The grain size of prior austenite has a distinct influence on the microstructure and final mechanical properties of steels. Thus, it is significant to clearly reveal the grain boundaries and therefore to precisely cha...The grain size of prior austenite has a distinct influence on the microstructure and final mechanical properties of steels. Thus, it is significant to clearly reveal the grain boundaries and therefore to precisely characterize the grain size of prior austenite. For NiCrMoV rotor steels quenched and tempered at high temperature, it is really difficult to display the grain boundaries of prior austenite clearly, which limits a further study on the correlation between the properties and the corresponding microstructure. In this paper, an effective etchant was put forward and further optimized. Experimental results indicated that this agent was effective to show the details of grain boundaries, which help analyze fatigue crack details along the propagation path. The optimized corrosion agent is successful to observe the microstructure characteristics and expected to help analyze the effect of microstructure for a further study on the mechanical properties of NiCrMoV rotor steels used in the field of nuclear power.展开更多
The solvent extraction of copper from simulated ammoniacal spent etchant with 1-（4＇-dodecyl）-phenyl-3-tertiary butyl-1,3-octadione（HR） was studied,and a model of extraction isotherm was proposed and verified with...The solvent extraction of copper from simulated ammoniacal spent etchant with 1-（4＇-dodecyl）-phenyl-3-tertiary butyl-1,3-octadione（HR） was studied,and a model of extraction isotherm was proposed and verified with equilibrium extraction constant.The influence of equilibration time,extractant concentration and phase ratio on the extraction of copper was studied at（298±0.5） K.For the spent etching solutions containing 112.98 g/L Cu,6 mol/L NH3 and 1 mol/L NH4＋,the optimal solvent extraction condition of copper was obtained in one-stage solvent extraction at phase ratio of 5：4 with 40% HR in sulphonated kerosene for 5 min.The copper concentration in the raffinate decreased to 63.24 g/L and raffinate can be favorably recycled to the etching solution.The stripping studies were carried out with the simulated copper spent electrolyte containing 30 g/L Cu and 180 g/L H2SO4.The stripping ratio is 98.27% from the loaded organic phase after one-stage stripping at phase ratio of 1：2 at（298±0.5） K.展开更多
A close-looped process based on the membrane separation and electrolysis is proposed to regenerate the copper etchant in-situ, recover copper on-site and reuse it. It is characterized by selective separation of copper...A close-looped process based on the membrane separation and electrolysis is proposed to regenerate the copper etchant in-situ, recover copper on-site and reuse it. It is characterized by selective separation of copper from the spent etchant, which is accomplished by the ion exchange membrane-electrowinning, and at the same time the other components useful for etching are reclaimed. The experiments show that at least 90 % of electricity efficiency for copper removal can be maintained and the optimum condition for membrane-electrowinning is: cell voltage 2 -2.5 V, operating temperature 40 - 50 ℃ and current density 500 - 1 500 A/m2. The regenerated etchant can be suc cessfully reused to etch copper after adjusting its composition to the normal range, and its recycling property is as good as that of the fresh etchant after 50 times of use-disposal-regeneration cycles.展开更多
In order to protect the finished structures on the front side during deep silicon wet etching processes, the wax coating for double-sided etching process on the wafer is studied to separate the aforementioned structur...In order to protect the finished structures on the front side during deep silicon wet etching processes, the wax coating for double-sided etching process on the wafer is studied to separate the aforementioned structures from the strong aqueous bases. By way of heating and vacuumization, the air bubbles are expelled from the coating to extend the protection duration. The air pressure in the sealed chamber is 0.026 7 Pa, and the temperature of the heated wafer is 300℃. Two kinds of the wax are used, and the corresponding photos of the etched wafer and the protection times are given. In 75 ℃ 10 % KOH solution, the protection duration is more than 8 h.展开更多
