FeCoCrNiMox composite powders were prepared using the mechanical alloying technique and made into high-entropy alloy(HEA)coatings with the face-centered cubic phase using plasma spraying to address the element segrega...FeCoCrNiMox composite powders were prepared using the mechanical alloying technique and made into high-entropy alloy(HEA)coatings with the face-centered cubic phase using plasma spraying to address the element segregation problem in HEAs and pre-pare uniform HEA coatings.Scanning electron microscopy,transmission electron microscopy,and X-ray diffractometry were employed to characterize these coatings’microstructure and phase composition.The hardness,elastic modulus,and fracture toughness of coatings were tested,and the corrosion resistance was analyzed in simulated seawater.Results show that the hardness of the coating is HV0.1606.15,the modulus of elasticity is 128.42 GPa,and the fracture toughness is 43.98 MPa·m^(1/2).The corrosion potential of the coating in 3.5wt%NaCl solution is-0.49 V,and the corrosion current density is 1.2×10^(−6)A/cm^(2).The electrochemical system comprises three parts:the electrolyte,the adsorption and metallic oxide films produced during immersion,and the FeCoNiCrMo HEA coating.Over in-creasingly long periods,the corrosion reaction rate increases first and then decreases,the corrosion product film comprising metal oxides reaches a dynamic balance between formation and dissolution,and the internal reaction of the coating declines.展开更多
Al_(2)O_(3)-Y_(2)O_(3) composite powder with TiO_(2) additive was plasma sprayed to prepare Al_(2)O_(3)-Y_(2)O_(3) composite coatings.The micro structure and properties evolution of the Al_(2)O_(3)-Y_(2)O_(3) coatings...Al_(2)O_(3)-Y_(2)O_(3) composite powder with TiO_(2) additive was plasma sprayed to prepare Al_(2)O_(3)-Y_(2)O_(3) composite coatings.The micro structure and properties evolution of the Al_(2)O_(3)-Y_(2)O_(3) coatings during high temperature and thermal shock resistance were investigated.The results show that the micro structure of the Al_(2)O_(3)-Y_(2)O_(3)-TiO_(2) coating is more uniform than that of the Al_(2)O_(3)-Y_(2)O_(3) coating.Meanwhile,amorphous phase is formed in the two coatings.The Al_(2)O_(3)-Y_(2)O_(3)(-TiO_(2)) coatings were heat treated for 2 h at temperatures of 800,1000 and 1200℃,respectively.It is found that the microstructure and properties of the two coatings have no obvious change at 800℃.Some of the amorphous phase is crystallized at1000℃,and meanwhile Y_(2)O_(3) and Al_(2)O_(3) react to form YAG phase and YAM phase.At 1200℃,all of the amorphous phases are crystallized.After heat treatment,the micro hardness of the two coatings is increased.The thermal shock resistance of the Al_(2)O_(3)-Y_(2)O_(3) system coatings can be improved by using TC4 titanium alloy as substrate and with NiCrAlY bonding layer.Moreover,the Al_(2)O_(3)-Y_(2)O_(3)-TiO_(2) coating exhibits better thermal shock resistance due to the addition of TiO_(2).展开更多
基金supported by the National Natural Natural Science Foundation of China(No.52271055)the Natural Science Foundation of Hebei Province,China(No.E2024202154).
文摘FeCoCrNiMox composite powders were prepared using the mechanical alloying technique and made into high-entropy alloy(HEA)coatings with the face-centered cubic phase using plasma spraying to address the element segregation problem in HEAs and pre-pare uniform HEA coatings.Scanning electron microscopy,transmission electron microscopy,and X-ray diffractometry were employed to characterize these coatings’microstructure and phase composition.The hardness,elastic modulus,and fracture toughness of coatings were tested,and the corrosion resistance was analyzed in simulated seawater.Results show that the hardness of the coating is HV0.1606.15,the modulus of elasticity is 128.42 GPa,and the fracture toughness is 43.98 MPa·m^(1/2).The corrosion potential of the coating in 3.5wt%NaCl solution is-0.49 V,and the corrosion current density is 1.2×10^(−6)A/cm^(2).The electrochemical system comprises three parts:the electrolyte,the adsorption and metallic oxide films produced during immersion,and the FeCoNiCrMo HEA coating.Over in-creasingly long periods,the corrosion reaction rate increases first and then decreases,the corrosion product film comprising metal oxides reaches a dynamic balance between formation and dissolution,and the internal reaction of the coating declines.
基金Project supported by the National Natural Science Foundation of China(51672067,51541208,51102074)the Natural Science Foundation of Hebei Province(E2018202034,E2015202070)+1 种基金the Foundation for Talent Training Project in Hebei Province(A2016002026)the Foundation for the Top Talents in Universities of Hebei Province(SLRC2017027)。
文摘Al_(2)O_(3)-Y_(2)O_(3) composite powder with TiO_(2) additive was plasma sprayed to prepare Al_(2)O_(3)-Y_(2)O_(3) composite coatings.The micro structure and properties evolution of the Al_(2)O_(3)-Y_(2)O_(3) coatings during high temperature and thermal shock resistance were investigated.The results show that the micro structure of the Al_(2)O_(3)-Y_(2)O_(3)-TiO_(2) coating is more uniform than that of the Al_(2)O_(3)-Y_(2)O_(3) coating.Meanwhile,amorphous phase is formed in the two coatings.The Al_(2)O_(3)-Y_(2)O_(3)(-TiO_(2)) coatings were heat treated for 2 h at temperatures of 800,1000 and 1200℃,respectively.It is found that the microstructure and properties of the two coatings have no obvious change at 800℃.Some of the amorphous phase is crystallized at1000℃,and meanwhile Y_(2)O_(3) and Al_(2)O_(3) react to form YAG phase and YAM phase.At 1200℃,all of the amorphous phases are crystallized.After heat treatment,the micro hardness of the two coatings is increased.The thermal shock resistance of the Al_(2)O_(3)-Y_(2)O_(3) system coatings can be improved by using TC4 titanium alloy as substrate and with NiCrAlY bonding layer.Moreover,the Al_(2)O_(3)-Y_(2)O_(3)-TiO_(2) coating exhibits better thermal shock resistance due to the addition of TiO_(2).
