Research On The Preparation Of High-Temperature And Temperature Shock Resistance Potassium Silicate Coating

High-temperature resistant coating is one of the hot topics in the field of surface technology and coating material.It has been widely used in aerospace,high power engine and military equipment support and so on.With the development of industry,the environment of the working substrate needs thermal resistance coating protection.However,the organic coating can not meet the requirements.Further,many working environments are not a simple uniform high temperature,they have a sharp change of temperature sometimes,For example,the temperature of the aero-engine can reach 700°C⁹00°C in an instant,when the engine stops working,it quickly drops to room temperature,which results in the coating peal off.Therefore,the coating not only has the requirement of good high-temperature resistance,but also has the excellent thermal shock resistance.Aquosity inorganic silicate coating has the benifit of pollution-free,high hardness,weather resistance,contamination resistance,solvent resistance and long-term heat resistance,etc.However,the poor water resistance limits the further application of silicate coatings.In this thesis,aquosity inorganic thermal shock resistant coatings were prepared by using potassium silicate as film forming material.The water resistance of the coating was solved,the formulation and preparation process of the coating were discussed,the high-temperature and thermal shock resistance of the coating were studied.Firstly,the water resistance of the coating was enhanced by modified potassium silicate solution,including inorganic acid,silica sol,organic solvent and curing agent modification.Inorganic acid modification was easy to generate silicic acid and precipitate.Silica sol modification was easy to agglomerate because the pH of potassium silicate solution is more than 12 and colloidal particles are charged.Organic solvent modification can not meet the requirement of high temperature resistance of coating.Curing agent modification can ensure the stability of the system and the high temperature resistance of the coating.The water resistance of the coating was improved by using 5wt%silicon phosphate.Secondly,high temperature and thermal shock resistant coatings were prepared by curing agent modified potassium silicate solution,as film forming material which has the modulus of2.4,TiO₂ as pigment,MgO,Al₂O₃ and ZrO₂ as filler.The formula of the coating was confirmed by studying the composition and proportion of the coating.The coating with good high-temperature and thermal shock resistance at 800°C was obtained by studying the ball milling and solidify technology.Finally,the high-temperature and thermal shock resistance of potassium silicate coating reinforced by glass powder was studied.The effect of glass powder of different systems on the properties of the coating was studied.It was found that the high temperature resistance of the coating was greatly improved by the silicon-boron glass powder.The effect of different composition and content of silicon-boron glass powder on the properties of the coating was studied.The results show that the coating has good thermal shock resistance at 900°C by adding 10wt%glass powder E.