Showing papers in "Materials protection in 2014"
Journal Article•
TL;DR: In this paper, the residual stress, microhardness,elastic modulus, and surface roughness of Ni coatings were measured with an X-ray diffractometer, a nano-indenter system for mechanic measurements, and a surface profilometer.
Abstract: Based on the Watts bath,nickel coatings were prepared on Q235 A steel substrate with direct current electrodeposition method.The residual stress,microhardness,elastic modulus,and surface roughness of as-prepared Ni coatings were measured with an X-ray diffractometer,a nano-indenter system for mechanic measurements,and a surface profilometer.The effects of current density,temperature,and pH value on the mechanical properties of the Ni coatings were investigated,and the technology for the electrodeposition of the Ni coatings was optimized with orthogonal tests.Results showed that the Ni coating electrodeposited under a current density of 3.0 A/dm~2,a temperature of 45℃ and a pH value of 3.5exhibited the best mechanical properties;its grain size was 34.8nm,and its microhardness,elastic modulus,and surface roughness were as much as 3.86 GPa,238 GPa,and 0.182 μm,respectively.
2 citations
Journal Article•
TL;DR: In this paper, a trace amount of Cr was introduced into HAI77-2 aluminum- brass (denoted as Al-Cu) to improve its corrosion resistance in seawater and industrial cooling water.
Abstract: Atrace amount Cr was introduced into HAI77-2 aluminum- brass(denoted as Al-Cu) so as to improve its corrosion resistance in seawater and industrial cooling water.The corrosion rate and electrochemical behavior of six kinds of Al- Cu samples with different Cr dosage in 3.5%NaCl solution and 3.5%NaCl +0.5mol/L NH_4Cl solution were determined.The morphology and elemental composition of the corroded surfaces of the Al-Cu samples were analyzed by scanning electron microscopy and energy dispersive spectrometry,and the effect of Cr on their corrosion behavior was investigated.It was found that,on the one hand,Cr tended to agglomerate on Al-Cu alloy surface thereby reducing the corrosion resistance;on the other hand,Cr was able to form a passivation film on the alloy surface thereby improving the corrosion resistance.Moreover,the Al-Cu alloy containing 0.65%Cr exhibited good corrosion resistance in 3.5%NaCl,but Cr was unable to improve the corrosion resistance of the Al-Cu alloy in 3.5%NaCl +0.5 mol/L NH_4Cl solution.
1 citations
Journal Article•
TL;DR: In this article, the corrosion behavior of AZ31 Mg alloy betore and after friction-stir processing in 3.5% NaCl solution was evaluated with an electrochemical tester, an optical microscope, a scanning electron microscope and an analytical balance.
Abstract: The corrosion behavior of AZ31 Mg alloy betore and after friction-stir processing in 3.5%NaCl solution was evaluated with an electrochemical tester,an optical microscope,a scanning electron microscope and an analytical balance.It was found that,in Cl~-containing solution,Mg alloy after friction-stir processing exhibited higher corrosion potential,smaller corrosion current density,and higher impedance than untreated Mg alloy,and the former exhibited smaller corrosion- induced weight loss rate as well.Moreover,both untreated Mg alloy and treated Mg alloy were dominated by pitting,and the treated one underwent slighter pitting and exhibited better corrosion resistance,due to the formation of fine equiaxed grains and second phase solid solution.
1 citations
Journal Article•
TL;DR: In this paper, the performance of fluorocarbon surfactants at different concentrations in HC1 solution was investigated by using weight-loss method,polarization curve measurement,electrochemical impedance spectra measurement and scanning electron microscopic observation.
Abstract: The inhibition performance of fluorocarbon surfactant FCI- 3 and hydrocarbon surfactant cetyl trimethyl ammonium bromide(CTAB) for Q235 carbon steel in HC1 solution was studied.The inhibition performance of the surfactants at different concentrations in HC1 solution was investigated by using weight- loss method,polarization curve measurement,electrochemical impedance spectra measurement and scanning electron microscopic observation.Results indicated that both FCI-3 and CTAB surfactants belonged to mixed-type inhibitors,and they both functioned to inhibit the corrosion of the carbon steel by way of "geometric covering effect".The inhibition efficiency increased with increasing concentration of the inhibitors,and CTAB mainly inhibited anodic reaction.Moreover,FCI-3 exhibited better inhibition performance than CTAB.
1 citations
Journal Article•
TL;DR: The structure characterization and luminescent properties of the fluorescent sodalite incorporated with albite have been investigated in this paper, where it was identified that the crystal began transition at the annealing temperature over 1,000 ℃, and transformed into an amorphous glassy state at 1,300℃.
