Surface Of Stainless Steel Substrate Research Articles

Exploring the optimal electropolymerization strategy for the preparation of solid-phase microextraction fibers using pyrrole-dopamine copolymers

In-situ electropolymerization of conductive polymers on the surface of stainless-steel substrates is a well-established but promising procedure for the preparation of solid-phase microextraction (SPME) tools. Herein, different electrochemical methods including constant potential (CP), constant potential pulse (CPP), and cyclic voltammetry (CV) were utilized to fabricate SPME fibers by in-situ electropolymerization of pyrrole-dopamine copolymers (PPY/PDA) on the surface of stainless-steel fibers. The coated fibers were characterized and applied for the direct-immersion SPME (DI-SPME) sampling of ultra-trace amounts of plant hormones including abscisic acid (ABA), gibberellic acid (GA3), and indole acetic acid (IAA) in fruit juices, followed by HPLC-UV determination. The results showed that CV electropolymerization is significantly more efficient than the two other methods. The coatings created by the CV method were satisfactorily uniform, adhesive, and durable and exhibited higher extraction performance compared to the CP and CPP procedures. The important experimental variables of the proposed DI-SPME-HPLC method were evaluated and optimized using response surface methodology with a Box-Behnken design. The developed method showed wide-range linearities, spanning from 0.05 to 20μg mL−1 for GA3, and 0.02 to 20μg mL−1 for ABA and IAA. The limits of detection were obtained 0.01μg mL−1 for GA3, and 0.005μg mL−1 for ABA and IAA. The fiber was successfully employed for the simultaneous DI-SPME-HPLC analysis of plant hormones in fruit juice samples.

Effects of Ultrasound on Distribution of Laser Melt Injected WC Reinforced Particles on Stainless Steel Substrate Surface

Effects of Ultrasound on Distribution of Laser Melt Injected WC Reinforced Particles on Stainless Steel Substrate Surface

Thermal insulation and anti-vibration properties evaluation of modified epoxy resin-based thermal protection coatings in arc-jet

Thermal protection system (TPS) is crucial for hypersonic flight vehicles to effectively protect them against the aerothermal effect imposed on them during flying with high Mach number. A novel hybrid ablation thermal protection coatings (FHMP-ATPCs) on the surface of stainless steel substrate were prepared by doping iron trioxide (Fe2O3) powder, hollow glass microspheres (HGM) and mica powder (MP) into hydroxyl-terminated silicone oligomer-bridged epoxy resins (PSG) copolymer. The thermal insulation and structural reliability of the FHMP-ATPCs were investigated by a novel aerothermal-vibration coupling test system. During the test, the heat flux of the surface of coatings ranged from 400 kW/m2 to 700 kW/m2. Meanwhile, the vibration load was a random vibration with frequency range of 20–2000 Hz and root mean square of total acceleration (Grms) of 10.8 g. The maximum surface and back-face temperature reached 714.9 °C and 141.3 °C, respectively. Compared with epoxy resin based coatings，the PSG-based coatings showed excellent structural reliability during the test. This study demonstrates the robust effect of strategy of modifying epoxy resin with organosilicon in improving thermal insulation performance yet maintaining the structural reliability of the ablation thermal protection coatings, providing a promising route to achieve high-performance coatings.

Spreading behavior of Sn droplets impacting Cu and stainless steel substrates

With the development of droplet 3D printing, thermal spraying, spray molding, and other technologies, the collision diffusion process of metal droplets and metal substrates has become a key aspect in controlling these processes. This study used Sn droplets as the research object. Using a pneumatic pulse jet device, molten Sn droplets were impinged on the surface of copper and stainless steel substrates. The impact process was recorded by high-speed photography. The diffusion diameter and solid-liquid contact angle were measured from these images, revealing the difference in the diffusion of Sn droplets on different surfaces. This explains the difference in the droplet diffusion ability from the perspective of driving energy. The entire impact process and final morphology were considerably similar when the substrate temperature was lower than the melting point of Sn. When the substrate temperature was higher than the melting point of Sn, the entire diffusion behavior of the tin droplet from contacting the substrate to the steady state was investigated in stages. From the driving energy analysis, it was observed that the Sn droplet is mainly driven by its internal kinetic energy in the initial stage of diffusion. When the diffusion diameter approached the maximum value, the kinetic energy of Sn droplets gradually dissipated; the surface energy and viscous force work gradually increased, and the diffusion changed from a linear diffusion state to a slow diffusion state. Simultaneously, the surface energy and viscous force of the droplet played a key role. The adhesion of Sn droplets to the surface of the stainless steel substrate was very small, and the interface did not react, which caused the Sn droplets to shrink significantly on the stainless steel surface during the retraction stage.

