Microstructure and High Temperature Corrosion Behavior of Wire-Arc Sprayed FeCrSiB Coating

Abstract

Nowadays, wire-arc spraying is an attractive technique to deposit coatings for oxidation and corrosion protection. In this study, a new FeCrSiB-cored wire was designed to produce protective coatings for the components used in high temperature environment by wire-arc spraying. The microstructure, phase composition, microhardness, and high temperature corrosion behavior of the new coating were investigated in comparison with a FeCr coating and a commercial NiCrTi coating. The results showed that the FeCrSiB coating was composed of dense lamella with much fewer oxide inclusions than the FeCr and NiCrTi coatings. The microhardness of the FeCrSiB coating was the highest of the three coatings. Thermogravimetric analysis was used to evaluate the high temperature corrosion behavior of the coatings in mixed salt Na 2 SO 4 -25% K 2 SO 4 environment at 650°C under cyclic condition. It showed that the high temperature corrosion resistance of the FeCrSiB coating is significantly better than that of the FeCr coating and approaching to the commercial NiCrTi coating.

High-temperature erosion of Fe-based coatings reinforced with cermet particles

“…2 a – c ), which were associated with the shrinkage of the molten splats after deposition onto the substrate. 19,32,33 The reinforcement particles were fractured characteristically to the HVOF process, 23 and the resulting fragments were dispersed in the matrix, although the size of these fragments was remarkably higher in the case of the WC–Co reinforcement. Apart from fracture and dispersion, decrease in the reinforcement content in comparison with the initial feedstock powders was registered.…”

“…One of the most widespread protection approaches is the application of a thermally sprayed coating. 6,12,13 Commonly, borides, 14 cermets 6,15 and stellites, 4,16 as well as nickel-based 8,10,17,18 and iron-based 13,19,20 alloys are applied as coating materials. The last group of alloys is gaining increasing attention because of their good mechanical properties 21-24 and their relatively low price.…”

A Review on the Wear, Corrosion and High-Temperature Resistant Properties of Wire Arc-Sprayed Fe-Based Coatings

“…Guo et al [94] studied the hot corrosion resistance of FeCrBC in a mixed solution of Na 2 SO 4 + K 2 SO 4 (7:3) at 700 • C for 156 h. Thin films of Cr 2 O 3 formed on the coating and separated the alloy from the mixed salt solution, thus providing better resistance to hot corrosion. In a comparison study by Li et al [11], the arc-sprayed FeCrSiB coatings provided better hot corrosion resistance than FeCr, approaching that of NiCrTi coating. The weight gain for the hot corrosion has been calculated as follows:…”

“…Cr 3 C 2 in the cored wire improved the coating bond strength and facilitated formation of Cr 2 O 3 and Al 2 O 3 oxides, which increased the high-temperature resistant properties. To enhance the high-temperature and corrosion properties, Cr is widely used in Ni-based and Fe-based alloys because it forms the protective Cr 2 O 3 oxide layer [11]. Ni-based coatings are preferred due to their outstanding properties in high temperatures to prevent sulfidation and oxidation of the substrate.…”

Preparation of Ti-Al-Si Gradient Coating Based on Silicon Concentration Gradient and Added-Ce

“…Thermal corrosion is a phenomenon in which oxygen and other corrosive gases work together with salts deposited on the surface of materials in a hightemperature environment to accelerate corrosion, and its harmfulness is much greater than thermal oxidation. In addition, the research on high-temperature thermal corrosion resistance of high-temperature coatings in service above 1000 • C will be the focus of research in the future [4]. Therefore, in order to further improve the thrust-weight ratio of aero-engines and meet the requirements of materials for high-performance aero-engines, it is imperative to develop a new high-temperature titanium alloy coating with higher operating temperature.…”