Study On Properties Of High-entropy Alloys Regulated By Little Atom C And N

Ocean transportation accounts for more than 2/3 of the total international trade volume.The proposal of the marine resource development strategy has further expanded the demand for marine service equipment.In the high humidity and high salt environment of the ocean,the key friction pair components are subjected to the dual effects of electrochemistry and friction,which accelerates the damage and failure of the components,resulting in a significant reduction in their service life.Therefore,research on surface protection materials with corrosion resistance and wear resistance in the harsh marine environment has become a top priority.Based on the four effects of high-entropy alloys and the modification of non-metallic small atoms,the various content of C and N modified VAlTiCrSi and VAlTiMoSi coatings under the protection of Ar gas were obtained by magnetron sputtering.The microstructure of the coatings with different C and N content and their friction and abrasion performance in artificial seawater environment were studied,and the chemical composition,microstructure,nano-hardness and elastic modulus of different coatings were tested.The inherent nature of good friction and abrasion properties to as-prepared coatings was revealed.What’s more,through the further analysis and characterization of the wear scar after the friction test,the tribological mechanism of different C and N contents was analyzed.Finally,through the heat treatment of the coating at 700℃,the microstructure change law,friction and electrochemical performance characteristics of the high entropy alloy coating after heat treatment were clarified.Based on the small size of C and N atoms,it is convenient to control the microstructure of materials,and the carbide has good friction properties,nitride can significantly improve the mechanical properties of the material,VAlTiCrSi,VAlTiCrSiC_x(x=1000 w,2500 w)and VAlTiCrSi N coatings have been prepared.By adjusting the coating power to adjust the percentage content of C and N atoms in the coating,the microstructure,hardness,elastic modulus and tribological properties of high-entropy alloy coatings with different C and N contents were studied.The results show that the VAlTiCrSi and VAlTiCrSiC_x coatings are both amorphous.The VAlTiCrSiC_x coating grows in a columnar shape.The dopenation of carbon makes the coating surface smooth and dense.The wear rate and friction coefficient of the VAlTiCrSi N coating are relatively high.The mechanism of wear and electro-chemistry has further studied by tribological and electrochemical tests.In order to explore whether C and N atoms affect the microstructure of high-entropy alloy coatings consistently,the VAlTiMoSi,VAlTiMoSiC_x(x=1000 w,2500 w)and VAlTiMoSi N coatings were prepared,and the percentage content of C and N atoms in the coating was adjusted by adjusting the coating power to study the microstructure,hardness,elastic modulus and tribological properties of N-content high-entropy alloy coating.The results show that the surfaces of the VAlTiMoSi,VAlTiMoSiC_x and VAlTiMoSi N coatings are all columnar growth,the VAlTiMoSi N coating is an FCC structure.The corrosion resistance mechanism of the coating was studied by electrochemical test of 3.5 wt%NaCl solution.Heat treatment is often used to improve the properties of materials,heat treatment of different coatings prepared,and explore the effects of annealing treatment on the microstructure,electrochemistry,friction and abrasion of the coating.The results show that after the film is annealed,the columnar structure becomes inconspicuous or even disappears,and the coating becomes denser.The heat treatment provides energy for the transformation of the crystal structure of the coating.The friction and corrosion mechanism of the coating after the heat treatment is studied by comparing the two coating systems longitudinally and vertically.