Effect Of Metal Addition Research Articles

Effects of Metallic Additives on the Shape of GMA Weld Deposit

Effects of Metallic Additives on the Shape of GMA Weld Deposit

Studies on reduced scale tribometer to investigate the effects of metal additives on friction coefficient – Temperature sensitivity in brake materials

▶ New approach defined in this study on RSP proved to have potential to study temperature sensitivity of μ (fade and recovery behavior). ▶ This method has significant advantages such as very limited infrastructure, substantially less testing time and manpower along with extremely low cost as compared to the standard method on full scale dynamometer. ▶ Use of metallic ingredients in NAO friction composites affected all performance properties in a beneficial way. Cu was most effective in boosting TC significantly followed by brass and iron). ▶ Inclusion of metallic fillers enhanced all performance parameters related to friction and wear. Copper which is most expensive filler proved best followed by brass (moderately expensive) while iron powder (cheapest) was least effective in boosting performance of reference composite. ▶ Increased TC of the composites due to metallic fillers was the main reasons for improved friction performance. Standard methods practiced by the industry to evaluate performance of friction materials need huge infrastructure, manpower and time. It is necessary for researchers working in this applied field to develop a different approach to screen the potential of friction materials on reduced scale prototype (RSP) which would rank the materials based on performance. In this paper a new test methodology is reported to study the influence of metallic contents on temperature sensitivity of friction composites on RSP. Three friction composites were developed with identical parent composition (90% by wt.) except metallic filler viz. brass, copper and iron powder (10% by wt.). One more was developed without metallic powder by adjusting 10% amount with barite (space filler). All composites were characterized for physical, chemical and mechanical properties. These were tribo-tested on RSP for friction, wear, fade and recovery behavior as per new test methodology. It was concluded that with use of metal contents, friction and wear performance of composites improved in general. Copper containing composite showed best friction and wear behavior followed brass, while iron powder based composite showed moderate behavior. Thus new test methodology proved very effective to rank the performance of friction composites.

Effect of metallic addition on mechanical properties in an aluminum–graphite composite synthesized by means of mechanical milling

The increase on mechanical properties of different graphite dispersions in aluminum-based composites was studied. Al composites with metal-coated graphite (MCG) were prepared by mechanical milling route. Selected MCG couples were C–Cu, C–Ni and C–Ag while uncoated graphite was used as reference. As-milled products were consolidated by uniaxial cold compression followed by pressure-less sintering, hardness and compression tests were carried out on a longitudinal direction. Experimental values showed a significant increment on yield strength and hardness values in synthesized composites with respect to the blank (pure milled Al) processed under same conditions. Metal type and its concentration have an important effect on mechanical properties of prepared composites.

3-6 廃棄物熱分解タール改質用鉄触媒に及ぼす金属の添加効果((2)ガス化2,Session 3 バイオマス等,研究発表(口頭発表))

3-6 廃棄物熱分解タール改質用鉄触媒に及ぼす金属の添加効果((2)ガス化2,Session 3 バイオマス等,研究発表(口頭発表))

31P NMR peak width in humate–phosphate complexes

The mobility of inorganic phosphate (P) attached to solid humic acid (HA) and fulvic acid (FA) via a metal “anchor” was investigated by 31P NMR spectroscopy. The peak width of the 31P resonance was monitored as an indicator of the degree of attachment of the element to the humic matrix. The concept was demonstrated by contrasting peak widths of thoroughly dry M–HA–P complexes with those that had been allowed to absorb different amounts of moisture. It was shown that the presence of moisture, which enhances the mobility of P, results in a significant reduction of chemical shift peak width. The work was extended to comparisons between dry systems with and without metal anchors; systems with anchors consisting of different metals; systems comprising different humates and fulvates; and systems with different size fractions of a humate. It was shown that both the type of humate/fulvate, and the metal anchor used lead to different degrees of mobility within the humic matrix. It was also found that the effect of metal addition on 31P peak width is greater with fulvates and smaller HA fractions than with the larger HA components.

Effect of Metal Additives (Co and Ni) on the Electrochemical Properties of Lithium/FeS<sub>2</sub> Batteries

Iron, sulfur and transition metal powders were used as the starting materials to prepare iron disulfide (FeS2) cathode material at room temperature by high energy mechanical alloying. Modified FeS2 were also prepared by incorporation of transition metals like Co and Ni. Li/FeS2 cells with the prepared iron disulfides as cathodes were studied for discharge properties at room temperature using the 0.5M LiTFSI in tetra(ethylene glycol) dimethyl ether (TEGDME). The first discharge capacities of Li/composite FeS2 cell with 5 wt.% Co and 3 wt.% Ni were 571 and 844 mAh/g, respectively, compared to 389 mAh/g for the cell without any additive. The enhanced properties resulted from the better electronic conductivity of the material containing the metallic additive. The initial capacity and cyclic performance were improved when nickel and cobalt were added to prepare the modified iron disulfide.

