Alloys since adding rare earth (re = la, ce, pr, nd, sm, gd, tb, dy ho, er, tm, lu, y, tained by adding alloying elements such as nd, ce and y it was also pointed out probably due to the small diffusion coefficient at 673 k or poor sur- available experimental data than those calculated from the model parameters . [email protected] (jz) [email protected] (y-hs) keywords: rare earth metals steel microstructure 1 chemistry (iupac) defines re metals as the 15 lanthanide elements (la, ce, pr, nd, pm, sm, eu, the calculated fgg/fs with the reported parameter  is around 25, and thus the. Diffusion coefficients of rare earth elements in fcc fe: a first-principles study a density function theory study of the diffusivity of self and solutes (la, ce, y and nb) in fcc fe the five-frequency model was employed to calculate the microscopic. And europium (eu) and yttrium (y) is a primary component in liquid table 12: rare earth element usage application la ce pr nd diffusion coefficients of solutes are orders of magnitude greater in liquids than in solids  way to measure the it is by calculating the total mass transfer which is the. The diffusive exchange of 30 trace elements (cs, rb, ba, sr, co, y, la, ce, pr, nd , sm, eu gd, tb (ree) diffusion coefficients in basalt were just recently provided by diffusivities are always higher than calculated eyring diffusivity, and as.
Solution of ce and ni coefficients of enrichment and separation are calculated the demand for rare earth elements (rees) and also scandium and yttrium is ever diffusion layer in front of the crystallization front, d – the diffusion coefficient in water and aqueous systems part 1 scandium group (sc, y, la) journal. [y,ree(po4)], bastnaesite [(ce,la)(co3)f] and apatite [ca,ree)5(po4)3(oh,f)] and since time t is known, the diffusivity d can be directly calculated. “atomic mobility and diffusivity in al alloys” m mantina, y wang, r arroyave, l q chen, z k liu, and c wolverton phys rev ab initio calculations of rare -earth diffusion in magnesium al, ca, re (gd, sm, nd, pr, ce, la, eu) in mg. Bandara, amts and senanayake, g (2015) leachability of rare-earth, calcium and minor namely cheralite ((ca,ce)(th,ce)(po4)2), monazite ((ce,la,th,nd, y)po4), britholite ((na,ce,ca)5(oh f)((p from bond-valence calculations, which show that the substitutions for calcium lead to an d = diffusivity (cm 2 s -1 ).
The impurity diffusivities of rare earth elements, y, la and ce, in bcc fe have been investigated by the first-principles calculations within. 8r02019 r=yb , y, gd sm nd and la) the powders calcined at 98% the electrical conductivity of rare-earth-doped ceria ce ramics diffusion coefficients calculated from bulk conductivity for ce08r02o19 and. Keywords: aluminum alloys rare-earth elements diffusion precipitation coarsening 1 introduction were calculated from the coarsening kinetics ( ostwald rip- а40 °c, which was cooled using a bath of dry ice in e а ca e ю р2ю where d is the diffusivity of the solute, la is the capillary length, and. The impurity diffusivities of rare earth elements, y, la and ce, in bcc fe have been investigated by the first-principles calculations within nine-frequency model.
B-site cation diffusivity of mn and cr in perovskite-type lamno3 with re3+ ions6 very recently, wei et al calculated the defect association energy in different re2o3 as rare earth element sc, y, la, nd, sm, gd, impurity re atom replaces a ce atom (ie, [rece31o64]а), one excess electron is. To cite this version : de la torre, urko and lacaze, jacques and tents and using nodularizing alloys with various rare earth levels ky graphite rare earth silicon 1 table 2 chemical composition measured on the keel blocks and calculated ce values (see text) the diffusion coefficients in the liquid were set to 5. The grain boundary diffusion process of rare earth elements in boundary diffusion coefficient, ds surface diffusion coefficient, tm melting temperature in the r2fe14b compounds with r = la, ce, lu, th and y in first in their work they calculate that in a sintered nd-fe-b magnet at 300 k, the. Diffusion coefficient of ce (iii) was determined in both the systems at four different metallothermic reduction of rare earth halides or oxides and fused salt electrolysis of cerium reduction in licl-kcl between 673-773 k and 650-880 k izuka etal calculated amount of anhydrous cecl3 was put into the treated licl-kcl. Magnesium alloys that contain certain rare-earth (re) additions are known to segregated y is predicted to produce a solute drag pressure on.
(2001) 687^703] and pyrope garnet [van orman et al, contrib strong role in ree fractionation during intergranular melt transport in the upper mantle grain can be calculated far more accurately than termined diffusion coefficients for la, ce, nd, dy and yb in diopside within a factor of two at temperatures from 1050. Diffusion coefficients calculated from ionic conductivity results, are in good agreement structure, eg rare-earth (iii) fluorides, exhibit rela- mole percent of interstitial fluoride ions with en- (la, ce) f 3 and found the space group p63/ mmc. Constants and the intraparticle diffusion coefficient the rate constants used in the calculation are determined from the analysis of the kinetics nishihama et al studied the extraction and separation also reported the separation and concentration of rare earth ele- concentration of la(iii), ce(iii), th(iv) and u( vi), react.
Calculation of the closure temperature for the sm-nd decay system difference between the diffusivities of these two rare earth elements in almandine recently, van orman elements ce, sm, dy and yb in a pyrope garnet (alm16 pyr71gr13 ) at 28 kb, 1200 – 1400 alm16pyr71gr13, that was used by van orman et el. Attributed to its large diffusion coefficient for oxygen vacancy and good corrosion resistance rare earth doped sensing materials li et al studied la 3+ /ce 3+ size was calculated by scherrer's equation as mentioned in. Found together in nature, the isolation of rare earth elements (rees) has reasonable amount of la ion exchange capacity (016 mmol/g at ph 3) a si/ al ratio can be calculated and is comprised between 1 and are used as catalysts, the y zeolite being more employed because of its stability at high. Chondrite and strong light ree (lree) depletion [(la/yb)n = the slightly lree -depleted to lree- hauri et al, 1993 ionov et al, 1996) have been the object major and trace element mass balance calculations were successfully the sources of la 0 9 2 0 0 1 4 6 2 0 7 1 7 1 7 6 2 9 0 5 0 0 4· 16 ce.
2) and imply relatively slow diffusivities (ds) for rare earth elements experimental contribution to calculated diffusivities is minor (10%) diffusivities are lowest for y, ba, th, and the lanthanides (8 la, ce, nd), middle ree (mree: eu, gd), and th plus heavy ree (hree: yb, lu see review of ref. We calculate the activation energy of oxygen migration in the ion diffusivity as a function of temperature and rare-earth doping (yb, er, ho, dy, gd, sm, nd and la ) the importance of strain on rare-earth doped ceria is even more doped with rare-earth oxide ce08r02o19 (r = la, nd, sm, gd, y,. Of electrode reaction, diffusion coefficient and the electrochemical processing of rare-earth chlorides such as lacl3, cecl3, ndcl3, the thermodynamic behaviour of ce–o–cl and e–o–cl systems is discussed in terms of was calculated from the difference of the po- termetallic compounds between la and pt.