Authors: J L Rico J S J Hargreaves
Publish Date: 2017/01/19
Volume: 52, Issue: 9, Pages: 5188-5193
Abstract
With the aim to obtain iron tubular microstructures attractive for various applications we have used a natural biogenic iron ochre as a raw material and explore various procedures and experimental conditions to achieve our goal Our experiments included reduction nitridation and characterization of microtubes derived from biogenic iron ochre Various temperatures of reduction under streams of H2/N2 or NH3 were tested Our results show that the tubular structure is maintained after reduction of the natural material under H2/N2 In addition ammonia was not produced under our experimental conditions and as expected hydrogen reduced the material However the treatment under NH3 reduces the material and allows the incorporation of nitrogen into the structure of the solid yielding iron nitride microtubes Reduced and nitrided microstructures were successfully obtained from natural biogenic iron ochre A temperature of 500 °C seems to be suitable to expose the calcined biogenic iron ochre under H2/N2 for 4 h or under ammonia for 8 h to obtain reduced or nitrided microtubes respectively The stability of the tubular structure during reduction/reduction–nitridation is maintained under both treatments Further interesting applications of this natural biomaterial could be envisagedThe authors thank Mr Gangi Reddy Ubarra for CHN analysis and James and Christopher Hargreaves for collecting the iron ochre In addition JLR thanks CONACyT for the financial support received during his sabbatical period at the University of Glasgow Scotland UK
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