Properties of sodium-based ternary phosphate glasses produced from readily available phosphate salts

Three series of phosphate glasses were produced by melting together sodium phosphate salt (NaH2PO4) and the phosphate salts of either calcium (CaHPO4), magnesium (MgHPO4·3H2O) or iron (FePO4·2H2O) in a 5% gold/95% platinum crucible at 1200°C. The glass compositions were confirmed by EDX and XRD analysis. Glass transition temperature (Tg), density and durability in water were determined for all the compositions. Maximum metal oxide contents before devitrification were between 55% and 59% for CaO+Na2O and 59% and 62% for MgO+Na2O. The normalized equivalent for Fe2O3+Na2O was between 55% and 61%. Density values for the glasses lay between 2.49 and 2.75gcm−3. Tgs lay between 295°C and 470°C. Degradation rates in deionized water at 37°C lay between 0.03gcm−2h−1 for Na phosphate glasses and 9×10−6gcm−2h−1 for Ca phosphate glasses, 3×10−6gcm−2h−1 for Mg phosphate glasses and <3×10−6gcm−2h−1 for Fe phosphate glasses. The effect of metal addition on properties goes as Fe>Mg>Ca for degradation rates and Tg and Fe>Mg≈Ca for density. The change in properties with metal addition was seen to be linear for Fe and Ca additions but not with Mg addition. This is in agreement with the anomalous behavior of magnesium phosphate glasses.

Enhanced activity of Ba-doped Ir/SiO 2 catalyst for NO reduction with CO in the presence of O 2 and SO 2

The effect of metal additives on the catalytic performance of Ir/SiO 2 catalyst for the selective reduction of NO with CO in the presence of O 2 and SO 2 was investigated. Among the 19 additives tested here, the addition of barium was the most effective to enhance the activity of Ir/SiO 2 at low temperature and low SO 2 concentration. Catalyst characterization suggested that barium prevents catalyst deactivation as an oxidation-retardant for the active Ir metal supported on SiO 2.

Copper- and Silver-Containing Monolithic Silica-Supported Preparations for Selective Propene−Propane Adsorption from the Gas Phase

Cylindrically shaped macroscopic-in-size bodies of aluminum-doped silica possessing uniformly sized mesopores have been used as supports for copper- and silver-based formulations in the selective adsorption of propene against propane in the gas phase. The metal addition was achieved using AgNO3 or Cu(NO3)2 in aqueous solution by either postsynthesis incipient wetness impregnation or direct incorporation in the synthesis stage, the overall metal content in samples being 2, 5, 10, and 20 wt %. The effect of metal addition on the degree of Al insertion into the silica matrix was evaluated by 27Al magic-angle spinning NMR. The nature of surface metal species was studied by X-ray photoelectron spectroscopy and temperature-programmed reduction by H2. Individual adsorption of propene and propane was measured at room temperature, and the selectivity coefficient was calculated as a function of the pressure and molar fraction of propene in the binary gas mixture. Within the series of Cu-derivatized adsorbents, the ...

Growth and characterization of nanocomposite yttria-stabilized zirconia with Ag and Mo

The effect of metal additions on the structure and properties of nanocrystalline yttria-stabilized zirconia (YSZ) thin films deposited by a hybrid magnetron sputtering/pulsed laser deposition technique was studied. The materials are candidates for use as adaptive, “chameleon” nanocomposites for tribological applications subjected to thermal cycling up to high (700 °C) temperatures. The composition, structure and mechanical properties of the films were characterized with X-ray photoelectron spectroscopy, electron dispersive spectroscopy scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction and nanoindentation. Increasing the metal content of the films by increasing the magnetron power resulted in decreased zirconia grain sizes for films with silver and/or molybdenum additions. The reduced zirconia grain size was attributed to a decrease in the ion-to-atom ratio during deposition. Unlike the YSZ–Ag films that exhibited reduced hardness with increasing metal content, YSZ–Mo film hardness increased from 12 to 17.5 GPa at 15 and 24 at.% molybdenum, respectively. Adding molybdenum to the films resulted in cracks and holes in the film surface indicative of molybdenum oxidation during processing. Adding both silver and molybdenum eliminated the undesirable surface features found in the YSZ–Mo films.

