Development of active thermochemical barrier coatings using metal oxides

Abstract

The use of Thermal Barrier Coatings (TBC) for protecting metallic components in diesel engines and gas turbines is very common.A new type of thermal coatings, the reactive thermal barrier coatings, involving reversible redox reactions is proposed in this study.. This new coating buffers the variation of temperature and reduces the thermal stress by dissipating the heat from the metallic component with the endothermic and exothermic thermochemical reactions.This paper deals with the development of this new kind of reactive thermal coatings using as thermochemical material cobalt oxide and nickel cobaltite pure and with addition of Si particles. For this purpose, a new application method has been developed by applying a mixture of sol-gel and thermochemical material by spray coating and ageing the layer by a CO2 solid-state laser.A deep research work has been carried out for the successful fabrication of thermal reactive coatings with three different formulations of thermochemical materials (Co3O4, Co2.4Ni0.6O4 and Co2.4Ni0.6O4 added with SiO2) obtaining homogeneous, stable and active coatings with good mechanical resistance.