSWE was used to measure regions of both lungs through six intercostal spaces for patients and healthy subjects. The data are presented as wave speed at 100, 150, and 200 Hz at the six intercostal spaces. As an example, the surface wave speeds are, respectively, 1.88 ± 0.11 m/s at 100 Hz, 2.74 ± 0.26 m/s at 150 Hz, and 3.62 ± 0.13 m/s at 200 Hz for a healthy subject in the upper right lung; this is in comparison to measurements from an ILD patient of 3.3 ± 0.37 m/s at 100 Hz, 4.38 ± 0.33 m/s at 150 Hz, and 5.24 ± 0.44 m/s at 200 Hz in the same lung space. Significant differences in wave speed between healthy subjects and ILD patients were found. LUSWE is a safe and noninvasive technique which may be useful for assessing ILD.

Superficial physicochemical properties of polyurethane biomaterials as osteogenic regulators in human mesenchymal stem cells fates

All of the cells’ interactions are done through their surfaces. Evaluation of surface physicochemical scaffolds along with other factors is important and determines the fate of stem cells. In this work, biodegradable and biocompatible polyester/polyether based polyurethanes (PUs) were synthesized by polycaprolactone diol (PCL) and poly (tetra methylene ether) glycol (PTMEG) as the soft segment. To assess better the impact of surface parameters such as stiffness and roughness effects on osteogenic differentiation of the human mesenchymal stem cell (hMSC), the dimension effect of substrates was eliminated and two-dimensional membranes were produced by synthesized polyurethane. Surface and bulk properties of prepared 2D membranes such as surface chemistry, roughness, stiffness and tensile behavior were evaluated by Attenuated total reflectance Fourier transform infrared (ATR-FTIR), atomic force microscopy (AFM) and tensile behavior. The prepared 2D PU films had suitable hydrophilicity, biodegradability, water absorption, surface roughness and bulk strength. The hMSCs showed greater osteogenesis expression in PU substrates with more roughness and stiffness than others. The results demonstrated that surface parameters along with other differentiation cues have a synergistic effect on stem cells fates.

Water Is and Is Not H2O

The Twin Earth thought experiment invites us to consider a liquid that has all of the superficial properties associated with water (clear, potable, etc.) but has entirely different deeper causal properties (composed of “XYZ” rather than of H2O). Although this thought experiment was originally introduced to illuminate questions in the theory of reference, it has also played a crucial role in empirically informed debates within the philosophy of psychology about people’s ordinary natural kind concepts. Those debates have sought to accommodate an apparent fact about ordinary people’s judgments: Intuitively, the Twin Earth liquid is not water. We present results from four experiments showing that people do not, in fact, have this intuition. Instead, people tend to have the intuition that there is a sense in which the liquid is not water but also a sense in which it is water. We explore the implications of this finding for debates about theories of natural kind concepts, arguing that it supports views positing two distinct criteria for membership in natural kind categories – one based on deeper causal properties, the other based on superficial, observable properties.

Simultaneous ageing and plasma nitriding of grade 300 maraging steel: How working pressure determines the effective nitrogen diffusion into narrow cavities

Maraging steels combine excellent mechanical properties at medium-high temperatures with good fracture toughness, but they usually require the aid of thermochemical treatments to enhance superficial properties such as resistance to abrasive wear and corrosion resistance. In particular, plasma nitriding, due to its duration and temperature, which are compatible with the age-hardening cycles of maraging steels, permits the realization of both processes simultaneously.In this work, simultaneous ageing and arc-activated plasma nitriding of maraging steel grade 300 were studied as a function of the working pressure of the gases (N2 and Ar) present in the vacuum reactor chamber. In addition, the influence of the operating pressure was established by analysing the capacity of the plasma to penetrate in 2.5mm in diameter blind holes.In-depth chemical composition, hardness and micro-hardness profiles, X-Ray diffraction, roughness, tribological characterization and corrosion tests were carried out to compare maraging steel samples treated in one simultaneous plasma nitriding and ageing process and in two-step processes. Metallographic tests and nanoindentation measurements were performed to study how the plasma penetrates and diffuses into the blind holes and how the nitride case layer thickness formed at the inner surfaces of the holes changes as a function of the distance to the surface for various working pressures.