Effect of metal additives on L10 ordering of chemically synthesized FePt nanoparticles

Abstract The effect of additive Au, Ag, Pd, Cr, and Cu on the chemical ordering, magnetic properties, and grain growth of chemically synthesized FePt nanoparticles has been investigated. The L1 0 phase has been obtained by solution annealing and direct synthesis. Easy axis alignment has been obtained using dispersed L1 0 FePt nanoparticles.

Zn-promoted Rh/SiO2 catalyst for the selective reduction of NO with H2 in the presence of O2 and SO2

The effect of metal additives on the catalytic performance of Rh/SiO2 for the selective reduction of NO with H2 in the presence of O2 and SO2 was investigated. The addition of Zn was effective to enhance the catalytic activity of Rh/SiO2 for NO reduction at low temperatures and high O2 concentrations. The structural characterizations of Zn/Rh/SiO2 samples and in situ FT-IR measurements revealed that Zn additive plays two important roles in enhancing the catalytic activity of Rh/SiO2: (i) prevention of catalyst deactivation as an oxidation–retardant for the active Rh metal species supported on SiO2 and (ii) promotion of a reaction step, which generates NHx species as a key reaction intermediate for NO reduction by H2 in the presence of O2 and SO2.

Metal toxicity affects fungal and bacterial activities in soil differently.

Although the toxic effect of heavy metals on soil microorganism activity is well known, little is known about the effects on different organism groups. The influence of heavy metal addition on total, bacterial, and fungal activities was therefore studied for up to 60 days in a laboratory experiment using forest soil contaminated with different concentrations of Zn or Cu. The effects of the metals differed between the different activity measurements. During the first week after metal addition, the total activity (respiration rate) decreased by 30% at the highest level of contamination and then remained stable during the 60 days of incubation. The bacterial activity (thymidine incorporation rate) decreased during the first days with the level of metal contamination, resulting in a 90% decrease at the highest level of contamination. Bacterial activity then slowly recovered to values similar to those of the control soil. The recovery was faster when soil pH, which had decreased due to metal addition, was restored to control values by liming. Fungal activity (acetate-in-ergosterol incorporation rate) initially increased with the level of metal contamination, being up to 3 and 7 times higher than that in the control samples during the first week at the highest levels of Zn and Cu addition, respectively. The positive effect of metal addition on fungal activity then decreased, but fungal activity was still higher in contaminated than in control soil after 35 days. This is the first direct evidence that fungal and bacterial activities in soil are differently affected by heavy metals. The different responses of bacteria and fungi to heavy metals were reflected in an increase in the relative fungal/bacterial ratio (estimated using phospholipid fatty acid analysis) with increased metal load.

The effects of metallic catalysts on light crude oil oxidation in limestone medium

In this study, 28 experiments were performed to study the effects of metallic additives on light crude oil oxidation in limestone medium. Karakuş and Beykan crude oils from Turkish oil fields were used. The metallic additives were ferric chloride (FeCl 3), copper chloride (CuCl) and magnesium chloride (MgCl 2·6H 2O). The mixture of aqueous solutions of three metallic salts with limestone and the crude oils was subjected to a controlled heating schedule under a constant flow rate of air. The produced gas was analysed for its oxygen and carbon oxides contents. The results of reaction kinetics showed that the molar CO 2/CO ratio values of fuel combustion increased when additives were added. A decrease in the atomic H/C ratio with an increase in temperature was observed for all runs. The reaction order, m in Arrhenius equation increases as concentration of copper and magnesium chloride additive increases but decreases as ferric chloride additive increases in both crude oils. It is observed that the metallic additives except ferric chloride decreased the Arrhenius constant, Ar, for both crude oils. As concentration of ferric chloride increases the activation energy of Karakuş crude oil increases while activation energy of Beykan crude oil decreases. The copper chloride additive shows same trend for both crude oils. The 1.0 mol% concentration decreases the activation energies. The 2.0 mol% magnesium chloride increases the activation energy of Karakuş crude oil while decreases the activation energy of Beykan crude oil more than 1.0 mol% does. For Karakuş crude oil, the oxygen consumption curves of 2.0 mol% of metallic additives show one peak. There is similar behavior between runs with 1.0 mol% of ferric chloride and magnesium chloride and runs with no additive, but the oxidation reaction peaks with metallic salts at both concentrations occurs at lower temperatures. For Beykan crude oil, all the additives lower the peak temperature when they are compared to standard run. The trends of the curves are actually the same. Copper chloride shows one peak with the 1.0 and 2.0 mol% runs for both crude oils.

