Fabrication, Wear Resistance And Non-skid Properties Of Fe-based Amorphous Coatings With Excellent Corrosion Resistance

The ship deck and offshore platform faced harsh working environment in the ocean, including sea water corrosion, sunshine insolate, impact wear and slippery surface.In order to overcome these disadvantages, organic and cermet coatings are used to achieve corrosion and wear resistance and anti-skid effect, but the performance is not significantly satisfied. Fe-based amorphous alloys with a good glass-forming ability have good performances, such as ultrahigh hardness, excellent wear and corrosion resistance, as well as low cost. Fe-based amorphous coatings prepared by thermal spraying retain the advantages of the corresponding bulk metallic glasses and are very promising for the application in this field due to the combination of a set of unique properties, including variable thickness, uniform microstructure and excellent adhesion.In this paper, the Fe49Cr17.8Mo7.2Mn18W1.6B15.4C4.6Si2.5 alloy with a good glass forming abilities was selected and the corresponding coating was successfully prepared by high velocity air-fuel (HVAF) and high velocity oxy-fuel (HVOF). The influence of the microstructure of coatings on oxidation and crystallization behavior were studied. Further, the microhardness and corrosion resistance of the coatings were evaluated in seawater. Meanwhile, the tribology behavior of coatings in dry condition, seawater and oily lubrication were investigated. The conclusions were summarized as follows:1. The coatings prepared by HVOF and HVAF exhibit combinations of uniform microstructure, very low porosity and oxygen content. Compared with the corresponding powder, the amorphous content of both coatings was significantly improved. The surface roughness is almost the same.2. The coatings prepared by HVOF and HVAF exhibit ultrahigh microhardness of about 1080 HV, which is apparently higher than that of 304 stainless steel. Both coatings exhibit good corrosion resistance in 3.5 wt.% NaCl solution with wide passive region and rather high pitting potential.However, the passivation current density of both coating is higher than that of the same compositional ribbon due to the existence of coating defects.3. Wear behavior of amorphous coatings was studied under dry sliding conditions in a ball-on-plate mode using GCr15 as the counterpart, both coatings exhibit high friction coefficient and excellent wear resistance. The wear volume of coatings is only about 1/6 of that of 304 stainless steel matrix. With the increase of the load, the friction coefficient and wear rate of coatings decreased, but wear volume and adhesion tendency increased. When the GCr15 and alumina balls were selected as counterpart, the dominant mechanism are adhesion and fatigue wear. The latter also accompanied with certain oxidation wear.4. When the alumina and GCr15 balls were selected as counterpart, compared with dry sliding condition, the total wear volume fall to 1/3 in artificial sea water and 1/5 in oily lubrication due to boundary lubrication. Similarly, the wear rate also increased with increasing the load but not obviously. And the dominant mechanism is fatigue wear. The latter also accompanied with certain oxidation wear.