N and F Codoped TiO2 Thin Films on Stainless Steel for Photoelectrocatalytic Removal of Cyanide Ions in Aqueous Solutions

N-F codoped TiO2 films were immobilized on stainless steel sheets through a combined approach involving a dip-coating technique and a hydrothermal treatment, followed by calcination at 400°C in the presence of air. Photocatalyst characterization was conducted using XRD, Raman and UV-VIS spectroscopy as well as SEM. The films were tested in a three-electrode cell for the photoelectrocatalytic degradation of CN-containing compounds. The results showed that the increase in the degradation rate of CN-containing compounds is both influenced by a synergistic effect of the doping agents and strongly dependent on the concentration of CN-containing compounds in the solution. Nitrogen contributed to the enhanced photoactivity under visible light due to the generation of localized states within the band gap of TiO2, whereas the presence of fluoride improved the superficial properties of the film, which resulted in higher amounts of CN-containing compounds that were degraded by direct charge transfer through the photogenerated holes.

New methodology for mechanical characterization of human superficial facial tissue anisotropic behaviour in vivo

Mechanical characterization of human superficial facial tissue has important applications in biomedical science, computer assisted forensics, graphics, and consumer goods development. Specifically, the latter may include facial hair removal devices. Predictive accuracy of numerical models and their ability to elucidate biomechanically relevant questions depends on the acquisition of experimental data and mechanical tissue behavior representation. Anisotropic viscoelastic behavioral characterization of human facial tissue, deformed in vivo with finite strain, however, is sparse.Employing an experimental-numerical approach, a procedure is presented to evaluate multidirectional tensile properties of superficial tissue layers of the face in vivo. Specifically, in addition to stress relaxation, displacement-controlled multi-step ramp-and-hold protocols were performed to separate elastic from inelastic properties. For numerical representation, an anisotropic hyperelastic material model in conjunction with a time domain linear viscoelasticity formulation with Prony series was employed. Model parameters were inversely derived, employing finite element models, using multi-criteria optimization.The methodology provides insight into mechanical superficial facial tissue properties. Experimental data shows pronounced anisotropy, especially with large strain. The stress relaxation rate does not depend on the loading direction, but is strain-dependent. Preconditioning eliminates equilibrium hysteresis effects and leads to stress-strain repeatability. In the preconditioned state tissue stiffness and hysteresis insensitivity to strain rate in the applied range is evident.The employed material model fits the nonlinear anisotropic elastic results and the viscoelasticity model reasonably reproduces time-dependent results. Inversely deduced maximum anisotropic long-term shear modulus of linear elasticity is G∞,maxaniso=2.43kPa and instantaneous initial shear modulus at an applied rate of ramp loading is G0,maxaniso=15.38kPa.Derived mechanical model parameters constitute a basis for complex skin interaction simulation.

Mechanisms of change of superficial properties of polymeric materials in discharge plasma

In work analytical expressions for assessment of the tribochemical changes and definition of the most effective direction of regulation of contact interactions are received. These results can be used for the analysis of experimental data at a research of mechanisms of change of polymeric materials superficial properties.

Slug Flow Simulation, A Way to Improve Air Scouring of Water Mains?

When transporting gas and liquid in the same pipe, waves might become unstable and grow until they bridge the entire pipe cross-section. This flow pattern is called slug flow, and consists of alternating pockets of gas and liquid plugs propagating at high speed through the pipeline. Simulation of slug flow is a topic widely investigated in the oil and gas industry, where slug flow is not desired due to its chaotic nature and increased wall shear stress. The method for cleaning water mains known as air scouring uses this increase of wall shear stress in order to get high efficiency in particle, scale, biofilm and tubercle removal. This is believed to be more effective than unidirectional flushing and to use up to 40% less water. The efficiency of the cleaning depends on the characteristics of the slugs such as length, velocity and frequency, which are determined by amongst others the water and air superficial velocities, interface friction, fluid properties and pipe properties. The use of slug flow simulation may help to obtain the optimal slug flow characteristics for every sequences of air scouring in order to save both time and water, and ensure the most efficient cleaning of the water mains.Sluggit is a computational slug flow simulator developed at NTNU for the oil and gas industry. The objective of our work was to validate its predictions for slug flow characteristics within water distribution systems. Slug flow is generated with tap-water and compressed air in a 50 m long PVC pipe with 150 mm of internal diameter. Water distribution system conditions, such as pressure and exit diameter are reproduced. The slug characteristics from the experiments are recorded, and compared with the predictions of Sluggit.

