Microstructure and tribological properties of iron-based metallic glass coatings prepared by atmospheric plasma spraying

• The compactness of iron-based coatings is ameliorated at elevated spraying power.
• The phase compositions of iron-based coatings include amorphous and crystalline structures.
• Iron-based coatings deposited at different spraying powers show similar steady-state friction coefficients.
• The wear rate of iron-based coatings varies with varying spraying power.

Iron-based metallic glass coatings (denoted as FeWCrNiMoBSiC) were prepared on 1Cr18Ni9Ti stainless steel cylinders by atmospheric plasma spraying at different parameters. The morphology, microstructure, and crystalline structure of as-prepared Fe-based metallic glass coatings were analyzed by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. A Pycnometer and a Vickers hardness tester were adopted to measure the porosity and microhardness of iron-based metallic glass coatings. Moreover, differential scanning calorimetry analysis was conducted to investigate the crystallization behavior of various iron-based metallic glass coatings, and a ball-on-disk tribometer was performed to evaluate the tribological properties of the coatings coupled with silicon nitride ceramic balls under unlubricated conditions. It has been found that the microhardness of iron-based metallic glass coatings increases with increasing plasma arc power, which is related to the degree of melting of feedstock powders and the compactness of as-prepared coatings. Besides, the phase compositions of as-sprayed coatings consist of amorphous structure and limited crystalline structure, and the contents of the amorphous structure and crystalline structure vary with plasma arc power. Moreover, iron-based metallic glass coatings deposited at different plasma arc powers show similar steady-state friction coefficients (0.8–0.9), but their wear rate varies with varying plasma arc power. Particularly, iron-based metallic glass coating with next to the highest hardness exhibits the best anti-wear ability, which is the outcome of the compromise between the hardness and brittle fracture as well as abrasive wear of the coatings during sliding process.