A low-diffusion Ni Re Pt Al coating((Ni,Pt)Al outer layer in addition to a Re-rich diffusion barrier layer)was prepared on a Ni_(3)Al-base single crystal(SC)superalloy via electroplating and gaseous aluminizing treatm...A low-diffusion Ni Re Pt Al coating((Ni,Pt)Al outer layer in addition to a Re-rich diffusion barrier layer)was prepared on a Ni_(3)Al-base single crystal(SC)superalloy via electroplating and gaseous aluminizing treatments,wherein the electroplating procedures consisted of the composite deposition of Ni-Re followed by electroplating of Pt.In order to perform a comparison with conventional Ni Al and(Ni,Pt)Al coatings,the cyclic oxidation performance of the Ni Re Pt Al coating was evaluated at 1100 and 1150℃.We observed that the oxidation resistance of the Ni Re Pt Al coating was significantly improved by the greater presence of the residualβ-Ni Al phase in the outer layer and the lesser outward-diffusion of Mo from the substrate.In addition,the coating with the Re-rich diffusion barrier demonstrated a lower extent of interdiffusion into the substrate,where the thickness of the second reaction zone(SRZ)in the substrate alloy decreased by 25%.The mechanisms responsible for improving the oxidation resistance and decreasing the extent of SRZ formation are discussed,in which a particular attention is paid to the inhibition of the outward diffusion of Mo by the Re-based diffusion barrier.展开更多
<div style="text-align:justify;"> The discovery of Earth’s radiation zone divided into two belts is the first major discovery in Human space exploration. The inner belt dominated by energetic protons ...<div style="text-align:justify;"> The discovery of Earth’s radiation zone divided into two belts is the first major discovery in Human space exploration. The inner belt dominated by energetic protons and the outer belt dominated by energetic electrons imply the inner belt with net positive charge and the outer belt with net negative charge. Earth’s surface carries net negative charge. These exploration data suggest the inner and outer parts of a star may be composed of several discrete charged layers. We propose the mechanism of the star’s multiple Debye spherical layers to adapt to the objective existence. The charged particles in the near-earth space follow the statistical distribution of multiple Debye spherical layers of Earth. The inner belt and outer belt is the main body of layer 8 and layer 9 respectively. The empty slot between the inner and outer belt comes from the action of the electric field between them. An impenetrable barrier to ultra-relativistic electrons originates from the action of the electric field of layer 7. </div>展开更多
基金the Key-Area Research and Development Program of Guangdong Province(2019B010936001)financially supported by the National Natural Science Foundation of China(Grant Nos.51671202 and 51301184)。
文摘A low-diffusion Ni Re Pt Al coating((Ni,Pt)Al outer layer in addition to a Re-rich diffusion barrier layer)was prepared on a Ni_(3)Al-base single crystal(SC)superalloy via electroplating and gaseous aluminizing treatments,wherein the electroplating procedures consisted of the composite deposition of Ni-Re followed by electroplating of Pt.In order to perform a comparison with conventional Ni Al and(Ni,Pt)Al coatings,the cyclic oxidation performance of the Ni Re Pt Al coating was evaluated at 1100 and 1150℃.We observed that the oxidation resistance of the Ni Re Pt Al coating was significantly improved by the greater presence of the residualβ-Ni Al phase in the outer layer and the lesser outward-diffusion of Mo from the substrate.In addition,the coating with the Re-rich diffusion barrier demonstrated a lower extent of interdiffusion into the substrate,where the thickness of the second reaction zone(SRZ)in the substrate alloy decreased by 25%.The mechanisms responsible for improving the oxidation resistance and decreasing the extent of SRZ formation are discussed,in which a particular attention is paid to the inhibition of the outward diffusion of Mo by the Re-based diffusion barrier.
文摘<div style="text-align:justify;"> The discovery of Earth’s radiation zone divided into two belts is the first major discovery in Human space exploration. The inner belt dominated by energetic protons and the outer belt dominated by energetic electrons imply the inner belt with net positive charge and the outer belt with net negative charge. Earth’s surface carries net negative charge. These exploration data suggest the inner and outer parts of a star may be composed of several discrete charged layers. We propose the mechanism of the star’s multiple Debye spherical layers to adapt to the objective existence. The charged particles in the near-earth space follow the statistical distribution of multiple Debye spherical layers of Earth. The inner belt and outer belt is the main body of layer 8 and layer 9 respectively. The empty slot between the inner and outer belt comes from the action of the electric field between them. An impenetrable barrier to ultra-relativistic electrons originates from the action of the electric field of layer 7. </div>
