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Al2O3 particle-modified Fe66Cr10Nb5B19 metallic glass matrix coatings were deposited on carbon steel substrates by detonation spraying of the corresponding powder mixtures. The microstructure, mechanical and tribological properties of the coatings were investigated. In the microstructure of the coatings, the Al2O3 particles were located between the layers of the Fe66Cr10Nb5B19 amorphous alloy. The bonding strength between the substrate and composite coatings was ~ 130 MPa. The wear behavior of the coatings was studied under dry linearly reciprocating conditions in a ball-on-flat mode using a WC-6Co ball as a counterbody. It was found that the friction coefficients of the Al2O3-free coating and composite coatings were close to each other and varied in the range of 0.64–0.70. The specific wear rate of the coatings modified with 1.5 and 4 vol.% of Al2O3 was 2.5 × 10−5 and 3.1 × 10−5 mm3 N−1 m−1, respectively, which is about one-fifth of the specific wear rate of stainless steel. It was suggested that the dominating wear mechanisms of the Fe66Cr10Nb5B19-Al2O3 composite coatings are fatigue and abrasion wear. [ABSTRACT FROM AUTHOR]

In the present work, Fe66Cr10Nb5B19 metallic glass coatings deposited by detonation spraying (DS) on carbon steel substrates were structurally characterized and tested in 3.5 wt.% NaCl solutions with pH values of 3.0, 5.5, and 10.0 under potentiodynamic polarization conditions. The coatings had low porosity (2.9-4.5%) and showed a predominantly amorphous structure. The concentration of an amorphous phase in the detonation coatings was 97.5-99.5 wt.%. Such high concentrations were not observed in thermally sprayed Fe-Cr-Nb-B coatings obtained by other research groups. Under the test conditions, the coatings exhibited low corrosion current densities (of the order of 10-6 A cm-2) and low passive current densities (below 10-3 A cm-2) while showing extended passive regions (stable within 1.5 V from the corrosion potential). The Fe66Cr10Nb5B19 coatings produced by DS showed a much better corrosion resistance than the carbon steel substrate. Furthermore, the corrosion resistance of the Fe66Cr10Nb5B19 DS coatings was superior to that of flame-sprayed or high-velocity oxygen fuel-sprayed Fe-Cr-Nb-B coatings reported to date. These results open new prospects for the use of affordable and Cr-lean Fe-Cr-Nb-B glassy coatings for carbon steel protection, where chloride-induced corrosion is the major degradation risk, such as metallic components for marine applications. [ABSTRACT FROM AUTHOR]