Study of the influence of diamond-like carbon film deposition technology on the change of its physical and mechanical characteristics

The paper presents the results of testing the technology of deposition of diamond-like carbon films on the surface of stainless steel substrates at different process parameters, a quantitative assessment of the sp3 bond content and the physical and mechanical characteristics of the coatings obtained, a conclusion about the influence of the deposition process technological parameters on these characteristics is formulated.

Suppression of molten salt corrosion by plasma sprayed Ni3Al coatings

Corrosion behaviour of stainless steel 347 was investigated in a molten nitrate salt (60 wt% NaNO3 + 40 wt% KNO3) immersion at 565 °C for up to 3000 h. A growth of stratified oxide layers consisting of NaFeO2, Fe2O3 and Fe3O4 was observed on the stainless steel surface with a constant gravimetric corrosion rate of ~ 0.4 µm/year. The feasibility of using Ni3Al coatings deposited by means of air plasma spray for suppression of corrosion was investigated. Ni3Al coatings were observed to undergo a fast oxidation with a corrosion rate of ~ 2.7 µm/year in the first 500 h, and subsequently stabilise between 500 and 3000 h with no observable changes in microstructure, composition and weight at a corrosion rate of ~ 0.02 µm/year. The results presented in this study strongly suggest that Ni3Al coating suppresses the formation of oxide layers on the surface of stainless steel substrates and can be used as protection against corrosion in the presence of molten nitrate salts, which is of relevance to thermal energy storage applications.

Mechanically Alloyed CoCrFeNiMo0.85 High-Entropy Alloy for Corrosion Resistance Coatings.

High-entropy alloys could provide a solution for corrosion resistance due to their impressive properties. Solid-state processing of high purity Co, Cr, Fe, Ni and Mo metallic powders and consolidation resulted in a bulk material that was further machined into electro spark deposition electrodes. After the stainless steel substrate surface preparation, thin successive layers of the high-entropy alloy were deposited and Pull-Off testing was performed on the newly obtained coating, for a better understanding of the adhesion efficiency of this technique. Good adhesion of the coating to the substrate was proved by the test and no cracks or exfoliations were present. Corrosion resistance testing was performed in a liquid solution of 3.5 wt.% NaCl for 6 h at room temperature and the results obtained validated our hypothesis that CoCrFeNiMo0.85 high-entropy alloys could provide corrosion resistance when coating a stainless steel substrate.

Fabrication of a High-Performance Hybrid Supercapacitor Based on Hydrothermally Synthesized Highly Stable Cobalt Manganese Phosphate Thin Films.

In the present study, cobalt manganese phosphate (H-CMP-series) thin films with different compositions of Co/Mn are prepared on stainless steel (SS) substrate via a facile hydrothermal method and employed as binder-free cathode electrodes in a hybrid supercapacitor. The XRD study reveals a monoclinic crystal structure, and the FE-SEM analysis confirmed that H-CMP-series samples displayed a nano/microarchitecture (microflowers to nanoflakes) on the surface of SS substrate with excess available surfaces and unique sizes. Interestingly, the synergy between cobalt and manganese species in the cobalt manganese phosphate thin film electrode demonstrates a maximum specific capacitance of 571 F g-1 at a 2.2 A g-1 current density in 1 M KOH. Besides, the nano/microstructured cobalt manganese phosphate was able to maintain capacitance retention of 88% over 8000 charge-discharge cycles. More importantly, the aqueous/all-solid-state asymmetric supercapacitor manufactured with the cobalt manganese phosphate thin film as the cathode and reduced graphene oxide (rGO) as the anode displays a high operating potential window of 1.6 V. The aqueous asymmetric device exhibited a maximum specific capacitance of 128 F g-1 at a current density of 1 A g-1 with an energy density of 45.7 Wh kg-1 and a power density of 1.65 kW kg-1. In addition, the all-solid-state asymmetric supercapacitor device provides a high specific capacitance of 37 F g-1 at 1 A g-1 with 13.3 Wh kg-1 energy density and 1.64 kW kg-1 power density in a polymer gel (PVA-KOH) electrolyte. The long cyclic life of both devices (87 and 84%, respectively, after 6000 cycles) and practical demonstration of the solid-state device (lighting of a LED lamp) suggest another alternative choice for cathode materials to develop stable energy storage devices with high energy density. Furthermore, the aforementioned study paves the way to investigate phosphate-based materials as a new class of materials for supercapacitor applicability.

