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Cold spray evaluation programme success with Ansaldo Energia

A programme of work to evaluate cold spray technology in collaboration with Italian power engineering company Ansaldo Energia has demonstrated the process to be a viable alternative to Low Pressure Plasma Spray (LPPS) or Vacuum Plasma Spray (VPS).  Ansaldo Energia has since adopted cold spray in place of VPS for use in gas turbine blades, and the work has shown the potential for the use of the coating in critical applications across the power, oil and gas and aerospace industries.

The project team experimented with cold spray on discs using fine and coarse MCrAIY+Re powder coatings, deposited using the Kinetiks® 4000/47 cold spray system at a feed rate of 2.0kg/h and 1.9kg/h respectively.  Scanning the spraying gun over the discs for a total of four passes, the team was able to demonstrate a coating thickness of ~250µm.

Cold spray technology proves effective for Ansaldo Energia
Cold spray technology proves effective for Ansaldo Energia

The cold spray system housed at TWI is capable of spraying at gas pressures and temperatures of 40bar and 800°C, respectively. Mounted on a six-axis robot to allow accurate control of the spraying pattern, the system deposited coatings for this study using oxygen-free nitrogen as both a process and powder carrier gas, and using parameters based on those previously assessed by TWI for deposition of Ni-based alloys such as Ni625. Following spray deposition, the disc samples (coating plus substrate) were diffusion heat treated under vacuum at Ansaldo Energia.

In analysis, the fine powder spray achieved an efficiency of 33%, with the coarse powder achieving 31%. An examination of surface morphology showed that the cold spray coatings also had smoother surfaces than those coated through LPPS. As this was a limited study, results demonstrated no obvious correlation between powder particle size distribution, deposit efficiency and coating microstructure over the study range. However, the coating evolution study, coating degradation through testing in static air at high temperature, and coating consumption when compared with a VPS coating of the same composition, showed the cold spray process to be a more robust, longer-lasting alternative for the company. 

For further information, please see the surfacing and coating section of our website or email

Surface morphology of LPPS coating
Surface morphology of LPPS coating

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