Abstract: The structure characterization and luminescent properties of the fluorescent sodalite incorporated with albite have been investigated. The XRD results showed that the main mineral phases is sodalite,and minor mineral phases is albite. Through the XRD and TG,DTA,DSC analysis,it is identified that the crystal began transition at the annealing temperature over 1,000℃,and transformed into an amorphous glassy state at1,300℃. The total mass loss rate of the sample was 3. 2% after certain annealing treatment,among them the structural water have the largest loss rate(about 2. 5%). The photoluminescence spectra consist of red and orange-yellow emission bands with peaks at 735and 620 nm,respectively,under 256 and 380 nm excitation at room temperature. The red and orange-yellow luminescence due to the Fe3 +and S2-center,respectively. Their red luminescence intensities were regularly decreased as the temperature of heat treatment increased. However the orange-yellow band increased at first and then decreased,and the optimal annealing temperature was 900℃.
1 citations
Journal Article•
TL;DR: In this paper, the effect of Ti on the spangle size and microstructure of hot-dipped Al-Zn-Si coatings was investigated with a stereo microscope, a scanning electron microscope, and an energy dispersive spectrometer.
Abstract: Hot-dipped Al-Zn-Si coatings with and without Ti were fabricated at the production lines of a steel plant.The surface and cross-section microstructure of as-fabricated hotdipped Al-Zn-Si coatings were analyzed with a stereo microscope,a scanning electron microscope,and an energy dispersive spectrometer;and the effect of Ti on the spangle size and microstructure of the hot-dipped Al-Zn-Si coatings was investigated.Results indicated that the two kinds of hot-dipped Al-Zn-Si coatings had similar snowflake- like morphology,and the Ti-containing coating had a smaller spangle size than the one without Ti.Besides,hot-dipped Al-Zn-Si without Ti had a course microstructure,while the one with Ti had fine microstructure and contained uniformly distributed dendrites.In one word,Ti functioned to accelerate the refining of the grains of the coatings,increase the amount of nucleation sites,and significantly reduce the size of the spangle,but it had a minor effect on the corrosion resistance of the hot-dipped Al-Zn-Si coating.
1 citations
Journal Article•
TL;DR: In this paper, the corrosion behavior of 7075 Al alloy in alkaline NaCl solution containing different concentration of NaOH was investigated by electrochemical method, and the effects of NaH concentration and Cl-content as well as temperature on the corrosion behaviour were explored.
Abstract: The corrosion behavior of 7075 Al alloy in alkaline NaCl solution containing different concentration of NaOH was investigated by electrochemical method,and the effects of NaOH concentration and Cl-content as well as temperature on the corrosion behavior were explored. Results indicated that,at lower NaOH concentration( 0. 1 ~ 0. 5 mol /L),the growth of barrier layer( the adhered layer of corroded products) was dominant on Al alloy surface,and the growth rate of the barrier layer rose with increasing NaOH concentration. Besides,at higher NaOH concentration( 1. 0 ~ 5. 0 mol /L),the dissolution of the barrier layer was dominant on Al alloy surface,and the degree of destruction of the barrier layer caused by hydrogen evolution rose with NaOH concentration. In the meantime,the presence of Cl-accelerated the hydrogen-evolution-induced damage of the barrier coating to some extent,and such an accelerating function augmented with elevating NaOH concentration. Moreover,in the solution consisting of 0. 04 mol /L NaOH and 0. 01 mol /L NaCl,temperature mainly influenced the growth of the barrier coating,and the growth rate of the barrier coating rose with elevating temperature.In the solution consisting of 0. 40 mol /L NaOH and 0. 01 NaCl,however,temperature mainly influenced the dissolution of the barrier layer,and the degree of hydrogen-evolution-induced damage of the barrier layer augmented with elevating temperature.
1 citations
Journal Article•
TL;DR: An ANSYS finite element model was established, and simulation calculation of the cathodeprotected pipelines at a gas recovery plant was conducted as discussed by the authors, where the effects of the vertical space for pipeline laying, the vertical distance from the anode bed to the pipeline and the coating material resistivity on potential distribution of the pipelines under cathodic protection were investigated.
Abstract: An ANSYS finite element model was established,and simulation calculation of the cathodeprotected pipelines at a gas recovery plant was conducted. The effects of the vertical space for pipeline laying,the vertical distance from the anode bed to the pipeline and the coating material resistivity on potential distribution of the pipelines under cathodic protection were investigated. It was found that the simulation calculation results based on the model were in good agreement with the experimental ones. This meant that the established model could be well used to provide basis for the cathodic protection arrangement and optimal design of the pipeline networks at the gas recovery plant.
1 citations
Journal Article•
TL;DR: In this paper, the effects of various factors affecting corrosion of aluminum alloy in deep sea environment, including dissolved oxygen content,temperature,pH,CO2content,salinity,hydrostatic pressure,flow velocity as well as microbial environment are reviewed.
Abstract: The effects of various factors affecting corrosion of aluminum alloy in deep sea environment,including dissolved oxygen content,temperature,pH,CO2content,salinity,hydrostatic pressure,flow velocity as well as microbial environment are reviewed. The corrosion characteristics and rules of aluminum alloy are summarized,and several methods for preventing corrosion of aluminum alloy in deep sea environment are introduced. In the meantime,current exposure methods of aluminum alloy in the real sea and the laboratory simulated accelerated corrosion tests are briefed.Moreover,the development trend of the study on corrosion of aluminum alloy in deep sea environment is prospected.
1 citations