Phase Evolution and Oxidation Resistance of YSZ/(Ni,Al) Composite Coatings in CH_4 Atmosphere

YSZ/（Ni, Al） composite coatings with different Ni：Al mole ratios were deposited on superalloy Inconel 600 by electrophoretic deposition（EPD） technique, followed by sintering in CH_4 atmosphere at 1 100 ℃for 2 h and isothermally oxidation at 1000 ℃ for 50 h. After sintering at 1100 ℃ for 2 h in CH_4 atmosphere, besides ZrC and t-ZrO_2 phases, the phase constitutes of Ni：Al mole ratios with 1：3, 1：2, and 1：1 were（Zr, Al）C, AlNi_3 and Ni phases, respectively. A remarkable difference in the oxidation behaviors of YSZ/（Ni, Al） composite coatings with different Ni：Al mole ratios was observed. For YSZ（Ni：Al=1：3） coated sample, oxidation at 1000 ℃ causes decomposition of the（Zr,Al）C solid solution to metallic Al, and then most of the Al is oxidized to Al_2O_3. For the YSZ（Ni：Al=1：2） coated sample, oxidation at 1000 ℃ mainly causes decomposition of the AlNi_3 phase. For YSZ（Ni：Al=1：1） coated sample, after oxidation at 1000 ℃, most of the Ni is oxidized to Ni O phase, and tolerated 50 h of oxidation and finally cracked and spalled from the specimen. YSZ（Ni：Al=1：3） and YSZ（Ni：Al=1：2） coated samples show superior oxidation resistance than that of YSZ coating. The different oxidation resistance mechanisms of YSZ/（Ni, Al） composite coatings sintered in CH_4 atmosphere were discussed.

The Friction and Wear Properties of the Spherical Plain Bearings with Self-lubricating Composite Liner in Oscillatory Movement

A test method based on the condition simulation and a friction and wear test machine featuring in oscillatory movement were set up for self-lubricating spherical plain bearings (SPB). In the machine the condition parameters such as load, angle and frequency of oscillation and number of test cycles can be properly controlled. The data relating to the tribological properties of the bearing, in terms of friction coefficient, linear wear amount, temperature near friction surface and applied load, can be monitored and recorded simultaneously during test process by a computerized measuring system of the machine. Efforts were made to improve the measurement technology of the friction coefficient in oscillating motion. In result, a well-designed bearing torque mechanism was developed, which could reveal the relation between the friction coefficient and the displacement of oscillating angle in any defined cycle while the curve of friction coefficient vs number of testing cycles was continuously plotted. The tribological properties and service life of four kinds of the bearings, i.e, the sampleⅠ-Ⅳ with different self-lubricating composite liners, including three kinds of polytetrafluoroethylene (PTFE) fiber weave/epoxy resin composite liners and a PTFE plastic/copper grid composite liner, were evaluated by testing, and the wear mechanisms of the liner materials were analyzed.

Preparation and properties of the Ni-Al/Fe-Al intermetallics composite coating produced by plasma cladding

A novel approach to produce an intermetallic composite coating was put forward.The microstructure,microhardness,and dry-sliding wear behavior of the composite coating were investigated using X-ray diffraction （XRD）,scanning electron microscopy （SEM）,energy dispersive spectrum （EDS） analysis,microhardness test,and ball-on-disc wear experiment.XRD results indicate that some new phases FeAl,Fe0.23Ni0.77Al,and Ni3Al exit in the composite coating with the Al2O3 addition.SEM results show that the coating is bonded with carbon steel metallurgically and exhibits typical rapid directional solidification structures.The Cr7C3 carbide and intermetallic compounds co-reinforced composite coating has a high average hardness and exhibits an excellent wear resistance under dry-sliding wear test compared with the Cr7C3 carbide-reinforced composite coating.The formation mechanism of the intermetallic compounds was also investigated.

Properties of Al/Conductive Coating/α-PbO2-CeO2-TiO2/β-PbO2-WC-ZrO2 Composite Anode for Zinc Electrowinning

The properties of Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-WC-ZrO2 composite anode for zinc electrowinning were investigated. The electrochemical performance was studied by Tafel polarization curves（Tafel）, electrochemical impedance spectroscopy（EIS） and corrosion rate obtained in an acidic zinc sulfate electrolyte solution. Scanning electron microscopy（SEM）, X-ray diffraction（XRD）, and energy dispersive X-ray spectroscopy（EDXS） were used to observe the microstructural features of coating. Anodes of Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2, Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-WC, Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-ZrO2, and Pb-1%Ag anodes were also researched. The results indicated that the Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-WC-ZrO2 showed the best catalytic activity and corrosion resistant performance; the intensity of diffraction peak exhibited the highest value as well as a new PbWO4 phase; the content of WC and ZrO2 in coating showed the highest value as well as the finest grain size.

