Failure of boilers can cause huge economic loss to the power plants. In high temperature and aggressive working conditions erosion, hot corrosion and abrasions are most responsible factors for failure of boiler steels. Thermal spray coatings are the preferable method to minimize the cause of failures of the boiler steels due to these problems. Among different thermal spray techniques. By utilizing the HVOF process, it is possible to produce coatings with high micro-hardness and low porosity, making it an advanced and effective method that is currently undergoing rapid development. In this paper a review study regarding the performance of thermal spray coatings deposited on boiler steels against the hot corrosion has been presented. The outcomes of this research have the potential to assist in identifying the optimal coating combination and application technique to prevent the deterioration of boiler steels.