Effect Of Fe Addition Research Articles

Crystallization of amorphous CoSiB alloys: Effect of Fe additions

The results of transmission electron microscopy and X-ray diffraction studies of the crystallization behavior of different CoSiB alloys with and without Fe additions are reported. It is shown that a metastable bcc phase is formed by crystallization in all of the alloys with Fe additions. The bcc phase is not observed in the alloys without Fe additions.

コークスガス化反応に対する鉄添加の影響

コークスガス化反応に対する鉄添加の影響

Effects of Catalysis and Composition of Inlet Gas on Gasification of Carbon and Coal

In order to develope a high speed-low temperature coal gasification process, the fundamental investigations on the effects of the metal (Fe, Co, Ni, Zn, Li) added over activated carbon and three kinds of coal chars and the component of gasifing gas mixture (H2O, H2O-H2 CO2 CO2-H2, H2, O2, O2-H2O; balanced with N2) on gasification rate and carbon selectivity converted to CO, CO2, and CH4 were carried out at 600° to 1000°C and atmospheric pressure by using thermobalance, gaschromatograph and X-ray diffractometer.The main results obtained were as follows:1) A trial approach with pure carbon (activated carbon prepared from PVDC-PVC copolymer resin by thermal decomposition in N2) modified with metal addition by impregnation method was confirmed to be useful to evaluate the catalytic gasification activity of metal compounds contained originally in coal and/or added intentionally as catalyst.2) Mixing H2 with gasifing gas of H2O or CO2 (mole ratio: H2/H2O or H2/CO2≥1) and addition of Fe (10%) to pure barbon or coal char promoted gasification rate and carbon selectivity to CO to produce a gas mixture which were rich in CO and H2. This was supported by the fact that gasification rate of coal chars contained iron compounds originally was much faster than that of coal char in which iron compound was not containd. Li added only 0.5% increased gasification rate greatly, but almost of carbon was converted to CO2 in any gasifing gases.3) The content of ca. 10% Fe added was the most preferable amount for gasification pure carbon with H2O-H2 mixture. In the case of the mole ratio of H2/H2O less than ca.l, regardless of the amount of Fe added, the poor-graphitziable hard carbon was formed to decrease gasification rate and to stop gasification on its midcourse in an extreme case. And in these cases, since, the added Fe was always datected to be Fe3O4, Fe3O4 was supposed to promote formation of hard carbon.4) Remarkable effects of Fe addition always accompanied the more reduced state of iron oxide, e.g., FeO or metallic Fe. Therefore, the basic mechaism of the catalytic gasification with metal M (Fe, CO, Ni) was composed, presumably, of the oxygen transfer cycle betwean the oxidation of M with H2O (or CO2) to from MO and H2 (or CO) and the reduction fo Mo with carbon to give back to M and CO; the rate promotion by mixing H2 with H2O (or Co2) was due to the cotribution of reduction of Mo with H2 towards that of Mo with carbon.5) Since iron is relatively cheap as catalyst and recoverable from gasified residue or ash, this iron catalyzed gasification process will be promising practically.

The effect of fe additions on the embrittlement of Cu-Bi alloys

The effect of iron additions on the embrittlement of Cu-Bi alloys was studied by monitoring the ductility and grain boundary chemistry of embrittled specimens as a function of iron content. Mechanical properties improved for the same embrittling heat treatment as the bulk iron level increased, and this was correlated with a decrease in bismuth segregation to the grain boundaries. No iron was detected segregated to the boundaries, and several possible mechanisms were proposed to explain the beneficial effect of the iron additions. It was also found that approximately 70 min at 530°C is required to attain equilibrium for segregation of bismuth to the grain boundaries, and a diffusion coefficient derived from this data was found to be reasonable for bulk diffusion of bismuth in copper.