Behaviour of cold sprayed superalloy in incinerator at 900°C

Materials and Manufacturing Processes

Sidhu²,

Kalsi

et al. 2015

The cold spray technique is still in its innovation stage. This process is similar to other thermal coating techniques with the additional benefit of lower working temperature than the melting energy of the feedstock material. In this study, a new coating-substrate system is developed by using the 80%Ni-20%Cr feedstock powder sprayed by this technique on a superni 601 superalloy substrate. The coating microstructure depends upon both the substrate and coating material properties, and thus, coating obtained in this study has a unique microstructure. The coating microstructure developed and tested in this study by scanning electron microscopy/energy-dispersive x-ray spectroscopy (SEM/EDX) and X-ray diffraction (XRD) techniques is found to be suitable for boilers and incinerators. INTRODUCTIONThe cold spray coating deposition technique is a relatively new member of the thermal spray family but with the added advantage that coating particles remained in the solid state in the as-sprayed coating [1][2][3][4][5][6][7][8][9][10][11][12]. This property of the cold spray process prompted the authors to develop and study the new coating-substrate system by this process for different applications, especially for corrosive environments at temperatures near to 900 C. The study related to the cold spray process is reported in detail in the earlier publications of the authors [8,9].The base material chosen in this study for cold spraying (superni 601 grade superalloy) is for providing strength to the newly developed system, at high working temperature of boilers and incinerators. The 80Ni-20Cr (wt.%) coating composition is selected for providing elements for the formation of the corrosion resistant oxide scale at high operating temperature. Though, the coating composition is good enough for the corrosive environment, the composition is not a sole criterion for providing effective corrosion protection. The development of the required coating microstructure is equally important for this purpose. The microstructure of the coating should be able to block the transport of ionic species and elements from both the environment and the substrate. If the microstructure is not good enough,

Section: Introductionmentioning

confidence: 99%

Evolution of the Microstructure by High Velocity Impacts of Particles by Cold Spray

Materials and Manufacturing Processes

Sidhu²,

Kalsi

et al. 2015

“…23,24 The roughness value measured for cold sprayed Ni-50Cr coating is comparatively similar to that reported in earlier publications for coatings that are able to be sustained in the erosive-corrosive environment of waste incinerators. [24][25][26] This shows that the Ni-50Cr coating is smooth enough for application in waste incinerator conditions. The coating smoothness is the result of plastic deformation of the cold sprayed particles because of high energy strikes during cold spraying.…”

Section: Resultsmentioning

confidence: 84%

Microstructure study of cold sprayed 50%Ni–50%Cr coating on Inconel-601

Sidhu²,

Kalsi

2015

Surface Engineering

Self Cite

A superalloy surface is modified with corrosion resistant 50%Ni-50%Cr (wt.%) coating, deposited by high pressure cold spray method. The goal of this study is to check the suitability of this cold method of coating formation as a manufacturing source for Ni-Cr coating on the superalloy for applications in high temperature erosive-corrosive conditions. The modified superalloy surface is characterised by porosity analysis, scanning electron microscopy, backscattered electron images, energy dispersive X-ray spectroscopy, elemental X-ray mapping and Vicker's microhardness testing techniques. The substrate superalloy with composition similar to Inconel-601 alloy (UNS no. N06601) is selected for the purpose of providing strength to the coated components in the severe conditions at elevated temperature.

“…This method is considered to be noble one amongst all members of thermal spray family because of spraying conditions at extreme low temperature. Temperature during cold spraying technique remains lower than the melting point of feedstock material, which further reduces the oxidation rate of powder particles to minimum [1-27]. For applications in boilers and incinerator components, coatings with low oxide levels are required which is difficult to achieve by traditional high-temperature spray methods because of rapid oxidation of coating particles during spraying process.…”

Section: Introductionmentioning

confidence: 99%

Characteristic study of cold sprayed N06601 superalloy surface

Khosla

Walia

et al. 2018

Surface Engineering

The surface properties of metals and alloys are usually altered by spray coating techniques for better performance in extreme conditions such as: erosive-corrosive and wear applications. In this study a wear and corrosion resistant coating composition of 75% Cr 3 C 2 -25% (Ni-20%Cr) was selected for cold spraying on N06601superalloy which can sustain in high-temperature applications. Microstructure properties of cold sprayed coating depend upon the composition and mechanical-physical properties of both coating and substrate materials, and cold spraying of brittle carbide-based materials is still a challenge for researchers. Various spray parameters were adjusted in this study to produce a 289 µm thick, smooth and dense (porosity less than 1) cold sprayed coating on 601-alloy with high hardness of 866 HV. For mitigating the erosion-corrosion phenomenon the coating microstructure is as important as its composition. This coating structure is suitable for further testing in high temperature and extreme corrosive conditions.