Biodiesel flames as a unique pyrolyzing carbon source for the synthesis of hydrophobic carbon films

We report the rapid single-step flame synthesis of hydrophobic carbon layers (C-layers) on the surface of stainless-steel (SS) substrates using vaporized biodiesel as the fuel. A co-flow canola methyl ester/air diffusion flame is used to generate a hydrophobic monolayer on the surface of the metal substrate upon its insertion into the reaction zone. Carbon deposition on the surface of the SS substrates varies by changing the SS disk’s position in the post-flame, and by varying its exposure time. The thickness and mass of the flame-formed monolayer varied depending on the substrate’s insertion point into the flame. However, the variation of mass did not significantly impact the C-layer’s uniformity or hydrophobicity. We hypothesize that a small “inner-cone” of the biodiesel flame along with a high soot propensity can result in an ideal medium to form uniform hydrophobic C-layers of unique hierarchical surface structure. This is supported by introducing SS substrates in methane/air flames formed using the same co-flow burner. The hydrophobic property of the carbon deposits was quantified by measuring the contact angle of water droplets placed on the film’s surface. A water droplet drop test was conducted on the flame-formed hydrophobic layers to study their wettability property.

Nanosecond laser fabrication of superhydrophobic surface on 316L stainless steel and corrosion protection application

Herein, we developed an facile, cost-effective and efficient method to fabricate microstructures of different scales on 316 L stainless steel substrate surface by laser modification. By changing the laser parameters, such as various laser fluence (2.69, 3.96, 6.28, 8.14,9.55 J/cm2) during laser irradiation, different sizes of micro-cracks and brain-like microstructures can be obtained. The experimental results indicate that a static contact angle of 160 ± 5° and the sliding angle of 3 ± 0.5°, can be achieved at a scanning interval of 30.0 μm and laser fluence of 8.14 J/cm2, which has the best outstanding wettability. In addition, the microstructures and chemical compositions on the surface were examined by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The corresponding corrosion resistance properties was evaluated by the means of potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The laser textured superhydrophobic surface was found to enhance the corrosion resistance dramatically. Also, after the laser modification, excellent self-cleaning performance was demonstrated based on tests with quartz sand particles. Particularly, we extensively discussed how the structures on the 316 L stainless steel were formed after the ultraviolet nanosecond laser irradiation and the interaction mechanism of the laser and substrate. This study not only provides important insights into the formation mechanism of laser textured surfaces, but also guides practical industrial applications as this approach is simple, low-cost and convenient for fabrication of large-area superhydrophobic surfaces on various metal materials.

Corrosion of stainless steel coated with a ZrO2 film in a hydrogen sulfide gas environment

A zirconia sol was prepared by the sol–gel method and coated on the surface of stainless steel substrates. The gas corrosion test was carried out for the stainless steel substrates and for the coated samples using a high-temperature and high-pressure reactor. The coated samples and the substrates were placed in the reaction kettle, and it was filled with the H2S gas at the pressures of 0.6, 0.8, and 1 MPa. After standing at room temperature for 24 h, the samples were observed by optical microscopy and a scanning electron microscopy, and it was found that as the pressure increases, the corrosion of the stainless steel substrates are more severe, while the film samples show only slight pitting corrosion. The experimental results show that in the corrosive H2S gas environment, the stainless steel samples coated with the ZrO2 film can effectively block the H2S gas corrosion on the stainless steel substrate and reduce the hydrogen bubbling and hydrogen-induced cracking caused by gas corrosion. This finding has important practical significance for improving the service life of oil pipelines and reducing the occurrence of oil spills and other accidents.

Influence of Ceramic Coating on Mechanical Properties of Stainless Steel

Crystal structure and phase composition of stainless steel substrates (AISI 304 type) was studied and it was found that they adopted the cubic symmetry. The calculated elementary cell parameter for the mayor Fe-Ni phase (weight fraction 99%) was a = 3.593 A, whereas the mean grain size was = 2932 A. Morphology of the stainless steel substrate surface was studied with profilometry. Mechanical properties of the stainless steel substrates and stainless steel substrates coated with ceramic layer of barium strontium titanate were studied with microhardness tester. For measurements performed according to the Vickers method the average microhardness was found HV = 189 or HV = 186 for the “in-line” and “mapping” measurement pattern, respectively. The sol-gel method was used to coat the surface of the stainless steel substrate with a thin ceramic layer of the chemical composition Ba0.6Sr0.4TiO3. It was found that the stainless steel substrate covered with sol-gel deposited ceramic coating exhibited the average hardness within the range HV = 217 up to HV = 235 for loading force F = 98 mN and F = 0.98 N, respectively. The Knopp method was also used and it was found that the stainless steel substrate with Ba0.6Sr0.4TiO3 coating exhibited hardness HK = 386.

