Oxidation or Nitridation Behavior of Pure Chromium and Chromium Alloys Containing 10 mass%Ni or Fe in Atmospheric Heating

On the Oxidation and Nitridation of Chromium at 1300 °C

“…9a), the nitridation of chromium does not occur in 1 atm nitrogen. Hence nitrogen penetration does not result from lattice diffusion through the Cr 2 O 3 layer as proposed by Taneichi et al [16], nor by diffusion along grains boundaries of the chromia layer which could be preferential paths for N 2 .…”

“…The cracks appear during cooling at room temperature and are affected by the geometry of the sample. Taneichi et al [16] reports thermal expansion coefficient values for Cr 2 O 3 , Cr and Cr 2 N of 7.3, 9.5 and 9.41 9 10 -6 , respectively. These values may eventually explain the lack of adherence between the oxide layer and the substrate but does not support the fact that numerous cracks are present in Cr 2 N nor that the adherence between the substrate and the oxide layer could be modified by the presence of Cr 2 N.…”

“…Taneichi et al [16] suggest that nitrogen diffuses from the outer surface through the oxide and leads to nitride formation at the interface. Therefore the oxidation rate of chromium alloys in air cannot be evaluated only by measurements of the mass gain as it is usually done.…”

High rate deposition of thick CrN and Cr2N coatings using modulated pulse power (MPP) magnetron sputtering

“…The thermal stress is mainly generated by the mismatch between the substrate and the coating during the cooling period after the deposition due to the difference in the CTE values between the substrate and coating material [36]. It has been reported that the CTE for the 440C stainless steel substrate is 10.2× 10 −6°C−1 [37],while the CTE values for the CrN and Cr 2 N coatings are 2.3 × 10 −6°C−1 and 9.5 × 10 −6°C−1 , respectively [38][39][40]. Since the deposition and pulsing parameters are the same for the CrN and Cr 2 N coating depositions, the compressive stress caused by ion peening can be assumed similar.…”

Quaternary chromium-based alloys strengthened by Heusler phase precipitation

“…Finally, alumina is more thermodynamically stable than chromia [28]. Another drawback of chromia is the precipitation of nitrides beneath the oxide scale [5,7,29], indicating, as suggested by Klopp [1] and confirmed by Zheng and Young [30], that a chromia scale is permeable to nitrogen. On the contrary, as demonstrated by Han et al [31] by studying the oxidation behaviour of Ni-Cr-Al alloys, alumina scales prevent nitrogen to reach the metal and ensure an effective protection.…”