Study On Flame Sprayed PEEK Coatings For Multi-substrate Used In Marine Environment

The report of the 19th National Congress of the Communist Party of China points out that China should accelerate the construction of a strong marine state.But at this stage,marine engineering and related building manufacturing industries are facing various challenges,marine engineering construction not only requires a large amount of capital and equipment investment,but also needs to take into account the service life of engineering buildings,especially the reason why the service life of marine engineering buildings is greatly shortened,corrosion of buildings in the marine environment has become increasingly important to people.At present,the most commonly used corrosion-resistant measures are the application of solvent-based anti-corrosion coatings,as well as coating curing methods such as electrostatic spraying,fluidized bed method,etc.However,the former organic solvent used will cause serious pollution to the marine environment,the latter is due to the need to use thermostat curing and volume constraints.Both methods used in the marine environment for building corrosion have many shortcomings.To overcome these shortcomings,the flame spraying method is used to prepare a multi-substrate corrosion resistant polyether ether ketone coating for the marine environment,which has the advantages of being solvent free and can be prepared as an indefinite volume product coating.Flame spraying is a technique that uses a flame as a heat source to heat the raw material for the coating to a molten or semi-molten state and then uses a high-speed airflow to spray the molten material onto the surface of the specimen to form a coating to obtain the corresponding surface properties.The flame spraying method was originally created to spray metal such as Ni,Fe,or metal compound powders such as Ti C^[1,2],but in the marine environment the metal powder coating itself would be corroded and unusable.Poly-ether-ether-ketone has excellent physicochemical properties and is environmentally friendly,so the use of flame spraying to prepare poly-ether-ether-ketone coatings has great promise in the field of metal and concrete protection in the marine environment.Combined with the characteristics of the marine environment,this paper uses the flame spraying method to prepare metal-based and concrete-based polyether ether ketone coatings in parallel research,giving full play to the advantages of the flame spraying method in terms of ease of operation,environmental protection and non-pollution,while also giving full play to the excellent performance of polyether ether ketone corrosion and wear resistance.The flame sprayed poly-ether-ether-ketone coating microscopically covers the capillary pore channels of concrete and macroscopically forms a continuous phase protective film on the surface,which can effectively block the penetration of water and ions and effectively extend the service life of the substrate.This thesis is based on the group’s research on polyether ether ketone coatings.Firstly,the possibility that polyether ether ketone coatings can adhere to concrete-based surfaces was demonstrated by using the coating cast method and the overlay moulding method,and then the optimum particle size for flame spraying polyether ether ketone powder was selected by combining morphological analysis to 650 mesh and the optimum process parameters such as spray air pressure,substrate preheating and spray distance for flame spraying polyether ether ketone coatings were investigated.In order to expand the scope of application of marine anti-corrosion and anti-seepage coatings,this thesis prepared polyether ether ketone coatings by flame spraying on metal substrates,using infrared thermography gradient control of substrate preheating temperature and improving the surface of the substrate by surface decontamination and sandblasting,and obtained the optimal process parameters for the preparation of metal-based coatings by adhesion grade testing for a preheating temperature of 350℃,a coating thickness of about 15.5μm with an adhesion grade of 0 The coating hardness is 2H and the coefficient of friction is 0.1802,and it can withstand neutral salt spray for more than 144h.The flame-sprayed metal-based poly-ether-ether-ketone coatings exhibit excellent hardness,friction resistance and resistance to bleeding and corrosion.The optimum process coating is then remelted by flame gun treatment to obtain a metal-based coating with better wear resistance and a coefficient of friction down to 0.1188.The optimum process parameters for the preparation of concrete-based coatings were further selected by a similar research method,with a preheating temperature of 350℃and a coating thickness of about 25.5μm.The optimum process parameters were a coating hardness of 2H,a coating adhesion class of 0 and a friction coefficient of0.3094.The total electrical flux of the concrete-based coating was measured by the chloride permeation flux method at 565C for 360 min,which is 76.7%lower than that of the uncoated concrete-based sample and is close to the performance of a solvent-based epoxy coating of three times the thickness（140μm）,indicating that the flame sprayed concrete-based poly-ether-ether-ketone The corrosion resistance of the coating was significantly enhanced.