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Micro electroforming has become one of the key technologies for metal micro devices fabrication. However, residual stress in electroformed layer of micro devices will reduce their dimensional accuracy and service life. Affected by residual stresse, there is serious bending deformation occurred in cantilevered micro structure during electroforming process. In this paper, megasonic agitation method was employed to obtain low stress in the cantilevered micro structure firstly. Then, the cantilevered micro structures electroformed with and without megasonic were tested by nanoindentation method. The difference of Suresh model and Lee model on the stress calculation results was discussed. By contrast with X-ray diffraction (XRD) method, the calculation results obtained by Lee model in nanoindentation testing are closer to the actual residual stress of the nickel electroformed layer. The nanoindentation testing results obtained by Lee model show that the mean compressive stress of micro structures electroformed with megasonic has a decrease of 57.84 % compared with that without megasonic. The research results indicated that megasonic agitation method is a low residual stress fabrication technique in micro electroforming process. Besides, nanoindentation is a feasible method to measure the residual stress of metal micro structure, due to its excellent properties of high spatial resolution and wide application range.

Three-dimensional carbon-based porous materials have proven to be quite useful for tailoring material properties in the energy conservation and environmental protection applications. In view of the three-dimensional and well-defined structure of metal-organic frameworks (MOFs), a novel carbon-based magnetic porous material (HKUST-Fe3O4) has been designed and constructed by MOF-guest interactions of high-temperature pyrolysis. The obtained HKUST-Fe3O4 exhibited the unique features of superparamagnetism, a macro/mesoporous structure, environmental protection (inexistence of toxic heavy metal ions), and physicochemical stability and has shown high adsorption capacity and rapid adsorption for carcinogenic organic pollutants (for example, rhodamine B) with an environmentally friendly character and excellent reusability. We demonstrate that the unique/superior advantages of HKUST-Fe3O4 could meet the requirements of environment cleaning, especially for removing the targeted organic pollutant from water. Moreover, the specific HKUST-Fe3O4 and organic pollutant interaction mechanism has been analyzed in detail via parameter-free calculations. This study proposes a promising strategy for constructing novel carbon-based magnetic nanomaterials for various applications, not limitated to pollutant removal.

Three-dimensional porous carbon-based materials from metal–organic frameworks (MOFs) have been proven useful in structural mechanical and catalytic applications due to the high specific surface area and excellent electron transport property. However, introducing and loading of metal catalytic sites on MOF-derived porous carbon-based materials always involves complex multistep synthetic processes and unwarrantable catalyst sites with high catalytic activity. Here, we have developed a facile Mo-doping-assisted strategy to construct a highly active nanorod with Ni-based catalyst nanoparticles from a MOF (MCF-61). Thanks to the assistance of Mo-doping to restrain the migration and aggregation of elemental Ni, the obtained Mo-doped Ni-based catalyst (MNC) exhibited excellent catalytic activity in the solution-phase hydrogenation of nitrophenols compared to those reported in other studies. Moreover, the role of molecular structures of nitrophenols on their reduction in MNC has been revealed by quantum chemical ...

Through-mask electrochemical etching (TMEE) is one of the main methods to fabricate metal microstructures array in large scale. In deep metal microstructure etching process, lateral corrosion problem seriously affects the etching localization. In this paper, megasonic and particle combined through mask electrochemical etching (MP-TMEE) method was proposed to improve the etching localization in TMEE process. Experimental results show that the etching factor (EF) was greatly improved by MP-TMEE method compared to traditional TMEE. With the use of MP-TMEE, when the feature size of the mask was 100 μm, the average diameter and depth of the etched micro pits were 148.7 μm and 59.9 μm. The use of MP-TMEE instead of TMEE leads to an increase in EF from 1.58 to 2.50. Besides, the mechanism of the synergistic effect of megasonic and the particles in MP-TMEE process was investigated. An erosion theoretical model of passivation film was established and verified by electrochemical impedance spectroscopy (EIS) method. The measurement results of EIS show that the micro pit depth and the passivation film resistance have the opposite variation trend, and the passivation film resistance measurement results are consistent with the trend of the theoretical model. Finally, microstructure arrays involving stainless steel micro pit array and micro pillar array, copper micro pit array and micro pillar array were fabricated using MP-TMEE method.

Computer simulation accelerates the selection and application of new electrode materials. The First-principles calculations based on density functional theory (DFT) are performed to evaluate the performance as cathode for Potassium ion batteries (PIBs) on the structure, electronic conductivity and ionic diffusion of O-doped KMnF3. After taking comprehensive consideration of the calculation results, the nanostructured O-doped KMnF3 was synthesized and the structure and electrochemical properties were further improved by carbon coating. Here, we report a new etch pathway to create a new class of carbon-coated perovskite fluoride to improve the performance of PIB in terms of rate capability and cycle stability. These new material design concepts will help discover and synthesize new materials for PIBs.

Based on lithography and electrochemical deposition technology, an integrative fabrication method of micro RF coaxial transmitter on copper substrates combining positive and negative photoresist processes is proposed in this paper. In this method, positive photoresist (AZ50XT) was used for fabricating sacrificial layer which worked as master mold for electroforming copper; negative photoresist (SU-8) was used for fabricating insulating layer. However, due to the distribution of light intensity inside the AZ50XT photoresist is uneven during the lithography process, which will cause the sidewall of the film tilted. Thus, a method of multiple exposures and developments was proposed to improve the sidewall inclination of the AZ50XT photoresist and provide an accurate master mold for electrochemical deposition of the structure. Meanwhile, contrast experiments were conducted to verify the practical effect. The experiments results show that when the thickness of AZ50XT film is 65 μm, the sidewall inclination can be increased from 67.4° to 84.5°. In addition, the soft-bake parameter was adjusted to further improve the sidewall inclination of AZ50XT film. Ultimately, based on the experimental results, a micro RF coaxial transmitter was fabricated. The outline size of the coaxial transmitter is 3000 μm × 400 μm × 200 μm.

Through-mask electrochemical micromachining (TMEMM) is the primary method to fabricate micro pits with controlled size, location, and density. In order to improve the machining localization and deep etching capability in TMEMM process, a novel method which combined megasonic vibration to TMEMM process is presented in this paper. Firstly, the coupling relationship between sound field, gas-liquid two-phase flow field and electrolytic process was theoretically analyzed. Theoretical analysis results indicate that acoustic wave agitation can promote the electrolytic process by increasing the conductivity of the electrolyte. Based on this theory, a numerical simulation method was used to predict anodic profiles under different megasonic intensity. The simulation results show that the addition of megasonic agitation can obviously improve the machining localization and deep etching capability in TMEMM process. Etching depth of the micro pit increased from 48.22 μm to 77.98 μm with megasonic agitation compared to the without megasonic one. Depth-diameter ratio of the micro pit increased from 0.30 to 0.45. Meanwhile, the etching factor (EF) increased from 1.55 to 2.10. Then, a megasonic electrolyser at 1 MHz was set up, micro pits were etched under different megasionc intensity. The experiment results show that megasonic assisted through-mask electrochemical micromachining (MA-TMEMM) had best process performance when it worked with the increase of megasionc intensity. When the megasonic intensity was 8 W/cm2, micro pits with average diameter of 167.77 μm and 79.62 μm in depth were successfully fabricated. The average depth-diameter ratio of the micro pits was as high as 0.47, and the EF was as high as 2.35. The working mechanism of megasonic in MA-TMEMM process was analyzed too.