In this study,plasma shot(PS)treatment was applied to high-speed steel(HSS)surfaces using a titanium carbide electrode to confirm the effect of discharge current(Ip)on the formation of a single dimple and analyze a mo...In this study,plasma shot(PS)treatment was applied to high-speed steel(HSS)surfaces using a titanium carbide electrode to confirm the effect of discharge current(Ip)on the formation of a single dimple and analyze a modified layer.The roughness of modified surfaces increased when Ip increased,and energy-dispersive X-ray spectrometry showed an increase in titanium atom density whenIp and electrode consumption volume(Ve)increased.A friction test confirmed that the modified surface's friction was reduced by discharge dimples under low-load conditions.Vickers hardness test confirmed that the hardness of the modified surface was-300-600 HV higher than that of an untreated HSS surface.Moreover,it increased with an increase inIp.However,application of PS treatment to the edge of surfaces on the workpiece caused shape deterioration.The deterioration size of the edge of the modified layer increased when Ip increased.To solve this issue,we propose a novel method named position-adjusted PS(PA-PS)treatment.PA-PS treatment is used to adjust the end of the electrode in the order of tens of micrometers from the edge of the workpiece to avoid the deterioration of the edge form.Under Ip=21 A,PA-PS formed a modified layer without deteriorating the edge shape of the workpiece,thus confirming the PS characteristics applied to HSS surfaces.Moreover,PA-PS treatment solved the shape deterioration of the edge on modified surfaces via PS treatment.展开更多
An ODS （oxide dispersion strengthened） steels are one of the most notable structural materials being developed for future high-temperature energy production technologies, and several studies have been devoted to the...An ODS （oxide dispersion strengthened） steels are one of the most notable structural materials being developed for future high-temperature energy production technologies, and several studies have been devoted to the development of ODS materials for such applications. However, only little paper focuses on corrosion behavior of F/M （ferritic martensictic） and ODS steels. The corrosion behavior of 11% Cr F/M steel and 15% Cr ODS steel were evaluated using electrochemical methods in borate buffer and 1 kmol m＂3 HNO3 with or without NaCI and also in boiling 60% nitric acid. The corrosion resistance results clearly indicated the influences of steel alloys composition and chloride ions. The XPS （X-ray photo-electron spectroscopy） results of the pre-passivated surface revealed that the oxide formed were composed predominantly of Fe203 along with Cr203, and Y203 layers in ODS steel. The corrosion rate measured in boiling nitric acid for 48 h for both the steels shows high corrosion rate in boiling condition. The SEM （scanning electron microscopy） observation of the pit morphology after corrosion tests appears with shallow pit in both steel surfaces The corrosion degradation behavior in relation to the composition of the passive oxide film in different electrolytic solutions is discussed in this paper.展开更多
Independent microstructures made of Ni metal were fabricated by fivesequential processes: porous anodic oxide film formation, pore sealing, laser irradiation, Nielectroplating, and removal of the aluminum substrate an...Independent microstructures made of Ni metal were fabricated by fivesequential processes: porous anodic oxide film formation, pore sealing, laser irradiation, Nielectroplating, and removal of the aluminum substrate and anodic oxide films. Aluminum plates androds were anodized in an oxalic acid solution to form porous type anodic oxide films, and thenimmersed in boiling distilled water for pore sealing. The anodized and pore-sealed specimens wereirradiated with a pulsed neodymium-doped yttrium aluminum garnet (Nd-YAG) laser beam in a Ni platingsolution to remove anodic oxide film locally by rotating and moving up I down with anXYZ(theta)-stage. Nickel was deposited at the area where film had been removed by cathodicpolarization in the solution before removing the aluminum substrate and anodic oxide films in NaOHsolutions. Cylindrical or plain network structures were fabricated successfully.展开更多
文摘In this study,plasma shot(PS)treatment was applied to high-speed steel(HSS)surfaces using a titanium carbide electrode to confirm the effect of discharge current(Ip)on the formation of a single dimple and analyze a modified layer.The roughness of modified surfaces increased when Ip increased,and energy-dispersive X-ray spectrometry showed an increase in titanium atom density whenIp and electrode consumption volume(Ve)increased.A friction test confirmed that the modified surface's friction was reduced by discharge dimples under low-load conditions.Vickers hardness test confirmed that the hardness of the modified surface was-300-600 HV higher than that of an untreated HSS surface.Moreover,it increased with an increase inIp.However,application of PS treatment to the edge of surfaces on the workpiece caused shape deterioration.The deterioration size of the edge of the modified layer increased when Ip increased.To solve this issue,we propose a novel method named position-adjusted PS(PA-PS)treatment.PA-PS treatment is used to adjust the end of the electrode in the order of tens of micrometers from the edge of the workpiece to avoid the deterioration of the edge form.Under Ip=21 A,PA-PS formed a modified layer without deteriorating the edge shape of the workpiece,thus confirming the PS characteristics applied to HSS surfaces.Moreover,PA-PS treatment solved the shape deterioration of the edge on modified surfaces via PS treatment.
文摘An ODS （oxide dispersion strengthened） steels are one of the most notable structural materials being developed for future high-temperature energy production technologies, and several studies have been devoted to the development of ODS materials for such applications. However, only little paper focuses on corrosion behavior of F/M （ferritic martensictic） and ODS steels. The corrosion behavior of 11% Cr F/M steel and 15% Cr ODS steel were evaluated using electrochemical methods in borate buffer and 1 kmol m＂3 HNO3 with or without NaCI and also in boiling 60% nitric acid. The corrosion resistance results clearly indicated the influences of steel alloys composition and chloride ions. The XPS （X-ray photo-electron spectroscopy） results of the pre-passivated surface revealed that the oxide formed were composed predominantly of Fe203 along with Cr203, and Y203 layers in ODS steel. The corrosion rate measured in boiling nitric acid for 48 h for both the steels shows high corrosion rate in boiling condition. The SEM （scanning electron microscopy） observation of the pit morphology after corrosion tests appears with shallow pit in both steel surfaces The corrosion degradation behavior in relation to the composition of the passive oxide film in different electrolytic solutions is discussed in this paper.
文摘Independent microstructures made of Ni metal were fabricated by fivesequential processes: porous anodic oxide film formation, pore sealing, laser irradiation, Nielectroplating, and removal of the aluminum substrate and anodic oxide films. Aluminum plates androds were anodized in an oxalic acid solution to form porous type anodic oxide films, and thenimmersed in boiling distilled water for pore sealing. The anodized and pore-sealed specimens wereirradiated with a pulsed neodymium-doped yttrium aluminum garnet (Nd-YAG) laser beam in a Ni platingsolution to remove anodic oxide film locally by rotating and moving up I down with anXYZ(theta)-stage. Nickel was deposited at the area where film had been removed by cathodicpolarization in the solution before removing the aluminum substrate and anodic oxide films in NaOHsolutions. Cylindrical or plain network structures were fabricated successfully.