Plasma Printing of Micronozzles With Complex Shaped Outlets Into Stainless Steel Sheets

Abstract The plasma printing was developed as a means to fabricate the micronozzle chip with the inner diameter less than 50 μm. The initial two-dimensional micropattern was printed onto the stainless steel substrate surface by the maskless lithography. These printed micropatterns were utilized as a mask to make selective nitriding into the unprinted surface. After removal of printed pattern, the un-nitrided surfaces were chemically etched to leave the nitrided microtexture as a micronozzle chip. High nitrogen supersaturation as well as selective nitrogen diffusion had influence on the spatial resolution in this plasma printing in addition to the digitizing error in the maskless lithography.

Structural color printing with a dielectric layer coated on a nanotextured metal substrate: simulation and experiment.

The printing of plasmonic structural colors relies on noble metal nanostructures fabricated on Si, glass, or plastic substrates. This paper presents a simple surface structure for producing vivid structural colors directly from common metal substrates. The structure is formed by texturing the surface of stainless steel (STS) via imprinting and coating it with a dielectric layer. Diverse colors are generated simply by varying the thickness of the dielectric layer. The colors arise from surface plasmon resonance and guided-mode resonance of the incident light, which are excited on the textured STS surface and inside the dielectric layer, respectively. A finite-difference time-domain simulation shows that 500 nm is the optimum texture periodicity with regard to the tunability and vividness of the colors. This is experimentally verified by printing many differently colored images on the surface of STS substrates with a texture period of 500 nm. The proposed structure/method does not require a nanofabrication technique such as electron-beam lithography or focused ion beam etching. The results of the study provide a facile route for producing vivid structural colors on metals, which may find various applications, including surface decoration, product identification, anti-counterfeiting, and perfect absorbers.

Efficiency enhancement of CIGS compound solar cell fabricated using homomorphic thin Cr2O3 diffusion barrier formed on stainless steel substrate

It is known that the efficiency of flexible Cu(In,Ga)Se2 (CIGS) solar cells fabricated on stainless-steel (STS) substrates deteriorates due to iron (Fe) and Cr impurities diffusing into the CIGS absorber layer. To overcome this problem, a nanoscale homomorphic chromium oxide layer was formed as a diffusion barrier by thermal oxidation on the surface of STS substrates for 1min at 600°C in oxygen atmosphere. By TEM and grazing-incidence X-ray diffraction (GIXRD), it was confirmed that the formed oxide layer on surface of STS substrates was a Cr2O3 layer. It was found that the formed homomorphic Cr2O3 thin layer of about 15nm thickness was an effective diffusion barrier to reduce impurity diffusion into the CIGS layer by secondary ion mass spectroscopy (SIMS). In contrast to the efficiency of CIGS solar cell without homomorphic Cr2O3 diffusion layer is 8.6%, whereas with diffusion barrier it increases to 10.6% because of impurities such as Fe and Cr from the STS substrate into the CIGS layer. It reveals that the layer formed on the surface of STS substrate by thermal oxidation process plays an important role in increasing the performance of CIGS solar cells.

Effect of temperature and concentration of precursors on morphology and photocatalytic activity of zinc oxide thin films prepared by hydrothermal route

Zinc oxide (ZnO) is an important semiconductive material due to its potential applications, such as conductive gas sensors, transparent conductive electrodes, solar cells, and photocatalysts. Photocatalytic activity can be exploited in the decomposition of hazardous pollutants from environment. In this study, we produced zinc oxide thin films on stainless steel plates by hydrothermal method varying the precursor concentration (from 0.029 M to 0.16 M) and the synthesis temperature (from 70 °C to 90 °C). Morphology of the synthesized films was examined using field-emission scanning electron microscopy (FESEM) and photocatalytic activity of the films was characterized using methylene blue decomposition tests. It was found that the morphology of the nanostructures was strongly affected by the precursor concentration and the temperature of the synthesis. At lower concentrations zinc oxide grew as thin needlelike nanorods of uniform length and shape and aligned perpendicular to the stainless steel substrate surface. At higher concentrations the shape of the rods transformed towards hexagon shaped units and further on towards flaky platelets. Temperature changes caused variations in the coating thickness and the orientation of the crystal units. It was also observed, that the photocatalytic activity of the prepared films was clearly dependent on the morphology of the surfaces.

