Synthesis and characterisation of chromium carbides

Phase composition of Cr-C thin films deposited by a double magnetron sputtering system

“…The percentage of oxygen in the low-carbon sample is higher due to the gettering effect of Cr. However, the role of the oxygen in the investigated Cr-C films is not as big as in the cases where reactive sputter deposition was used, 16 because of the low substrate temperature in the deposition process and the use of Ar as sputtering gas.…”

Influence of the thermo-chemical conditions on the carbo-chromization process of α-Fe matrices obtained by powder sintering technique

“…Many studies reporting on the chromization of Fe-C matrices show that the formed carbides are mostly of Cr 23 C 6 , Cr 7 C 3 and Cr 3 C 2 type. Since the formation enthalpy of Cr 23 C 6 (Cr/C ratio of 3.83) is larger than that of Cr 7 C 3 (Cr/C ratio of 2.33), which is larger than that of Cr 3 C 2 (Cr/C ratio of 1.5) [12], the two carbides layers observed in our samples are either Cr 23 C 6 and Cr 7 C 3 , or Cr 7 C 3 and Cr 3 C 2 . These phases may contain some Fe, since a stepped profile with an increasing Fe concentration is observed in each layer while moving from the surface towards the sample core ( Fig.…”

“…No traces of Cr 23 C 6 phase could be detected in any of the samples. This let us think that although Cr 23 C 6 has the most negative enthalpy of formation with respect to the other chromium carbides [12], the Cr concentration with respect to C (i.e. the Cr/C ratio) in the coating layer never gets sufficiently high to form Cr 23 C 6 as the diffusion of Cr occurs too rapidly.…”

Interaction of Polyol Esters and Phosphate Esters with Metal Carbides

“…Below 930°K, Cr 2 O 3 is the only phase present. Between 970 and 1050°K, the Cr 23 C 6 phase is present and above 1070°K the Cr 7 C 3 phase is the only phase present [5]. In addition, chromium oxide at the surface is converted to chromium carbide under these conditions [6].…”