DETERMINATION OF SOME PHYSICAL AND CHEMICAL PROPERTIES OF PECTIN SUBSTANCES FROM THE SOLVENT CAKE OF TAGETES PATULA L. INFLORESCENCES

Big molecular weight conditions are responsible for some properties, which are absent in low molecular compounds. Therefore, its determination allows revealing of some physical and technological properties of biopolymers and prediction of the possibility of their practical application. The aim of this work was to determine an average molar weight, to study the superficial properties at the border of “solution-air” phases, and to establish an isoelectric spot of water solutions of pectin substances (PS), isolated from a solvent cake of Tagetes patula inflorescences. Materials and methods. Polysaccharide complexes were isolated from the solvent cake of Tagetes patula inflorescences of Carmen species which was left after a raw material extraction with ethanol 40% with the method of Kochetkov and M. Sinnera. The time of water and PS solutions flow out was measured by the use of a capillary Ostwald viscosimeter; different types of viscosity were calculated. The density of solutions was determined by using a picnometric method, however due to the closeness of density of the analyzed solutions and water, they were not considered in the calculation of the relative viscosity. Series of solutions with 0.01 to 0.5% concentrations were prepared from 1% PS water solutions to determine a surface activity. Monometric liquid tension variations were set in Rehbinder’s apparatus in the moment of an air bubble appearance on the surface of PS solution. Isoelectric spot (IES) of PS was determined in acetate buffer solution with pH within 3.2 to 6.2 by using the viscometer method. Results and discussion. Fractioning of the obtained polysaccharide complexes showed that efficiency of the pectin substances amounted to 2.2%. Calculation shows that an average molar weight of PS amounted to 45272 g/mol. About the degree of interaction between macromolecules of polymer and solvent, structural properties of macromolecule, the degree of its branching can be judged by the value of Huggins test. The value was found to be 1.46, which proves the low solubility of PS in water. Apparently, a biopolymer chain has been branched which worsen the solubility of macromolecules and further may promote the formation of gel condition. PS, isolated from the solvent cake of Tagetes patula, belong to the group of the surface active substances. Due to a big cross section of a molecule (S) and the high average molar weight, (45272 g/mol) molecules occupy a big volume at the surface of phase separation. We have established that macromolecule is in the isoelectric state at pH = 4.7. Conclusion. In the result of the studies using viscometer method, we have determined a molar weight of PS equal to 45272 g/mol. Huggins constant (1.46) which is connected to a low solubility of PS in water has been determined. We have established that PS, isolated from the solvent cake of Tagetes patula, are surface active. We have shown that PS macromolecule is in the state of polyamphion at pH = 4.7.

One-step hydrothermal synthesis of LaFeO3 perovskite for methane steam reforming

This work describes the synthesis of LaFeO3 oxide, using a one-step hydrothermal synthesis route, to obtain a solid with useful superficial, morphological and textural properties for applications in steam methane reforming reaction. The synthesis process starts from the corresponding metal nitrates of lanthanum and iron dissolved in deionized water in well-defined concentration, and the dissolution of KOH as mineralizing agent. The reaction is developed in a Teflon-lined stainless steel autoclave at 300 °C for 14 days. The composition and surface area were determined with X-ray fluorescence and nitrogen adsorption isotherms, confirming the basic stoichiometry of oxide and a high active area. The crystalline structure was evaluated with X-ray diffraction analysis, showing a pure orthorhombic perovskite phase. Temperature programmed reduction results show the development of three single steps at different temperatures, kinetically detectable and related with reduction of component oxides. Scanning and transmission electron microscopy results, showed a remarkable degree of crystallization, favoring a specific morphology as result of the low consolidation temperature of the perovskite phase. The catalytic test, analyzed by means of steam methane reforming action, performed along 240 h on stream, reveals a light deactivation rate, decreasing progressively 7.1 % until 60 % of methane conversion, indicating the improved morphological and surface characteristics of solid for potential applications.