Effect of graphite content on wear property of graphite/Al_2O_3/Mg-9Al-1Zn-0.8Ce composites

Using squeeze-infiltration technique, Mg-9Al-1Zn-0.8Ce composite reinforced by graphite particles and Al2O3 short fibers was fabricated. The reinforcing phases combined closely with the matrix and no agglomeration was observed. The microstructure, hardness and wear property of the composites with the graphite content of 5%, 10%, 15% and 20% were investigated, respectively. The results reveal that Ce tends to enrich around the boundaries of graphite particles and Al2O3 short fibers, and forms Al3Ce phase. When the graphite content increases to 20%, the grain size becomes small. Moreover, with increasing the graphite content, the microhardness of the composites decreases but the wear resistance increases. The graphite which works as lubricant during dry sliding process decreases the wear loss. At low load, the wear mechanism of the composite is mainly abrasive wear and oxidation wear; at high load, except that the composite with 20% graphite is still with abrasive wear and oxidation wear, the wear mechanism of other composites changes to delamination wear.

Effect of Attapulgite Added in Plating Bath on the Properties of Ni/TiC Nano-composite Coatings

Pure copper plates were coated by Ni-TiC dipulse current plating method. The effects of adding different concentration（ranging from 0.5 g/L to 3.0 g/L） of attapulgite nano particles to the plating bath on the surface morphology, wear resistance, and oxidation resistance of Ni/TiC/Attapulgite nano-composite coatings were investigated. The experimental results show that the composite coating is flat and compact with adding 3.0 g/L in the bath, and the coating preferred orientation is changed from the planes（111） to（200）. The coefficient of the composite coatings decreases from 0.68 to 0.18 with increasing content of attapulgite in the bath, a mixed mode of adhesive-abrasive wear occurs for all coatings, and the wear mechanism shows a transition from adhesive-abrasive to predominantly abrasive wear mechanism when the concentration of attapulgite is beyond 1.5 g/L in electrolyte. The oxidation resistance of composite coatings is the best prepared when adding attapulgite particles at 0.5 g/L in the bath, the oxide mainly consists of a NiO phase by X-ray analysis.

Influence of microstructure on the corrosion resistance of Fe–44Ni thin films

An Fe–44Ni nanocrystalline（NC） alloy thin film was prepared through electrodeposition. The relation between the microstructure and corrosion behavior of the NC film was investigated using electrochemical methods and chemical analysis approaches. The results show that the NC film is composed of a face-centered cubic phase（γ-（Fe,Ni）） and a body-centered cubic phase（α-（Fe,Ni）） when it is annealed at temperatures less than 400℃. The corrosion resistance increases with the increase in grain size, and the corresponding corrosion process is controlled by oxygen reduction. The NC films annealed at 500℃ and 600℃ do not exhibit the same pattern, although their grain sizes are considerably large. This result is attributed to the existence of an anodic phase, Fe0.947Ni0.054, in these films. Under this condition, the related corrosion process is synthetically controlled by anodic dissolution and depolarization.

Analysis of Shop cold water stability of asphalt concrete composite

He cold asphalt concrete is laid composite that combines the advantages of rigid cement concrete and asphalt concrete flexible pavement materials and new waterproof materials, and it is also known as semi-rigid concrete or semi-rigid waterproof concrete. Cold paved asphalt concrete composite retains the advantages of rigid and flexible waterproof material waterproof material which abandoned both of their inadequacies, is waterproof material with a wide range of space research and application prospects. This study immersion Marshall test and freeze-thaw split test two test methods for cold-laid asphalt concrete composite conducted a comprehensive analysis of the stability of the water; the highest draw AC1-6 AC-20 immersion Marshall stability and 20.59, respectively, by testing MPa and 19.96 Mpa, freeze-thaw splitting strength to reach the highest ratio of 91% and 93% respectively, the value specification can be met, and through the analysis of the test data to identify the content of the asphalt cement content and cold water laid asphalt compound affect the stability of the peak will occur, so that it can be combined with concrete interfacial adhesion studies to further the comprehensive and accurate assessment of water resistance of the material.

PHASE STRUCTURE FACTOR AND INTERFACE CONJUNCTION FACTOR OF CAST IRON AND ITS COMPOSITION DESIGN

Theempiricalelectrontheory of solidsand molecules( EET) and theimproved TFDtheory wereapplied tocalculatethe phasestructurefactorsand interfaceconjunction factorsofcom mon alloying elementsincastiron. Akind of Si- Mo- Cu ductileiron with rareearth Mg asnodularizer was designed accordingtothese valenceelectron structure parameters. Actual applicationtestsshow thatthelongevity of thisiron is 1.5 timesof thatof high manganesesteel. This accordance of theoretical results and actual effectsshows the composition design methodcan beused in othercastiron research.

