Research On Preparation And Failure Mechanism Of Corrosion Resistant High Performance Diamond-Like Carbon Film On HP-13Cr Steel Surface

As an oil well casing material,HP-13Cr super martensitic stainless steel is widely used in oil well exploitation and petroleum gas transportation industry.As the oil and gas field mining environment becomes more and more severe,the corrosive environment has caused a large number of material corrosion failure accidents.The two aggressive media,high Cl~-and sulfate reducing bacteria,have a particularly serious impact on steel corrosion failure.Therefore,improving the corrosion resistance and other mechanical properties of steel by preparing corrosion-resistant and high-performance thin film materials on the surface of HP-13Cr steel is of great significance to reduce the corrosion failure accidents of oil and gas field materials and the corrosion protection of oil pipe steel.In this paper,a plasma-enhanced chemical vapor deposition technology is used to prepare an amorphous diamond-like carbon film on the surface of HP-13Cr steel,which effectively improves the mechanical properties and corrosion resistance of the steel surface.The diamond-like carbon films with different pulse voltages and different substrate bias voltages were prepared,and the morphology,structure and mechanics of the films were measured by atomic force microscope,scanning electron microscope,Raman spectroscopy,infrared spectroscopy,nano indenter,scratch tester,friction and wear tester and other equipment.Performance characterization.The electrochemical workstation was used to characterize the corrosion behavior and failure mechanism of the film in a high Cl~-environment and a sulfate-reducing bacteria environment.The main conclusions of the research are as follows:During the increase of the pulse voltage,the ion energy increases,leading to the breaking of the C-H bond on the surface of the film and the phenomenon of hydrogen desorption in the film.During the dynamic friction process,the shear force will cause the film to appear local graphitization,which is manifested as a decrease in the friction coefficient.The maximum film thickness of the sample without substrate bias is 1.83?m,and the etching effect caused by the substrate bias will cause the loss of film thickness.The surface of the film with low incident carbon ion energy is granular,and the surface of the film with high carbon ion energy is clustered.The film prepared under pulsed conditions has the least sp~2 hybrid structure but the largest internal stress,the highest degree of matching with the substrate,and the largest membrane-base bonding force is 26.15N.The pores of diamond-like films are divided into through-type pores and closed-type pores.The film with through-type pores has flaky corrosion products after being immersed in a high Cl~-environment for 29 h.The film with closed pores formed pits after being immersed in a high Cl~-environment for 24 h.The DLC film with closed pores can effectively resist the erosion of Cl~-and play a role of corrosion protection.The adsorption of SRB bacteria will cause the positive shift of the open circuit potential of the sample.The formation of biofilm will increase the surface impedance of the sample.The hydrophobic sample SRB bacteria adsorb slowly,and the biofilm grows slowly,and the hydrophilic sample does the opposite.Microbial metabolites composed of carbon and oxygen-polysaccharides adhere to the surface of the sample.