Modification of microstructure and superficial properties of A356 and A356/10%SiCp by Selective Laser Surface Melting (SLSM)

Abstract Selective Laser Surface Melting (SLSM) and Laser Surface Melting (LSM) have been successfully applied in surface modification of A356 alloy and aluminium matrix composites reinforced with SiC particles (A356/10%SiCp). Refined microstructures were obtained for both treatments: SLSM allowed the refinement of the eutectic microconstituent, whereas in LSM all the phases were melted and resolidified. Vickers micro-hardness and nanoindentation tests confirmed an improvement in the mechanical properties; SLSM causes the highest hardening effect in the resolidified eutectic Al-Si branches while, simultaneously, eliminates porosity and brittle phases. In composites, an enhancement in bonding and distribution of SiCp was also obtained without Al 4 C 3 formation.

Instabilities due to turbulence through inlet jet in plunging jet bubble column

Bubble columns, where the liquid is in the continuous phase and the gas phase is on the form of dispersed bubbles, are widely utilised in many industrial applications. When designing these bubble columns it is important to be able to predict the conditions that mark the transition from homogeneous (bubbly) to heterogeneous (churn-turbulent) flow. The transition is a function of many variables, including: liquid and gas superficial velocities, bubble diameter, and liquid and gas physical properties. Linear stability analysis (LSA) has been successfully applied by many researchers to determine the gas volume fraction at which the instability takes place; and correspondingly a one dimensional stability factor, f1, has been proposed (see for example Joshi et al. (2001)). Briefly, the LSA analysis utilises the velocity fluctuations of both the dispersed and continuous phases associated with the specific energy dissipation rate of the two phase mixture. Typically, the specific energy dissipation rate is correlated with the density of the bed. The previous analysis, however, does not consider the energy input which associated with the turbulence intensity (velocity fluctuations) of the incoming liquid stream. Usually, this component can be ignored in sparged bubble columns because its magnitude is relatively small and it also decays in the axial direction. In plunging liquid jet bubble columns the liquid is introduced as a high speed jet that entrains gas which is then broken into fine bubbles in the Mixing Zone. The bubby mixture then passes into the Two Phase Flow Zone where instabilities can be generated. The Mixing Zone is a region of high energy dissipation resulting in relatively large liquid velocity fluctuations, which can directly influence the instability of the Two Phase Flow Zone.In this study the existing linear stability analysis is modified to include the influence of inlet liquid velocity fluctuations on the stability parameter, f1. The modified theory is applied to the previous work of Evans (1990) for a plunging liquid jet bubble column to determine the critical gas volume fraction at which transition takes place in the Two Phase Flow Zone. In order to apply the model, drift-flux analysis has been used to obtain bubble diameter as a function of gas and liquid superficial velocities, and computational fluid dynamics has been utilised to quantify the velocity fluctuations of the liquid exiting the Mixing Zone.

A functional effect of the superficial mechanical properties of articular cartilage as a load bearing system in a sliding condition

Abstract The structure and composition of articular cartilage show depth-wise inhomogeneity and anisotropy. In particular, the dense collagen network covers and reinforces the superficial tangential zone of the tissue. It is thought that this peculiar structure offers the excellent tribological property of articular cartilage. The purpose of this study was to investigate the functionality of the superficial tangential zone (STZ) of articular cartilage as a load bearing system. The 2-dimensional finite element (FE) model was accepted for sliding configuration with sufficient extent of sliding distance. The standard model as a control was carried from our previous study, which included depth-dependent Young׳s modulus of the solid phase, fiber reinforcement with strain-dependency and permeability with compaction effect. The mechanical property of the superficial layer was modified for a parametric study of its functionality. According to research results in the past, the tangential stiffness of the fiber reinforcement of the STZ model was enhanced, and the following anisotropic permeability was also modified. The stationary contact condition and the migrating contact condition were examined to compare the effect of the superficial tangential layer. The result showed that the significant reduction of friction coefficient was found in migrating contact condition of the STZ model. In the observation of field output of FE analysis, the contacting surface formed a thin low permeability layer, which would enable the high fluid pressure and the low fluid flow at the same time. It seemed that the stiffening of the fiber reinforcement of the superficial layer promoted the formation of the low permeability layer. Beyond the effectivity of the fiber reinforcement of biphasic matrix on the interstitial fluid pressurization, the findings of this study indicated that the compaction effect on the permeability would involve a quite complex phenomenon in long term migrating contact sliding.

