Study On Preparation And Properties Of Cu-Bearing Stainless Steel Marine Antifouling Coatings

Marine biofouling caused by undesirable adhesion of marine organisms on the surface of marine engineering equipment will not only bring security risks and economic losses,but also disturb the ecosystem,which has become an urgent problem to be solved in the application of marine engineering equipment worldwide.Cu ions have an effective killing effect on marine fouling organisms.Cu2O is used as an effective bactericidal component in Cu-bearing self-polishing antifouling coating which is widely used at present.However,it has the disadvantages of poor mechanical property and easy peeling.In addition,the Cu ion release rate of this type of coating is far beyond the critical release rate required for antifouling.The peeling coating in the polishing process will decompose into microplastics in seawater,seriously damaging the marine ecological environment.In recent years,it has been proposed to prepare pure Cu or Cu-bearing metal antifouling coatings by spraying on the surface of materials,and its adhesion strength and wear resistance have been significantly improved.However,the metal coatings containing Cu are all made of mechanically mixed powder,the distribution of Cu in the coatings is uneven,and the occurrence of random galvanic corrosion in the coatings reduces the possibility of controlling the Cu ion dissolution process,which still causes a huge burden to the marine ecology during the service process.Cu-bearing stainless steel is a kind of broad-spectrum antibacterial functional material which can regulate the amount of Cu ion leaching.It can effectively inhibit the formation of bacterial biofilm.Cu is uniformly distributed in the alloy material in the form of solid solution or second precipitated phase.Therefore,in this paper,the prealloyed powder of Cu-bearing stainless steel prepared by gas atomization method is selected as the spraying raw material,and the antifouling coating of Cu-bearing stainless steel is prepared by cold spray and high velocity air fuel spray.The microstructure,morphology,mechanical properties,electrochemical properties and antifouling properties of the coating prepared by mechanical mixed powder and commercial Cu-bearing self-polishing coating were studied,and the mechanism of antifouling performance of the coating was analyzed.Firstly,the antifouling coating was prepared by cold spray with the above mentioned two types of Cu-bearing stainless steel powder.The results show that the coating prepared by pre-alloyed Cu-bearing stainless steel powder has better corrosion resistance and lower Cu ion release rate due to its more uniform Cu distribution,which can effectively improve the service life of the coating.And reduce the damage to the marine ecological environment,compared with mechanical mixed powder,has more potential to become an environmentally friendly marine antifouling coating.However,the adhesion strength of the coating prepared by pre-alloyed Cu-bearing stainless steel powder is significantly reduced due to its poor plastic deformation ability.Therefore,it is necessary to further change the spraying method to improve the adhesion strength of the pre-alloyed antifouling coating.The preparation method of HVAF can make the powder particles in the process of spraying metallurgical bonding with the substrate,and improve the adhesion strength of the coating.Therefore,in order to further improve the adhesion strength of Cubearing stainless steel coating,the pre-alloyed Cu-bearing stainless steel coating was prepared by HVAF.The results show that the HVAF coating has higher adhesion strength and better wear resistance,and the corrosion resistance is slightly reduced.It has significant inhibition and killing effect on marine bacteria and algae,and can effectively inhibit marine biological fouling.The release rate of Cu ions did not increase significantly due to the decrease of corrosion resistance,which is friendly to marine ecological environment.In addition,its corrosion resistance is reduced so that it has better self-polishing performance,which can make the microorganisms killed on the surface and their secretions fall off from the surface of the material along with the corrosion products.With excellent antifouling performance,it has the potential to be widely used in marine engineering equipment to solve the problem of marine biological fouling.