Hierarchical 3D NiCo2O4 nanoflowers as electrode materials for high performance supercapacitors

Three-dimensional NiCo2O4 nanoflowers have been directly grown on a stainless steel substrate surface, using a facile chemical bath deposition (CBD) technique. The deposited thin films were characterized for their structural, morphological and electrochemical properties by using XRD, SEM, cyclic voltammetry and charge discharge methods. The 3D NiCo2O4 nanoflowers were used as working electrode to measure the supercapacitor performance. The 3D NiCo2O4 nanoflowers exhibit high specific capacitance of 543 Fg−1 at current density 1 Ag−1. The capacitance loss was 9.4 % after 1000 cycles at a current density of 3 Ag−1. This shows a good cycle stability and high rate capability of 3D NiCo2O4 nanoflowers. From this investigation it can be concluded that the low cost and environmental friendly CBD technique could be used to deposit efficient 3D NiCo2O4 nanoflowers for supercapacitor application.

Tribochemical synthesis of nano-lubricant films from adsorbed molecules at sliding solid interface: Tribo-polymers from α-pinene, pinane, and n-decane

The mechanochemical reactions of adsorbed molecules at sliding interfaces were studied for α-pinene (C10H16), pinane (C10H18), and n-decane (C10H22) on a stainless steel substrate surface. During vapor phase lubrication, molecules adsorbed at the sliding interface could be activated by mechanical shear. Under the equilibrium adsorption condition of these molecules, the friction coefficient of sliding steel surfaces was about 0.2 and a polymeric film was tribochemically produced. The synthesis yield of α-pinene tribo-polymers was about twice as much as pinane tribo-polymers. In contrast to these strained bicyclic hydrocarbons, n-decane showed much weaker activity for tribo-polymerization at the same mechanical shear condition. These results suggested that the mechanical shear at tribological interfaces could induce the opening of the strained ring structure of α-pinene and pinane, which leads to polymerization of adsorbed molecules at the sliding track. On a stainless steel surface, such polymerization reactions of adsorbed molecules do not occur under typical surface reaction conditions. The mechanical properties and boundary lubrication efficiency of the produced tribo-polymer films are discussed.

Effects of rapid thermal annealing for E-beam evaporated Ag films on stainless steel substrates

There is significant interest in the development of flexible substrates for making electronic devices such as solar cells and organic light emitting diodes using roll-to-roll processes. Stainless steel (STS) is commonly used for flexible substrates. To explore the potential for new STS applications (e.g., optical scattering layers in opto-electronic devices) silver thin films of ~100nm thickness were deposited on STS substrates using the thermal evaporation technique. The films then underwent rapid thermal annealing (RTA) to create various sizes of silver particles. The RTA method was carried out at annealed temperatures from room temperature (RT) to 550°C for 20min. We investigated variation of the surface morphology caused by the interaction between Ag films and STS substrates after the RTA annealing. The grain size was studied by using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) methods. When the film was annealed at 250°C, particles started to separate and the gaps between particles enlarged. However, at the high temperatures (450 and 550°C), we observed that the gaps decreased when the annealing temperature was increased from 350 to 550°C. In particular, the surface of STS substrate was completely covered with Ag particles for the film annealed at 550°C. The results showed the suppression of the agglomeration of the Ag film. Secondary ion mass spectroscopy (SIMS) and X-ray photoelectron spectroscopy (XPS) was used to examine the movement of Fe and Cr atoms in silver film from STS substrates. These atoms observed with SIMS and XPS must be at the surface. It was found that Fe and Cr atoms play a critical role in suppressing Ag agglomeration.The optical properties of annealed Ag films were studied by spectrophotometer. Broader absorbance was found for films with 450°C annealing temperature. The total reflectance of the Ag films annealed at 550°C increased over the wavelength range of 400–800nm, compared with that at 450°C. This was due to suppression of Ag agglomeration.

Electrochemical Characterization of Cathodized Copper Oxide Thin Films

Cathodic electrodeposited copper oxide thin films were prepared using 0.1 M aqueous (distilled water) copper sulfate solution onto the surface of stainless steel substrates. Deposited samples were characterized by structural and morphological analysis using XRD and SeM. Prepared samples were also analyzed using cyclic voltammetry, charge-discharge, and impedance spectroscopy. electrode shows nearly rectangular capacitive behavior. The highest specific capacitance of 62 F/gm was calculated at a scan rate of 1 mV/sec in 1M Na2SO4 electrolyte. The internal resistance observed from the Nyquist plot which is about 1.95 Ω. Using the ZsimpWin software matched equivalent circuit and circuitry parameters were reported.