Molten Corium–Concrete Interaction: Investigation of convective heat transfer in a pool with gas sparging

During a severe accident in a Pressurized Water Reactor, corium may fall in the reactor pit and interact with concrete. The CLARA facility, financed by EDF, IRSN, GDF-Suez and CEA, has been designed to understand the heat transfer phenomena involved in the Molten Concrete–Corium Interaction (MCCI). The facility is composed of a pool of simulant liquids, percolated by air and internally heated by direct electrical current. It is in contact with several heat exchangers in order to maintain walls at a constant temperature and to measure local heat losses. The experiments performed aimed at studying the influence on heat transfer of liquid viscosity (varying from 1 to 10,000mPa.s by dissolution of hydroxyethyl cellulose in the water), air injection superficial velocities (ranging from 0 to 10cm/s) on both horizontal and vertical walls, and pool length.After a literature review on the existing heat transfer experiments and correlations for two-phase (liquid–gas) flow, the CLARA experiments are described. Then, the results obtained are presented: influence of superficial gas velocity and liquid properties (especially viscosity) on heat transfer, evaluation of ratio between heat transfer on vertical and horizontal interface, influence of the pool dimensions. Finally, the analysis and interpretation of CLARA experiments are given: comparison to the literature data, development of correlations concerning the heat transfer along the vertical and horizontal plate, comparison to results obtained with real materials. The results show that the presence of bubbles enhances heat exchange while an increasing viscosity lowers the heat transfer. The MCCI isotropic trends are different from those observed with prototypical materials suggesting that phenomena occurring at the corium–concrete interface are more complex than the ones present in CLARA experiments.

Multilayer nitride coating performance optimized by an artificial neural network approach

One of the most important problems occurred in many industries is due to friction and wear process. Over the years, minimizing friction and controlling wear is one of the difficult tasks for the researchers. Both properties can be minimized by the application of adequate coating technology. Many coating deposition technologies have been employed to limit friction and wear but only few succeeded, those are directly affected by the nature of the material under investigation and process parameters. A suitable coating strategy varying from single layer to multilayer should be applied to the materials whose superficial properties such as low friction, improved wear resistance, and adhesion are the prime interest. Multilayer coatings possess high hardness, ductility and fracture strength compared to single layer coatings. The advantageous properties of these multilayers can be preciously tailored according to specific application. For this purpose Physical Vapour Deposition (PVD) coatings have been developed considerably due to increasing industrial demands. In the present research, friction and wear study of multilayer PVD-nitride coating deposited on tool steel by unbalanced reactive magnetron sputtering technique have been discussed. Later on an Artificial Neural Network approach was used to predict the tribological properties of multilayer nitride films. Bias voltage, total gas flow rate, lap, time, velocity and load were considered as controllable factors. The regression and performance curve analysis is used to assess the optimized outcome of deposited film properties such as friction and wear. The analyzed results shows that experimented and predicted values are in a good agreement.

Review of the phenomenon of fluidization and its numerical modelling techniques

The paper introduces the phenomenon of fluidization as a process. Fluidization occurs when a fluid (liquid or gas) is pushed upwards through a bed of granular material. This may make the granular material to behave like a liquid and, for example, keep a level meniscus on a tilted container, or make a lighter object float on top and a heavier object sink to the bottom. The behavior of the granular material, when fluidized, depends on the superficial gas velocity, particle size, particle density, and fluid properties resulting in various regimes of fluidization. These regimes are discussed in detail in the paper. This paper also discusses the application of fluidized beds from its early usage in the Winkler coal gasifier to more recent applications for manufacturing of carbon nano-tubes. In addition, Geldart grouping based on the range of particle sizes is discussed. The minimum fluidization condition is defined and it is demonstrated that it may be registered slightly different when particles are being fluidized or de-fluidized. The paper presents discussion on three numerical modelling techniques: the two fluid model, unresolved fluid-particle model and resolved fluid particle model. The two fluid model is often referred to Eulerian-Eulerian method of solution and assumes particles as well as fluid as continuum. The unresolved and resolved fluid-particle models are based on Eulerian-Lagrangian method of solution. The key difference between them is the whether to use a drag correlation or solve the boundary layer around the particles. The paper ends with the discussion on the applicability of these models.

