Tribocorrosion Characteristics And Mechanism Of Typical Passivation Alloy In Simulated Seawater

As a strong corrosive medium,seawater is prone to equipment or parts failure due to material corrosion,causing hidden safety hazards,economic losses and even casualties.As the basis of marine engineering,the selection and application of materials are crucial.Passivated metals and alloys are widely used in the marine field because they can form a passive film on the surface to resist seawater corrosion,and they have become the most widely used marine engineering materials.However,passivation alloy structural components inevitably withstand mechanical effects such as friction during service,which can easily lead to material corrosion or sudden failure due to the destruction of the passivation film,which seriously affects the service life,safety and reliability of offshore equipment Nature,which poses serious challenges to marine engineering.Therefore,for the passive metals and alloys serving in the marine environment,it is very necessary to carry out research on their special capabilities and mechanisms under the synergy of tribocorrosion,so as to provide theory for the design and selection of marine engineering equipment,life assessment,and safety and reliability guarantee.Basis or practical guidance has important engineering practice value.In this paper,selected TC4 titanium alloy and 316L stainless steel which the typical passive alloy materials in marine engineering equipment applications as the main research objects.According to the principle of mechanical scratching,two sets of tribocorrosion experimental devices are designed and improved.Reasonably design the corresponding electrochemical corrosion circuit,carry out tribocorrosion experiments under different applied parameters and methods,explore the relationship between mechanical friction parameters and electrochemical corrosion parameters,and analyze the tribocorrosion of TC4 titanium alloy and 316L stainless steel in simulated seawater environment behavior.Observation of micro-morphology,combined with parameter data and micro-morphology,to study the tribocorrosion characteristics and mechanism of passive alloys under the synergistic effect of "electrochemical corrosion" and "mechanical friction".The main findings are as follows:(1)Record the mechanical and electrochemical parameter data during the experiment,combine the two parameter changes to analyze the effect of the applied conditions on the tribocorrosion performance of the passive alloy,and find that under different friction modes,as the friction load and speed increase,the corrosion behavior of the alloy exacerbate.Analysis of unidirectional tribocorrosion experiments revealed that there are differences in the effect of external parameters on the tribocorrosion properties of different passivation alloys.TC4 titanium alloy is more sensitive to friction load,and 316L stainless steel is more affected by friction speed.(2)Experimental analysis suggests that 60r/min is a dynamic equilibrium parameter that characterizes the "depassivation-repassivation" behavior of a type of passive alloy under unidirectional frictional motion.(3)There are differences in the corrosion and wear properties of passive alloys with different friction methods.Under the same conditions,reciprocating friction has a more serious effect on the corrosion and wear performance of the alloy than unidirectional friction,and the role of friction "third body" obvious.(4)The tribocorrosion mechanism of the passive alloy in simulated seawater was studied.The tribocorrosion mechanisms of the TC4 titanium alloy and 316L stainless steel samples were mainly abrasive wear,accompanied by corrosion wear and fatigue wear,and mechanical friction and corrosion were significantly promoted effect.On this basis,the tribocorrosion mechanism model of the passivation alloy is established.This model have certain theoretical guiding significance for the application of the passivation alloy as a marine engineering structural material.