Ceramic Rings Research Articles

Transverse broadband impedance reduction techniques in a heavy ion accelerator

The transverse broadband impedances of major components in the BRing (booster ring) of HIAF (High Intensity Heavy-ion Accelerator Facility) are estimated using the analytical formulas or the wakefield solver in the CST Studio Suite. At low frequency, the transverse broadband impedance model of BRing is ${Z}_{1}^{H}(\ensuremath{\omega})=\ensuremath{-}417.14i\text{ }\text{ }\mathrm{k}\mathrm{\ensuremath{\Omega}}/\mathrm{m}(\mathrm{horizontal})$ and ${Z}_{1}^{V}(\ensuremath{\omega})=\ensuremath{-}530.19i\text{ }\mathrm{k}\mathrm{\ensuremath{\Omega}}/\mathrm{m}(\mathrm{vertical})$, which are larger than the threshold impedance for the transverse mode-coupling instability. The ceramic rings in the vacuum chamber are the primary source of impedance. With a goal of mitigating the instability by reducing the impedance of ceramic rings, a high conductivity coating is discussed in detail. In addition, a prototype of ceramic rings-loaded thin-wall vacuum chamber is manufactured and the impedance measurements are performed. When ceramic rings are coated by $2\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$-copper, the CST simulation and experiment results show that the transverse broadband impedance of ceramic rings-loaded thin-wall vacuum chamber can be reduced from ${Z}_{1}^{H}(\ensuremath{\omega})=\ensuremath{-}291.69i\text{ }\mathrm{k}\mathrm{\ensuremath{\Omega}}/\mathrm{m}$ and ${Z}_{1}^{V}(\ensuremath{\omega})=\ensuremath{-}352.37i\text{ }\mathrm{k}\mathrm{\ensuremath{\Omega}}/\mathrm{m}$ to ${Z}_{1}^{H}(\ensuremath{\omega})=\ensuremath{-}46.16i\text{ }\mathrm{k}\mathrm{\ensuremath{\Omega}}/\mathrm{m}$ and ${Z}_{1}^{V}(\ensuremath{\omega})=\ensuremath{-}64.56i\text{ }\text{ }\mathrm{k}\mathrm{\ensuremath{\Omega}}/\mathrm{m}$. Furthermore, in this case the transverse broadband impedance model of BRing is reduced by more than 50% to ${Z}_{1}^{H}(\ensuremath{\omega})=\ensuremath{-}171.61i\text{ }\text{ }\mathrm{k}\mathrm{\ensuremath{\Omega}}/\mathrm{m}$ and ${Z}_{1}^{V}(\ensuremath{\omega})=\ensuremath{-}242.38i\text{ }\text{ }\mathrm{k}\mathrm{\ensuremath{\Omega}}/\mathrm{m}$.

Quality improvement of syngas from gasification process of palm kernel using NiO/CaO catalysts on ceramic supporter in coupled with biochar absorbent from agricultural residues

In this study, palm kernel shells were utilized in the gasification process to produce syngas. In addition, biochar prepared from pyrolysis of the left-over mangosteen and durian peels were used in the gasification process to enhance the tar removal efficiency. The expected outcomes of this study could result in not only the generation of renewable energy from but also the waste utilization of agricultural residues. The effect of catalysts and biochar on the syngas quality improvement were particularly studied. Palm kernel shell was used as raw material. The compositions and heating values of the biomass were characterized by the proximate, ultimate, and bomb analyses, respectively. Syngas was produced from a downdraft gasifier connected with catalytic and adsorption units in sequence. The gasification process was operated with 1 kg of palm shell per batch at a fixed air flow rate of 25 L/min. The NiO/CaO (10 %wt) catalysts on ceramic supporter with various NiO contents of 2%, 4%, and 8% were synthesized by co-impregnation. Biochars were synthesized by pyrolysis process of durian and mangosteen peels at around 300 - 500 °C for 2 hrs. Morphology and compositions of the synthesized catalysts and biochar were analyzed. The results of SEM analysis showed that the NiO and CaO were deposited and well dispersed on the porous ceramic ring supporters. The presence of active NiO on the catalyst was also confirmed in FTIR result with (wavelength of 692 cm−1). Biochar from durian and mangosteen peels, with BET surface area of 0.9219 - 0.9989 m2/g and adsorption pore size of 11.193 - 11.912 nm, were obtained from a pyrolysis process at 400 - 700 °C. The syngas samples were collected from the gasification unit every 15 min to 60 min. The gas chromatography was used to analyze the syngas compositions. The GC results indicated that increasing NiO contents in the catalysts tended to result in increasing CH4 composition of the syngas for both systems with and without biochar. With tar filtration unit containing biochar, the ability of tar removal was significantly increased by 2 to 9 times comparing to the system without biochar.