Electrochemical technologies for the on-site treatment of spent acid etchant have received great attention due their ease of operation and economic benefits. On the other hand, a large amount of Cl2 is generated durin...Electrochemical technologies for the on-site treatment of spent acid etchant have received great attention due their ease of operation and economic benefits. On the other hand, a large amount of Cl2 is generated during the electrolysis process, which leads to potential environmental risks. In the present work, a novel threecompartment ceramic membrane flow reactor, including a cathode chamber, an anode chamber, and a gas absorption chamber was developed. The three chambers were divided by an Al2O3 ceramic membrane and a breathable hydrophobic anode diffusion electrode(ADE). The Cl2 evolution onset potential of the ADE was increased to 1.19 V from 1.05 V of the graphite felt, effectively inhibiting the chlorine evolution reaction(CER).The anode-generated Cl2 diffused into the gas absorption chamber through the ADE and was eventually consumed by the H2O2 adsorbent. Cu could be recovered without emitting chlorine due to the special structure of reactor. The current efficiency of copper precipitation and cathode reduction from Cu2+to Cu+reached 97.7%at a working current of 150 m A. These results indicated that the novel membrane reactor had high potential for application in the copper recovery industry.展开更多
By introducing the mechanical motion into the confined etchant layer technique(CELT), we have developed a promising ultraprecision machining method, termed as electrochemical mechanical micromachining(ECMM), for produ...By introducing the mechanical motion into the confined etchant layer technique(CELT), we have developed a promising ultraprecision machining method, termed as electrochemical mechanical micromachining(ECMM), for producing both regular and irregular three dimensional(3 D) microstructures. It was found that there was a dramatic coupling effect between the confined etching process and the slow-rate mechanical motion because of the concentration distribution of electrogenerated etchant caused by the latter. In this article, the coupling effect was investigated systemically by comparing the etchant diffusion, etching depths and profiles in the non-confined and confined machining modes. A two-dimensional(2 D) numerical simulation model was proposed to analyze the diffusion variations during the ECMM process, which is well verified by the machining experiments. The results showed that, in the confined machining mode, both the machining resolution and the perpendicularity tolerance of side faces were improved effectively. Furthermore, the theoretical modeling and numerical simulations were proved valuable to optimize the technical parameters of the ECMM process.展开更多
WHEN scanning electrochemical microscopy (SECM) with feedback mode is used to etchcertain surface, the etchant molecules generated at a microelectrode diffuse to the surface andreact therein with the surface species, ...WHEN scanning electrochemical microscopy (SECM) with feedback mode is used to etchcertain surface, the etchant molecules generated at a microelectrode diffuse to the surface andreact therein with the surface species, resulting in local etching pattern. It is noted that theetching resolution of SECM is dominantly determined by the size of the microelectrode.However, many experimental results have shown the significant influence of the lateral diffu-sion of etchant on the etching resolution. Therefore, a thin diffusion layer of the展开更多
文摘The grain size of prior austenite has a distinct influence on the microstructure and final mechanical properties of steels. Thus, it is significant to clearly reveal the grain boundaries and therefore to precisely characterize the grain size of prior austenite. For NiCrMoV rotor steels quenched and tempered at high temperature, it is really difficult to display the grain boundaries of prior austenite clearly, which limits a further study on the correlation between the properties and the corresponding microstructure. In this paper, an effective etchant was put forward and further optimized. Experimental results indicated that this agent was effective to show the details of grain boundaries, which help analyze fatigue crack details along the propagation path. The optimized corrosion agent is successful to observe the microstructure characteristics and expected to help analyze the effect of microstructure for a further study on the mechanical properties of NiCrMoV rotor steels used in the field of nuclear power.
基金Project (2007CB613601) supported by the National Basic Research Program of China
文摘The solvent extraction of copper from simulated ammoniacal spent etchant with 1-（4＇-dodecyl）-phenyl-3-tertiary butyl-1,3-octadione（HR） was studied,and a model of extraction isotherm was proposed and verified with equilibrium extraction constant.The influence of equilibration time,extractant concentration and phase ratio on the extraction of copper was studied at（298±0.5） K.For the spent etching solutions containing 112.98 g/L Cu,6 mol/L NH3 and 1 mol/L NH4＋,the optimal solvent extraction condition of copper was obtained in one-stage solvent extraction at phase ratio of 5：4 with 40% HR in sulphonated kerosene for 5 min.The copper concentration in the raffinate decreased to 63.24 g/L and raffinate can be favorably recycled to the etching solution.The stripping studies were carried out with the simulated copper spent electrolyte containing 30 g/L Cu and 180 g/L H2SO4.The stripping ratio is 98.27% from the loaded organic phase after one-stage stripping at phase ratio of 1：2 at（298±0.5） K.
