Corrosion Mechanism of Inconel 600 in Oxidizing Supercritical Aqueous Systems Containing Multiple Salts

Abstract

The corrosion behavior and mechanism of Inconel 600 exposed to the oxidizing high-salinity supercritical water (SCW) containing chlorides, sulfates, and phosphates at 450, 500, and 580 °C were investigated and proposed. The corrosion film had an outer layer dominated by NiO, Fe 2 O 3 , and eutectic phosphate deposit and an inner layer consisting of Cr-rich oxides. Some produced oxides may generate ionic reactions with the low-melting phosphates precipitated out from SCW, triggering the generation of the eutectic FePO 4 − Ni 3 (PO 4 ) 2 −Na 3 PO 4 −Na 2 HPO 4 salts in the outer layer. The formation and thickening of the outer layer results from the eutectic phosphate disposition and the common solid-state growth mechanism. Nonmolten chlorides and sulfates in SCW predominantly exist on the outmost surface and are easily washed off, being supported by the absence of S and Cl on sample surfaces. Based on this investigation, a comprehensive corrosion mechanism, involving the solid-state growth of oxide scales, salt precipitation, and phosphate melting processes, was proposed and discussed.

Design and enhanced anticorrosion performance of a Zn5Mo2O11·5H2O/h-BN nanocomposite with labyrinth of nanopores

“…25 The broad peak at 700–1000 cm −1 of Zn 5 Mo 2 O 11 ·5H 2 O was due to the stretching vibration of [MoO y ] n − , and the peak at 472 cm −1 belonged to the Zn–O stretching vibration. 26,27 All characteristic peaks of h -BN and ZMO were present in the infrared spectrum of the ZMO/ h -BN composite, which confirmed the successful graft of ZMO on the surface of h -BN. 28 Moreover, in the spectrum of the ZMO/ h -BN composite, the peak of B–N–B at 819 cm −1 for h -BN decreased, confirming the chemical bonding between ZMO and h -BN.…”

“…The peaks of h-BN were observed at 819 cm −1 and 1378 cm −1 , which were attributed to B-N bending and B-N stretching, respectively 25. The broad peak at 700-1000 cm −1 of Zn 5 Mo 2 O 11 •5H 2 O was due to the stretching vibration of [MoO y ] n− , and the peak at 472 cm −1 belonged to the Zn-O stretching vibration 26,27. All characteristic peaks of h-BN and ZMO were present in the infrared spectrum of the ZMO/h-BN composite, which confirmed the successful graft of ZMO on the surface of h-BN 28.…”

Optimization and Mechanism Study on Destruction of the Simulated Waste Ion-Exchange Resin from the Nuclear Industry in Supercritical Water

“…A certain amount of the resin sample, hydrogen peroxide solution, and deionized water were added to the reactor and then the reactor was sealed by tightening the joint to seal after eliminating the air in the reactor by sweeping with helium for 5 min. It needs to be mentioned that, the amount of resin samples, oxidants, and deionized water were determined based on the reactor volume, experimental temperature, and pressure, which were verified repeatedly during preliminary tests . Then, the reactor was immersed into a preheated fluidized sand bath (Techne SBL-2D, Techne) with the temperature controlled by a temperature controller with a precision of 2 °C.…”

“…It needs to be mentioned that, the amount of resin samples, oxidants, and deionized water were determined based on the reactor volume, experimental temperature, and pressure, which were verified repeatedly during preliminary tests. 17 Then, the reactor was immersed into a preheated fluidized sand bath (Techne SBL-2D, Techne) with the temperature controlled by a temperature controller with a precision of 2 °C. A stopwatch was used for timing when the temperature in the reactor reached the predetermined reaction temperature.…”

Review on an Advanced Combustion Technology: Supercritical Hydrothermal Combustion

“…With the advancement of theoretical and experimental research on SCWO, its limitations begin to emerge. There are generally three major obstacles restricting the low-cost and reliable industrial implementation of SCWO technology: salt-deposition [6,7], corrosion [8][9][10] and high energy consumption. For traditional SCWO, raw materials need to be preheated to supercritical temperature.…”