Effect of intensive vs conventional insulin therapy on perioperative nutritional substrates metabolism in patients undergoing gastrectomy

AIM: To investigate the effect of intensive vs conventional insulin therapy on perioperative nutritional substrates metabolism in patients undergoing radical distal gastrectomy. METHODS: Within 24 h of intensive care unit management, patients with gastric cancer were enrolled after written informed consent and randomized to the intensive insulin therapy (IIT) group to keep glucose levels from 4.4 to 6.1 mmol/L or the conventional insulin therapy (CIT) group to keep levels less than 10 mmol/L. Resting energy expenditure (REE), respiratory quotient (RQ), resting energy expenditure per kilogram (REE/kg), and the lipid oxidation rate were monitored by the indirect calorimeter of calcium citrate malate nutrition metabolism investigation system. The changes in body composition were analyzed by multi-frequency bioimpedance analysis. Blood fasting glucose and insulin concentration were measured for assessment of Homeostasis model assessment of insulin resistance. RESULTS: Sixty patients were enrolled. Compared with preoperative baseline, postoperative REE increased by over 22.15% and 11.07%; REE/kg rose up to 27.22 ± 1.33 kcal/kg and 24.72 ± 1.43 kcal/kg; RQ decreased to 0.759 ± 0.034 and 0.791 ± 0.037; the lipid oxidation ratio was up to 78.25% ± 17.74% and 67.13% ± 12.76% supported by parenteral nutrition solutions from 37.56% ± 11.64% at the baseline; the level of Ln-HOMA-IR went up dramatically (P < 0.05, respectively) on postoperative days 1 and 3 in the IIT group. Meanwhile the concentration of total protein, albumin and triglyceride declined significantly on postoperative days 1 and 3 compared with pre-operative levels (P < 0.05, respectively). Compared with the CIT group, IIT reduced the REE/kg level (27.22 ± 1.33 kcal/kg vs 29.97 ± 1.47 kcal/kg, P = 0.008; 24.72 ± 1.43 kcal/kg vs 25.66 ± 1.63 kcal/kg, P = 0.013); and decreased the Ln-HOMA-IR score (P = 0.019, 0.028) on postoperative days 1 and 3; IIT decreased the level of CRP on postoperative days 1 and 3 (P = 0.017, 0.006); the total protein and albumin concentrations in the IIT group were greater than those in the CIT group (P = 0.023, 0.009). Postoperative values of internal cell fluid (ICF), fat mass, protein mass (PM), muscle mass, free fat mass and body weight decreased obviously on postoperative 7th day compared with the preoperative baseline in the CIT group (P < 0.05, respectively). IIT reduced markedly consumption of fat mass, PM and ICF compared with CIT (P = 0.009 to 0.026). CONCLUSION: There were some benefits of IIT in decreasing the perioperative insulin resistance state, reducing energy expenditure and consumption of proteins and lipids tissue in patients undergoing gastrectomy.

Composition Dependence and Irradation Effects on Residual Resistivity in Cu-Al Alloys

Residual electrical resistivity due to short-range order has been calculated for Cu100-xAlx (x=9.13,13.56, 14.5 and 14.76 in at pct) alloys using pseudopotential approach, and the results have been discussed in the light of experimental studies of the local-order structure of these alloys. In case of Cu85.5Al14.5, change in the total residual electrical resistivity due to neutron-irradiation effects has been estimated by including contributions from the short-range order and static atomic displacement correction. Our results show a decrease in the residual resistivity in the irradiated Cu-Al solid solution as compared to the unirradiated sample. This is in accordance with the experimental results

In Situ Synthesis of Heat Resistant Gradient Composite on Steel Surface

A heat resistant gradient composite was synthesized in situ on steel with the self-propagating high temperature synthesis （SHS） reaction of 3Ni-Al-Ti-C system during casting. The phases, microstructure, and composition of the composite were analyzed by using an X-ray diffractometer （XRD）, and a scanning electron microscope （SEM） coupled with an energy-dispersive X-ray spectroscope （EDS）. The formation mechanism of the composite is also discussed. TiC/Ni3 Al/steel gradient composite is achieved by forming the gradient distributions of Fe, Ni, and Al, accompanied with the gradient variation of the microstructure from TiC/Nia A1, to TiC/Ni3 Al/steel, and to steel. The composite is in situ synthesized through whole reaction of 3Ni-Al-Ti-C system in liquid steel and densification procedure, and the liquid steel infiltrates into pores in the SHS product and forces liquid Ni3Al to form self-compaction further.

Dispersion of multi-walled carbon nanotubes in poly(p-phenylene) thin films and their electrical characteristics

Dispersion of multi-walled carbon nanotubes in poly（p-phenylene） composite exposed to toluene was experimentally investigated. 3 mg of multi-walled carbon nanotubes with nominal size of 20 nm was compounded with 30 mg of poly（p-phenylene） with the presence of terpineol as binding initiator. To investigate an optimal condition for homogenizing all constituents, ultrasonication with an output power of 750W was employed with compounding time of 3, 10, 20 and 30 min. With FTIR analyses, it could be confirmed that homogeneous composite of multi-walled carbon nanotubes and poly（p-phenylene） could be prepared. SEM analyses were also conducted to examine the dispersion of multi-walled carbon nanotubes in the polymer matrix. Then intrinsic electrical resistance of the composites after being exposed to toluene was also investigated. It was found that the composite film prepared with ultrasonication for 20 min could provide sufficiently sensitive response with respect to varied concentration of toluene.