Effect Of Alloying On Corrosion Resistance Property And Wear Resistance Property Of FeCoCrMoCBY BMGs

In this paper, Fe41Co7Cr15Mo14C15B6Y2 (BMG1), Fe41.9Co6.3Cr15.7Mo12.6C13.5B7.7Y1.8Ni0.5 (BMG2),Fe41.7Co6.3Cr15.7Mo12.6C13.5B7.7Y2Ni0.5 (BMG3), Fe40.4Co6.3Cr15.7Mo14C13.5B7.7Y2 (BMG4) Fe40.7Co6.3Cr16.7Mo12.6C13.5B7.7Y2Ni0.5(BMG5), Fe41Co7-xSixCr15Mo14C15B6Y2 (x=1,2, 3, BMG6, BMG7, BMG8) bulk metallic glass alloys were fabricated using the WK-? non-consumable type vacuum arc melting furnace water-cooled copper mold suction casting method. The structure of the bulk metallic glass alloys was characterized by X-ray diffraction (XRD). The corrosion resistance and passive film densification of Fe-based bulk metallic glass were tested by electrochemical technology. WTM-2E abrasion machine was employed to evaluate dry sliding friction and wear of Fe-based BMGs. The corrosion morphology and abrasion morphology were observed by scanning electron microscopy(SEM), and the composition of the passivation film was detected by energy disperse spectroscopy(EDS) and X-ray photoelectron spectroscopy(XPS). The article focus on the corrosion behavior of Fe-based BMGs after dopping alloy system and adding Si element in NaCl and HCl solution. The relationshop between YCr/Mo and passivation current density has been discussed. The effect of the Fe-based BMGs passive film composition after doping alloy system on the corrosion resistance has been studied. And the effect of Si element addition on passive film densification has been researched based on the point defect model (PDM). Additionally, the wear resistance and the abrasion mechanism of BMG1, BMG2, BMG3, BMG6, BMG7, and BMG8 alloys have been investigated.BMG1-BMG5 bulk metallic glass alloys show the same laws of corrosion resistance in HCl and NaCl solution. The corrosion resistance declines in the following order, BMG5?BMG3>BMG4>BMG1>BMG2. The electrochemical tests in 3% NaCl solution demonstrate that the passive current density has decreased with the increase of the YCr/Mo value. The fitting result shows that the logarithm of passive current density(?) and the YCr/Mo value(X) are in accordance with logarithmic relationship in 3% NaCl solution. When YCr/Mo value is over 2.3, passive current density of Fe-based BMGs becomes stable in 3% NaCl solution. The main component of Fe-based BMGs passive film formed in 3% NaCl solution is the oxide of Cr, Mo. When the YCr/Mo value is higher, the low-valence Fe2+, Cr3+, and Mo4+ ion is enriched more easily, which result in smaller passivation current density and more stable passive film. The dry sliding friction and wear results show that the coefficient of wear of BMG2 alloy with low hardness is the biggest resulting in the worst wear resistance, and wear mechanism of BMG2 alloy mainly is abrasive wear; the coefficient of wear of BMG1 alloy is between BMG2 and BMG3, the wear mechanism of BMG1 mainly is fatigue wear; the coefficient of wear of BMG3 is the least and the wear resistance is the best, the wear mechanism of BMG3 mainly is fatigue wear.The corrosion resistance of Fe4iCo7-xSixCr15Mo14C15B6Y2 (x=0,1,2,3, BMG6, BMG7, BMG8) bulk metallic glass in HC1 and NaCl solution is consistent. The corrosion resistance of those alloys declines in following order, BMG7>BMG8> BMG6>BMG1. With the addition of Si element, the passivation current density of the alloys reduces suddenly due to the formation of passive film with Si element resulting in the improvement of corrosion resistance. Based on M-S experiment result and the point defect model (PDM), the passive film of BMG1, BMG6, BMG7 and BMG8 alloys presents n-type semiconducting behavior. With the addition of Si element, the point defect density in passive film decreases and the passive film become more compact. The dry sliding friction and wear results of Fe41Co7-xSixCr15Mo14C15B6Y2 (x=0,1,2,3) alloys show that with the increasing of Si element coefficient of wear of alloys increase and the wear resistance decrease. The wear mechanism of BMG1 without Si element mainly is fatigue wear, while adhesive wear occurs for the alloys with Si element. With the increasing of Si content, the ability to resist adhesive wear decreses. The wear mechanism of BMG6 alloy is mainly abrasive wear, accompanying adhesive wear. Fatigue wear and adhesive wear are the main wear mechanism of BMG7 alloy. The adhesive wear was the dominant wear mechanism of BMG8.