The Preparation and Some Properties of Nd2O2C2

Butherus, A. Duane; Leonard, Ralph B.; Buchel, Gerald L.; Eick, H.A.

doi:10.1021/ic50043a022

Cited by 14 publications

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“…reaction 3, which was also proposed by Butherus et al 26 The fact that the reaction mixture had fused during thermal decomposition could indicate existence of a eutectic mixture of Nd 2 O 3 and NdC 2 . The possibility of a eutectic based upon observations of fused samples upon extraction is also mentioned by Butherus et al 26 In that work it was concluded that the eutectic was a result of reaction between Nd 2 O 2 C 2 and the graphite crucible. 26 In this work, tungsten crucibles were utilized, hence limiting available carbon.…”

supporting

confidence: 54%

“…The melting phenomena is also described by Butherus et al, who claimed that the Nd 2 O 2 C 2 compound started to melt partially at 1592 °C and completely at 1602 °C, agreeing well with the experimental observations of this work. 26 Thus, to ensure molten conditions in shorter time, the temperature was increased. Based on the results of this experiment as presented in Figure 6 and Figure 7, it was inferred that thermal decomposition of the Nd 2 O 2 C 2 phase was occurring at this temperature.…”

Section: ■ Discussionmentioning

confidence: 99%

“…The possibility of a eutectic based upon observations of fused samples upon extraction is also mentioned by Butherus et al 26 In that work it was concluded that the eutectic was a result of reaction between Nd 2 O 2 C 2 and the graphite crucible. 26 In this work, tungsten crucibles were utilized, hence limiting available carbon. Since the samples were still observed to be fused by use of tungsten crucibles it would be prudent to assume that any eutectic formed would thus be a consequence of the mixture of Nd 2 O 3 and NdC Cu−Nd Intermetallic Formation Mechanism.…”

mentioning

confidence: 85%

“…22−25 Carbothermic reduction of Nd 2 O 3 in absence of a metal solvent will form either the oxide carbide (Nd 2 O 2 C 2 ) or the dicarbide (NdC 2 ) depending on the available quantity of carbon, partial pressure of carbon monoxide (CO(g)) and the temperature. 26,27…”

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confidence: 99%

“…26,27 Information on the Nd−O−C system is unfortunately scarce, and only one paper by Butherus et al was found on the synthesis and properties of Nd 2 O 2 C 2 . 26 The current work thus, initially, addresses carbothermic reduction of Nd 2 O 3 in the presence of graphite, to evaluate thermal behavior of the Nd 2 O 2 C 2 phase. Subsequently, reactants featuring final Nd 2 O 2 C 2 stoichiometry were reduced by utilizing copper as a solvent metal and then analyzed to determine final product composition.…”

Section: ■ Introductionmentioning

confidence: 99%

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Formation of Copper–Neodymium Intermetallic Compounds by Carbothermic Reduction of Neodymium Oxide in the Presence of Copper

Ødegård

Tranell

2018

Ind. Eng. Chem. Res.

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Carbothermic reduction of neodymium(III) oxide (Nd 2 O 3 ) was performed by arc melting and in a graphite resistance furnace, using copper as a solvent metal. Successful carbothermic reduction was evident by formation of copper−neodymium intermetallics, where predominant phases were found to be Cu 6 Nd and Cu 5 Nd. The reduction reaction is proposed to be caused by thermal decomposition of neodymium oxide carbide (Nd 2 O 2 C 2 ) forming a molten mixture of neodymium(III) oxide and neodymium dicarbide (NdC 2 ) upon release of carbon monoxide (CO(g)), where subsequent decomposition of neodymium dicarbide was facilitated by a reduction in activity of formed elemental neodymium species solvated in molten copper. Addition of carbon in excess of neodymium oxide carbide stoichiometry was found to correlate with increased concentration of neodymium in copper, likely caused by an increase in concentration of neodymium dicarbide. 51 energy efficient, high productivity methods of producing and 52 recycling Nd are sought. 53 Due to the high affinity between rare earth elements and 54 carbon, forming a range of stable carbides and oxide carbides, 55 carbothermic reduction as a method of producing the 56 corresponding elemental compounds has been considered to 57 be difficult at best. 9 From available literature, several accounts 58 of carbothermic reduction with respect to elements that are 59 known to form stable carbides were found, among these, the 60 rare earths are represented. Some methods mentioned are 61 reduction by dissolving into suitable solvent metals, reaction 62 between carbides, and an element forming a more stable 63 carbide, formation of nitrides then vacuum decomposition of 64 said nitrides in solution with suitable solvent metals, etc. 10−18 65 Examples from literature reveals, among others, a patent by 66 Staggers that describes carbothermic reduction of rare earth 67 elements by formation of rare earth silicide alloys. 18 The 68 method apparently allows for the simultaneous carbothermic 69 reduction of rare earth oxides, especially cerium oxide (CeO 2 ) 70 along with alkaline earth oxides such as barium oxide (BaO), 71 calcium oxide (CaO), and strontium oxide (SrO) in the 72 presence of silica (SiO 2 ) and elemental iron (Fe) at elevated 73 temperatures, forming both rare earth and alkaline earth

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confidence: 54%

Section: ■ Discussionmentioning

confidence: 99%

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confidence: 85%

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confidence: 99%