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In order to further improve the wear resistance of Fe-Cr-C surfacing alloy, Fe-Cr-C wear-resistant surfacing alloy layers with different B addition amounts were prepared on the surface of Q235 steel by adjusting the amount of ferroboron powder added to the surfacing alloy powder using plasma powder surfacing technology.The effects of B addition amount on the microstructure, phase composition and wear resistance of Fe-Cr-C surfacing alloy were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), abrasive wear tests and other analysis and testing methods.Results showed that when the addition amount of B was 0, the microstructure of the surfacing alloy was composed of dendritic Fe and chrysanthemum-like (Fe, Cr)7(C, B)3＋Fe eutectic structure.With the increase of B addition amount, the volume fraction of the (Fe, Cr)7(C, B)3 hard phase in the surfacing layer increased.After the precipitation amount of the (Fe, Cr)7(C, B)3 phase reached a certain value, the primary B0.7Fe3C0.3 phase was formed.When the B addition amount was 20.0%(mass fraction), a large amount of the (Fe, Cr)2 B hard phase was precipitated.The hardness of the surfacing layer showed an overall trend of rising-steep drop-rising, and the hardness of the B-10 sample reached 63.1 HRC.The results of the abrasive wear test showed that the wear resistance of the surfacing alloy layer exhibited an trend of upward-flat- upward, and the wear resistance of the B-20 sample increased to 2.8 times that of the B-0 sample.

Natural edible films have recently gained a lot of interests in future food packaging. Polysaccharides and proteins in edible materials are not toxic and widely available, which have been confirmed as sustainable and green materials used for packaging films due to their good film-forming abilities. However, polysaccharides and proteins are hydrophilic in nature, they exhibit some undesirable material properties. Cold plasma (CP), as an innovative and highly efficient technology, has been introduced to improve the performance of polysaccharides and proteins-based films. This review mainly presents the basic information of polysaccharides and proteins-based films, principles of CP modified biopolymer films, and the effects of CP on the structural changes including surface morphology, surface composition, and bulk modification, and properties including wettability, mechanical properties, barrier properties, and thermal properties of polysaccharides, proteins, and polysaccharide/protein composite-based films. It is concluded that the CP modified performances are mainly depending on the polysaccharides and proteins raw materials, CP generation types and treatment conditions. The existing difficulties and future trends are also discussed. Despite natural materials currently not fully substitute for traditional plastic materials, CP has exhibited an effective solution to shape the future of natural materials for food packaging. [ABSTRACT FROM AUTHOR]