Effects of Simulation‐Guided Microwave Presintering Process on the Preparation and Final Properties of Pure Ceramic Rings: Lower Sintering Temperature and Higher Mechanical Properties

In order to improve the performance and endurance of steel rings used for twisting and winding yarns in the textile industry, a more wear‐resistant ceramic version is studied and examined by conducting multiple simulations combined with microwave sintering experiments of the ring preparation process, aiming to reduce manufacturing costs and improve efficiency. The three‐dimensional (3D) electromagnetic field simulation software HFSS is used to simulate the electromagnetic field distribution in the microwave sintering cavity and to determine the electromagnetic region with the most uniform electromagnetic field to guide the microwave sintering experiments. The 3Y‐TZP ceramic rings are shaped by gel‐casting. The effect of presintering on the performance of ceramic rings is investigated by applying conventional sintering and microwave sintering methods. The experimental results show that the simulation‐guided microwave sintering process can resolve the deficiency of uneven microwave sintering at low temperatures. Comparing the final sintering temperatures and mechanical properties of the final ceramic‐sintered rings obtained by microwave presintering to those obtained by conventional presintering, microwave presintered sample has a final temperature of 1400°C, which is 100°C lower than that of conventional presintering, which is 1500°C; its average grain size of 0.18 μm is dramatically smaller than that of conventional presintering, which is 0.24 μm, with about 80% of the grain sizes present in the range of 0.1‐0.2 μm and a relative density of about 99%, as opposed to conventional presintering’s 70% falling between 0.2 and 0.3 μm and relative density of about 98%; the Vickers hardness and fracture toughness for microwave presintered sample reach 1550 kg·f·mm−2 and 9.05 MPa m1/2, respectively, which are both greater than 1431 kg·f·mm−2 and 8.86 MPa m1/2 in the conventional samples.

Improving the efficiency of a hollow ultrasonic motor by optimizing the stator’s effective electromechanical coupling coefficient

For application in control moment gyros, we considered a hollow traveling wave ultrasonic motor with a diameter of 70 mm. The effective electromechanical coupling coefficient (EMCC) of the stator was determined. The influence of the vibration mode of the stator and the structural dimensions of the metal elastomer and piezoelectric ceramic ring on the effective EMCC was investigated. According to the FEM simulation results, four different stators were manufactured and tested. The EMCC obtained through the simulations was greater than the measured values, with the lowest simulated and measured values being 17.202% and 16.431%, respectively, and the highest simulated and measured values being 28.452% and 26.780%, respectively. The relative errors between the simulated and measured values were all less than 10%. This work will help us to improve the output efficiency of the motor.

PURIFICATION OF WATER FROM PHENOL BY BACTERIA OF THE GENUS PSEUDOMONAS IMMOBILIZED ON NATURAL AND SYNTHETIC CARRIERS

Aim. Optimization of the process of water purification from phenol using bacteria of the genus Pseudomonas (P. cepacia ONU327, P. fluorescens ONU328, P. maltophilia ONU329) immobilized on natural and synthetic carriers. Methods. The concentration of phenol in water was determined by extraction-photometric method using 4-aminoantipyrin. For purification of water from phenol (with a concentration of 200 mg / l) non-pathogenic individual strains of bacteria P. fluorescens ONU328, P. maltophilia ОNU329, P. cepacia ОNU327, immobilized on carriers of different nature (zeolite, mussel doors, river sand, ceramic rings, activated carbon, high peat, synthetic carrier type "VIYA"). Results. There were experimentally confirmed that adhesion of cells of the bacterial strains of P. cepacia ONU327, P. fluorescens ONU328, P. maltophilia ONU329 to zeolite, river sand (which practically do not sorb phenol) contributed to the effective biodegradation of phenol by 96–100% (depending on the selected strain bacteria). The residual concentration of phenol in water during its treatment (for 11 days) by cells of P. fluorescens ONU328 strain or P. maltophilia ONU329 strain immobilized on zeolite decreased from 200 mg / l to 8.0±0.95 mg / l (water purification from phenol (α) – 96%) and up to 2.0±0.14 mg / l (α = 99%) – when using immobilized cells of the strain P. cepacia ONU327. It was established that when river microorganisms-destructors were immobilized on the river sand, the residual concentration of phenol in water on the 11th day of treatment was 6.0 ± 0.55 mg / l (α = 97%) and 2.0±0.14 mg / l (α = 99%) – respectively for the strains of P. maltophilia ONU329 and P. fluorescens ONU328; and reached the level of maximum permissible concentration (MPC = 0.001 mg / l) – in the case of river cells of strain P. cepacia ONU327 immobilized in the sand of the river. It was established experimentally that the acceleration of water purification from phenol occurred when using cells of bacteria of the genus Pseudomonas (P. cepacia ОNU327, P. fluorescens ONU328) immobilized on ceramic tubes and a fibrous nozzle of the “VIYA” type. Within 5 days of exposure, the degree of water purification from phenol immobilized on the fibrous attachment of the VIYA type by destructive microorganisms, taking into account the control correction (native unmodified sorbent of the VIA type) reached 97% – as a result of the action of the strain P. cepacia ONU327; and 99% – as a result of the strain P. fluorescens ONU328. Conclusion. To accelerate the purification of water from phenol (for 5 days) by 97–99%, it is recommended to use the strains of the bacteria P. cepacia ONU327 and P. fluorescens ONU328 immobilized on a fibrous nozzle of the type "VIYA". Full dephenolization of water is observed when it is treated with the strains of bacteria P. cepacia ONU327, P. fluorescens ONU328, which are immobilized separately on activated carbon, river sand (for the strain P. cepacia ONU327) and on the mussel doors (for the strain P. fluorescens ONU328), respectively.

