| Corrosion wear is one of the main failure modes of metals in actual working conditions.As a key material used in some equipment exposed to corrosion,stainless steel is of excellent corrosion resistance.But it is often damaged by the combined effect of corrosion and wear.In this work the damage behavior of 304/430 stainless steels both in 0.5M sulfuric acid and deionized water was investigated under different loadings(30N.60N.90N)and frequencies(0.5Hz,1Hz,2Hz)by a reciprocating tribotester.To distinguish corrosion behavior of the stainless steels,polarization curve,electrochemical impedance spectroscopy(EIS)and re-passivation curve were measured by an electrochemical workstation.The surface and sectional morphologies of the wear scars were observed by a scanning electron microscope(SEM).The hardness of the sample surface and the wear scar section were tested by a microhardness tester.This is used to discuss the interaction between corrosion and wear of stainless steels in 0.5M sulfuric acid.The highlighted results are as follows:1)The wear test results of two stainless steels in deionized water show that wear loss of two stainless steel increases with the load,while the frequency has a minor effect on wear loss.The damage mechanism was abrasive wear,which mainly consisted of cutting,ploughing and plastic deformation.The wear resistance of 430 stainless steel is a little higher than that of-304 stainless steel,resulting from its good deformability and high thermal diffusivity.2)The wear test results of two stainless steels in 0.5M sulfuric acid show that damage loss of two stainless steel increases with the loading.The damage mechanism was abrasive wear.which mainly consisted of cutting ploughing,micro-fracture and peeling.The tribocorrosion resistance of 304 stainless steel is much higher than that of 430 stainless steel,resulting from the strong corrosion resistance of-304 stainless steel in 0.5M sulfuric acid.3)Friction factor of the two stainless steels is not related to the loading and frequency,but it is deeply dependent on environmental media.For 304 stainless steel,the friction factor was within the range 0.50-0.57 in distilled water,while it was within the range 0.30-0.35 in 0.5M sulfuric acid.For 430 stainless steel,the friction factor was within the range 0.55-0.65 in distilled water,while it was within the range 0.37-0.45 in 0.5M sulfuric acid.The friction factor is closely related to the status of the passivation film of stainless steels.4)The microhardness of the sample surface and the cross section of the wear scars was tested.The results indicated that work hardening occurred during the friction process.On the near surface(20-40 ?m),the average microhardness of 304 stainless steel was 3.3 GPa in 0.5 M H2SO4 and 3.7 GPa in distilled water.While for 430 stainless steel it was 1.46 GPa in 0.5 M H2SO4 and 1.57 GPa in distilled water.It can be inferred that hydrogen embrittlement not only reduces the subsurface strength of wear scars but also decreases the wear resistance of the stainless steels.5)For the two stainless steels there is an obvious interaction between corrosion and wear in 0.5M sulfuric acid,and the tribocorrosion loss mainly comes from the interaction between wear and corrosion.The interaction amount for 304 stainless steel accounts for 60%?95%of total damage,while it for 430 stainless steel accounts for 90%?99%of the total damage.The interaction amount mainly comes from the effect of wear to corrosion,which is related to the loading and test time. |
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