文摘A close-looped process based on the membrane separation and electrolysis is proposed to regenerate the copper etchant in-situ, recover copper on-site and reuse it. It is characterized by selective separation of copper from the spent etchant, which is accomplished by the ion exchange membrane-electrowinning, and at the same time the other components useful for etching are reclaimed. The experiments show that at least 90 % of electricity efficiency for copper removal can be maintained and the optimum condition for membrane-electrowinning is: cell voltage 2 -2.5 V, operating temperature 40 - 50 ℃ and current density 500 - 1 500 A/m2. The regenerated etchant can be suc cessfully reused to etch copper after adjusting its composition to the normal range, and its recycling property is as good as that of the fresh etchant after 50 times of use-disposal-regeneration cycles.
文摘In order to protect the finished structures on the front side during deep silicon wet etching processes, the wax coating for double-sided etching process on the wafer is studied to separate the aforementioned structures from the strong aqueous bases. By way of heating and vacuumization, the air bubbles are expelled from the coating to extend the protection duration. The air pressure in the sealed chamber is 0.026 7 Pa, and the temperature of the heated wafer is 300℃. Two kinds of the wax are used, and the corresponding photos of the etched wafer and the protection times are given. In 75 ℃ 10 % KOH solution, the protection duration is more than 8 h.
基金Supported by the National Natural Science Foundation of China(21838005,21676139)the Higher Education Natural Science Foundation of Jiangsu Province(15KJA530001)+1 种基金the Key Scientific Research and Development Projects of Jiangsu Province(BE201800901)Research Fund of State Key Laboratory of MaterialsOriented Chemical Engineering(ZK201604).
文摘Electrochemical technologies for the on-site treatment of spent acid etchant have received great attention due their ease of operation and economic benefits. On the other hand, a large amount of Cl2 is generated during the electrolysis process, which leads to potential environmental risks. In the present work, a novel threecompartment ceramic membrane flow reactor, including a cathode chamber, an anode chamber, and a gas absorption chamber was developed. The three chambers were divided by an Al2O3 ceramic membrane and a breathable hydrophobic anode diffusion electrode(ADE). The Cl2 evolution onset potential of the ADE was increased to 1.19 V from 1.05 V of the graphite felt, effectively inhibiting the chlorine evolution reaction(CER).The anode-generated Cl2 diffused into the gas absorption chamber through the ADE and was eventually consumed by the H2O2 adsorbent. Cu could be recovered without emitting chlorine due to the special structure of reactor. The current efficiency of copper precipitation and cathode reduction from Cu2+to Cu+reached 97.7%at a working current of 150 m A. These results indicated that the novel membrane reactor had high potential for application in the copper recovery industry.
基金supported by the National Natural Science Foundation of China (21573054, 21327002, 91323303, 21621091)the Joint Funds Key Project of the National Natural Science Foundation of China (U1537214)+2 种基金the State Key Program of National Natural Science of China (51535003)Self-Planned Task (SKLRS201606B) of State Key Laboratory of Robotics and System (HIT)the Open Project of the State Key Laboratory for Manufacturing Systems Engineering (Xi'an Jiaotong University)
文摘By introducing the mechanical motion into the confined etchant layer technique(CELT), we have developed a promising ultraprecision machining method, termed as electrochemical mechanical micromachining(ECMM), for producing both regular and irregular three dimensional(3 D) microstructures. It was found that there was a dramatic coupling effect between the confined etching process and the slow-rate mechanical motion because of the concentration distribution of electrogenerated etchant caused by the latter. In this article, the coupling effect was investigated systemically by comparing the etchant diffusion, etching depths and profiles in the non-confined and confined machining modes. A two-dimensional(2 D) numerical simulation model was proposed to analyze the diffusion variations during the ECMM process, which is well verified by the machining experiments. The results showed that, in the confined machining mode, both the machining resolution and the perpendicularity tolerance of side faces were improved effectively. Furthermore, the theoretical modeling and numerical simulations were proved valuable to optimize the technical parameters of the ECMM process.
文摘WHEN scanning electrochemical microscopy (SECM) with feedback mode is used to etchcertain surface, the etchant molecules generated at a microelectrode diffuse to the surface andreact therein with the surface species, resulting in local etching pattern. It is noted that theetching resolution of SECM is dominantly determined by the size of the microelectrode.However, many experimental results have shown the significant influence of the lateral diffu-sion of etchant on the etching resolution. Therefore, a thin diffusion layer of the
