Contact: Olha Aleksieieva

Funding: Marie Skłodowska-Curie Actions (EU)

During the operation of thermal process equipment, the properties of its key components, namely refractory constructions, change due to the penetration of gaseous and liquid products into the surface layer and deep into the volume through pores. This leads to erosion and wear of the constructions, continuous emissions of polluting gases, and heat losses. A potential solution to this challenge is to develop a method to coat porous refractory structures with ceramic particles, which will protect the surface during equipment operation. This project aims to investigate the mechanisms of coating formation on porous surfaces and to develop an application technique by adapting a cold spray process (CS). In the developed CS process, ceramic microparticles are accelerated to supersonic velocities (up to 800 m/s) in a gas stream (nitrogen) by a Laval nozzle, sprayed onto the refractory surface and embedded into the surface by impact forming a strong bonding. The research investigates the particle spraying processes on porous surfaces both experimentally and through numerical simulations. The characteristics of the coating are determined by the complex interplay of transport phenomena in the aerosol, including the acceleration of particles within the jet, as well as material deformation and adhesion during particle impact on the surface and previously deposited particles.  The surface properties, such as porosity, permeability, and hardness, are analysed using scanning electron microscopy, computed microtomography and nanoindentation. CFD simulation with Lagrangian particle tracking was used to estimate the process parameters of the aerosol flow through the Laval nozzle and their movement in pores.