Tunable antiferroelectric-like polarization behavior and enhanced energy storage characteristics in symmetric BaTiO_(3)/BiFeO_(3)/BaTiO_(3) heterostructure

The excellent energy storage performances of dielectric materials,a high energy density and efficiency,the stability in a wide range of temperature,frequency and cycling time,are surely desirable for the energy storage devices.A trade-off relationship between polarization and breakdown strength,however,limits the enhancement of energy storage properties of dielectric materials.To effectively boost the energy density and efficiency of dielectric capacitors,by inserting a BiFeO_(3) layer into the BaTiO_(3) film in present case,the symmetric BaTiO_(3)/BiFeO_(3)/BaTiO_(3) tri-layer film heterostructure with antiferroelectric-like characteristics was constructed based on the dual-interlayer coupling effect,what's more,its antiferroelectric-like characteristics will evolve with electric field.Such the tunable polarization behavior endows it with an enhanced maximum polarization but a reduced remnant one,a delayed saturation of polarization and a high breakdown strength,which are synergistically accountable for a large energy density(Wrec∼109 J/cm^(3))and a high efficiency(η∼82.6%),together with the good thermal(TR∼200℃,ΔWrec<3%&Δη<10%)and frequency(50 Hz–10 kHz,ΔWrec<7%&Δη<13%)stabilities,particularly an outstanding cycling reliability(10^(9) cycles,both ΔWrec and Δη<1%).Hence these findings can provide some innovative ideas for enriching the performance tuning of ferroelectrics,especially in enhancing their energy storage characteristics.

Pitting Corrosion Behavior of Stainless Steel 304 in Carbon Dioxide Environments

With a rotating cylinder electrode apparatus, the polarization behaviors of the mild steel and the stainless steel 0Cr18Ni9 in NaHCO 3 (0.5 M)+Na 2CO 3 (0.5 M) solution with and without erodent particles were investigated and compared. The results show that the rotation speed of cylinder hardly affects the polarization behavior of sample in solution without particles but exerts a great influence on that with particles. Increasing rotation speed, the free corrosion potential shifts to positive direction and the oxygen limiting current density increases. Both the mild steel and stainless steel 0Cr18Ni9 experience a significant increase of the mass loss by increasing erosion, and erosive wear was dominated by severe micro-plowing. The insufficient mechanical strength of both materials leads to a low resistance to particle removal. Increasing peripheral velocities of the rotating cylinder enhances the corrosion rate of the mild steel. The stainless steel 0Cr18Ni9, due to a high erosive wear, also suffers from similar erosion-corrosion damage, despite that its corrosion resistance is much higher than that of the mild steel.

Erosion and Corrosion of Mild Steel and Stainless Steel in Sodium Carbonate/Bicarbonate Solution Bearing Alumina Particle

With a rotating cylinder electrode apparatus,the polarization behaviors of the mild steel and the stainless steel 0Cr18Ni9 in NaHCO3(0.5M)+Na2CO3(0.5M)solution with and without erodent particles were investigated and compared.The results show that the rotation speed of cylinder hardly affects the polarization behavior of sample in solution without particles but exerts a great influence on that with particles.Increasing rotation speed,the free corrosion potential shifts to positive direction and the oxygen limiting current density increases.Both the mild steel and stainless steel 0Cr18Ni9 experience a significant increase of the mass loss by increasing erosion,and erosive wear was dominated by severe micro-plowing.The insufficient mechanical strength of both materials leads to a low resistance to particle removal.Increasing peripheral velocities of the rotating cylinder enhances the corrosion rate of the mild steel.The stainless steel 0Cr18Ni9,due to a high erosive wear,also suffers from similar erosion-corrosion damage,despite that its corrosion resistance is much higher than that of the mild steel.

Effect of solution pH,Cl- concentration and temperature on electrochemical behavior of PH13-8Mo steel in acidic environments

The effect of solution pH,Cl;concentration and temperature on the electrochemical corrosion behavior of PH13-8Mo steel in acidic solution was investigated by using the electrochemical tests,scanning electron microscopy and X-ray photoelectron spectroscopy.The PH13-8Mo martensitic precipitation hardened stainless steel is in the passivity state when the pH value is above 3.0,below which the anodic polarization curves of the steel are actively dissolved.The corrosion current density gradually decreases with increasing the solution pH and decreasing Cl;concentration and solution temperature.Pits are initiated on the sample surface in the presence of the Cl;and gradually developed into uniform corrosion with increasing the Cl;concentrations.Moreover,the corrosion is more serious with an increase in solution temperature.