Microstructure and transmission electron microscopy characterization of electroless Ni–B thin films deposited on MWCNTs

In this work we report on the Ni–B electroless coating of multiwall carbon nanotubes (MWCNTs). Characterization was carried out using scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, Raman spectroscopy and thermogravimetric analysis. Prior to Ni–B coating MWCNTs were cleaned, sensitized and activated. Then the electroless coating was achieved by immersion for 1, 3 and 5min. For immersion time of the 5min the obtained coatings were homogeneous along the MWCNTs and without voids; the structure is mainly crystalline with some amorphous regions. This coating process was developed to give MWCNTs thermal stability on air and to change its superficial properties for several applications, mainly to be homogeneously mixed with liquid metals to increase their mechanic properties.

Tribological Performance and Microstructural Analysis of an Aluminium Alloy Based Hybrid Composite Produced by P/M

In the field of material science and engineering, there is a great impact ever since the invention of composites materials. High strength to weight ratio provides the attractive combination that moves composite materials into new era. The conventional materials like cast iron, steel, and aluminium alloy are replaced by the composite materials due to its superficial properties and could be applied in aerospace and automotive applications. Powder metallurgy fabrication technique is one of the best and attractive methods for producing metal matrix composites because of its better distribution of particles and reliability and cost in manufacturing. In this paper, composites based on aluminium alloy (Al 2024) reinforced with 10% weight fraction of hard ceramics like Aluminium oxide (Al2O3) and 10% weight fraction of Aluminium oxide (Al2O3) with 5% graphite particles is produced by Powder metallurgy method. Hardness and wear test are conducted for the Al 2024, Al-10%Al2O3, and Al-10% Al2O3-5% Graphite. In addition the surfaces of the composite are analyzed by SEM to study the wear of the composites.

Mechanism of fracture related heating for 500-kV composite insulators in highly humid areas

SUMMARY With the adoption of composite insulators in the field of high voltage transmission, it is essential to focus on its safety performance. Our study paid attention to the extensive heating within HV ending of 500-kV AC composite insulators in southern China with high level of humidity and proposed corresponding countermeasures. Via superficial examination, IR and UV test, interface quality inspection, chemical analysis and water absorption test and etc., we were able to study the defected insulators. According to our observation, insulators were slightly covered with pollutants and maintained superficial hydrophobic properties. The heating performance of HV ending of insulators was closely related to humidity as well as the type and site of loading voltage. We suggested that when exposed to high humidity, polarization of the molecules from water, polar groups of material and the interlayer resulted in the abnormal heating; on the other hand, when the environment humidity was low the heating was attributed to partial discharge. Consequently, we provided several solutions toward the issue according to our observations. Copyright © 2015 John Wiley & Sons, Ltd.

Effect of the Shot Peening Process on the Corrosion and Oxidation Resistance of AISI430 Stainless Steel

Ferritic stainless steels are used in specific applications where corrosion resistance, oxidation resistance and a high mechanical resistance are required. Shot peening is a process applied to add residual compression stresses in metallic surfaces with the intent of improving the material when exposed to corrosion due to stress and fatigue. Some studies about the effect of the shot peening process on the fatigue resistance, bending fatigue behavior, and residual surface stress in the ferritic stainless steels have been performed. However, the effect of the shot peening process on the corrosion and oxidation resistance of the stainless steel is not well known. In this context, the purpose of this study is to evaluate the effect of the shot peening process on these superficial properties of ferritic AISI430 stainless steel. The obtained results showed that the ferritic AISI430 stainless steel samples treated with shot peening presented a significant modification on the surface morphology and an important decrease of oxidation and corrosion resistance, evidencing that the shot peening process compromises the chemical and physical properties of the surface.