Corrosion behaviour of Ni-based alloy Inconel 740H in supercritical carbon dioxide at 650–700°C

Abstract

Corrosion tests of Ni-based alloy Inconel 740H were carried out in supercritical carbon dioxide (S-CO 2 ) at 650-700°C under 25 MPa. The corrosion kinetics were measured by weight change as a function of time, and the surface oxide layers were characterised and identified by a series of characterisation methods. It is found that Inconel 740H experienced general oxidation, localised exfoliation and internal oxidation. A dense Cr 2 O 3 oxide scale rapidly formed on the surface of Inconel 740H at 650-700°C, resulting in good general corrosion resistance. Nodular oxidation was triggered by Tirich and Nb-rich oxides. Internal oxidation selectively oxidised Al. The causes of oxide-induced exfoliation are discussed.

Review on corrosion of alloys for application in supercritical carbon dioxide brayton cycle

“…In addition to Cr, Ni, and Al, some other alloying elements can also affect the corrosion behavior of alloys in S –CO 2 . The effects of Ti and Nb on the oxidation behavior of Inconel 740H in high-temperature and high-pressure S –CO 2 environments (650–750 °C, 25 MPa) were discussed [ 95 ]. Ti and Nb may form oxide nodules on the surface, which will accelerate the oxidation of the matrix.…”

Achieving High Strength and Creep Resistance in Inconel 740H Superalloy through Wire-Arc Additive Manufacturing and Thermodynamic-Guided Heat Treatment

“…Moreover, the reduction in the silicon, boron, and niobium content in Inconel 740H compared to the parent alloy maximized the weldability by decreasing the susceptibility to liquation cracking [4]. This alloy has been considered a suitable candidate for several power generation applications, such as thermal power plants with super-critical CO 2 [5] and concentrated solar power plants [6]. Inconel 740H in its wrought form has been investigated to determine several critical properties such as corrosion, oxidation, and fatigue resistance for its use in these applications [7][8][9][10].…”