Rare earth nitride, iron

As has been alluded to above, the catalysts are extensively transformed when exposed to a mixture of CO and H2 at T > / 225°C. This transformation was first noted by Takeshita, Wallace, and Craig (14) in the use of these materials as synthetic ammonia catalysts. RCo. and RFca, intermetallics were converted into iron or cobalt rare earth nitride. This was established by conventional x-ray diffraction measurements. Coon (16) observed that the RNis compounds were transformed by the CO/H2 mixture into R2O3 and Ni, and a similar transformation also was observed by Elattar et al. (17) for ThNis, UNis, and ZrNis. SEM and EDAX results on ThNis show the formation of nickel nodules 0.5 /un in diameter situated on a Th02 substrate. 

Altounian, Z., Chan, X., Liao, L. X., Ryan, D. H. Strom-Olsen, J. O. (1993). Structure and magnetic properties of rare earth iron nitrides, carbides and carbonitrides. Journal of Applied Physics, 73, 6017-22. 

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