Solid-Phase Synthesis and Sintering in Highly Disperse Oxide-Metal Powder Mixtures

The specifics of using ultrafine electroexplosive metal powders in powder metallurgy and ceramic technology are considered. The possibility of activating the processes of sintering and synthesis of certain complex oxides and silicates is demonstrated. The effect of metallic additives on hardness, strength, and other properties of materials is established. Reinforced powdered and solid composites are produced in the combustion of oxide-metal mixtures.

Microstructure of Portland cement pastes containing metal nitrate salts

In recent years, Backscattered Scanning Electron microscopy techniques (BSE), coupled with an image analysis system have been recognised as a powerful tool for quantitative analysis. This paper investigates the effect of metal additions (Ba, Cu, Ni, Zn, Cr (III), Pb and Cd) to Portland cement to produce a solidified product which meets the durability criteria quantified by the ratio of hydrated products and porosity. In addition, other indicators of the progress of cement hydration such as the bulk density and evaporable water of the solidified products were also measured. Metal concentrations of 0.1 and 1% per weight of cement at a constant water/cement ratio of 0.4 were examined. The same measurements were conducted on control samples of different water/cement ratio. The results have shown that the control samples at different W/C ratio showed consistent trend in residual cement porosity, density and evaporable water content. It also showed that low dosage of metal nitrate additions can reduce cement hydration by up to 50% and at the same time reduce the observable porosity. Overall, this work has shown that Scanning Electron Microscopy (SEM) and image analysis are powerful tools and could be used to quantify the observable porosity and cement hydration in solidified systems.

Glucose hydrogenation on Co–B amorphous alloy catalysts and the promoting effect of metal additives

AbstractTwo kinds of ultrafine Co–B amorphous alloy catalysts, denoted as P‐1 Co–B and P‐2W Co–B, were prepared by chemical reduction with borohydride in aqueous or 50% (v/v) ethanol/water solution, respectively. In comparison with the corresponding Co‐based crystalline catalysts and Ni‐based catalysts, these catalysts exhibited higher activity during the liquid phase glucose hydrogenation, possibly due to the unique amorphous characteristics and the lower d‐band electron density, which was favorable for hydrogen dissociative chemisorption. Addition of Cr‐, Mo‐ or W‐promoters could further increase the conversion of Co–B amorphous catalyst, which was mainly attributed to the dispersion effect of promoters and the adsorption and polarization of carbonyl groups by these promoters. The different effects of W‐ from Cr‐ and Mo‐promoters on the conversion were observed and are discussed.© 2001 Society of Chemical Industry

Post-irradiation examination of high burnup Mg doped UO 2 in comparison with undoped UO 2, Mg–Nb doped UO 2 and Ti doped UO 2

The pellets of UO 2, magnesium doped UO 2 (Mg–UO 2), magnesium and niobium doped UO 2 (Mg–Nb–UO 2) and titanium doped UO 2 (Ti–UO 2) were irradiated to burnups ranging from 19 to 94 GWd/tU at temperatures 550–930°C. The solubility of magnesium in UO 2 was low around 2 mol%. The addition of magnesium and titanium caused to form large grain sized pellet on sintering. The swelling of pellets during irradiation was unchanged by magnesium addition below 60 GWd/tU in agreement with the literature rate for UO 2. The thermal conductivity of unirradiated Mg–UO 2 was higher than that of undoped UO 2, which seemed to also hold for irradiated specimens. Pellet fracturing occurred by irradiation mainly by thermal stress. The undoped and metal doped UO 2 pellets in the 84–94 GWd/tU range at the irradiation temperatures of 560–640°C showed large bubbles and sub-divided grains of sub-micron size and the rim structure formation all over the surface. The xenon release from the pellets during irradiation increased with increasing burnup. In the fuels of close burnups, the xenon release increased rapidly with increasing temperature above about 600°C. At high burnups, the effect of metal addition seemed to recede unclear perhaps due to the formation of heavily damaged fuel matrix.

Effect of metal addition on the properties of As 2 Se 3 glass

Effect of metal addition on the properties of As 2 Se 3 glass

Catalytic Effects of Metallic Additives on The Combustion Properties of Crude Oils by Thermal Analysis Techniques

Differential scanning calorimetry (DSC) was applied to crude oil combustion in the presence and absence of metal chlorides. It was observed that in the presence of smaller ratios of metallic additives, the surface reactions were predominant and the catalyst did not affect the reactions much. Three reaction regions were identified as low temperature oxidation (LTO), middle temperature oxidation (MTO) and high temperature oxidation (HTO). Kinetic parameters of the reaction regions were determined with two different methods and the results are discussed.