Effect of surface modification of ferroelectric ceramic component on the properties of PZT-type/epoxy piezoelectric composite with spiral structure

A PZT-type ceramic/epoxy resin piezoelectric composite with spiral structure was fabricated by a roll forming-curling method. The ceramic component surface was modified by silane coupling agent KH560 or titanate coupling agent NDZ201 before the spiral ceramic ring was compounded with epoxy matrix. Interface defects are reduced after some time of surface modification. The effects of the two coupling agents on the properties of composites were discussed and compared. The d33 and the hydrostatic figure of merit (FOM) of the composites with KH560 are 7.5% and 29.5% higher than those prepared without the coupling agent. However, the d33 and FOM of the composites treated by NDZ201 are lower than those prepared without the coupling agent. The different structures of the molecular layer at the interface of silane coupling agents and titanate coupling agents play a key role in the different effects on the properties.

Electrode shape dependence of the barbell-shaped magneto-mechano-electric energy harvester for low-frequency applications

A magneto-mechano-electric (MME) device for energy harvesting from ambient low-frequency magnetic field is investigated in this study. Consisting of piezoelectric ceramic rings, NdFeB permanent magnets and union piece, the proposed MME energy harvester is designed with the barbell-shaped structure operating in d33 mode. NdFeB permanent magnets are attached at the free end of barbell-shaped structure, which can produce compressive stress on the piezoelectric ceramic rings via magnetic torque effect. The properties of the MME energy harvester are optimized by using the finite element analysis. Two electrode shapes, including full electrode and divided electrode, are investigated in the aspect of their influences on the device performance. The finite element analysis is consistent with the experimental results, revealing that the electrode shape of piezoelectric ceramic rings is crucial for the performance of the proposed MME device. The MME device presents a low resonant frequency (<50 Hz), a magnetoelectric coefficient higher than 1 V/cm Oe, a high output voltage (>10 V @ 10 Oe), a maximum output power of ˜10.5 μW and a maximum power density of 3.5 μW/Oe cm3, demonstrating the potential applications for harvesting ambient low-frequency magnetic field energy.

High-repetition rate, single-frequency laser with a double Er:YAG ceramics ring cavity.

A high pulse repetition frequency (PRF) single-frequency Er:YAG ceramic ring laser is demonstrated. A double-ceramics ring cavity both end-pumped by a 1532-nm fiber laser is also used to increase the pulse energy. The maximum single-frequency output energies are 21.0 mJ, 18.3 mJ, and 14.4 mJ at the PRF of 500 Hz, 750 Hz, and 1 kHz, respectively. Correspondingly, the pulse widths are 93.2 ns, 106.8 ns, and 130 ns. To the best of our knowledge, this is the highest energy at high PRFs obtained from a single-frequency injection-seeded Er:YAG ceramic laser.

Application of solar photocatalytic ozonation in water treatment using supported TiO2

TiO2 P25 supported on mullite ceramic foams (CF) and glass raschig rings (GR), have been prepared by dip-coating with calcination at 500 °C. The (photo) catalytic activity of these materials in the degradation of N, N-diethyl-m-toluamide (DEET) by different AOPs, in ultrapure water or in a secondary effluent, has been tested. Under the conditions applied, for a given process, the performance of CF and GR supported catalysts was similar, and a slight improvement was observed only from 1 to 2 TiO2 coatings, indicating that, regardless of the support, after the second coating the amount of TiO2 (2.4 and 0.49 wt% for CF and GR, respectively), was in excess with respect to the solar UV photon flux and/or the ozone entering the reactor. Ozonation was the most effective process for DEET and A254nm removal, whereas solar photocatalytic ozonation led to the highest carboxylates formation and mineralization rates. At pH < 8.5, the presence of 5 mg L−1 PO43- or 20 mg L−1 IC as HCO3-/CO3= had no effect on DOC removal by this system, but some HO· scavenging effect was noticed when 40 mg L−1 IC was present, more markedly at pH > 8.5. The impact of the water matrix (ultrapure water, DOC0 15 mg L−1; or a secondary effluent, DOC0 11 mg L−1 and IC0 20 mg L−1), on the effectiveness of photocatalytic oxidation was high, and low for photocatalytic ozonation (45–50% DOC removed from both matrices after 2 h). After several cycles of use, almost no loss of activity of the supported materials was observed. By comparing the characterization results of fresh/used materials their stability is deduced.

Failure Analysis on a Compaction Roll made of Silicon Nitride

Abstract Owing to its excellent mechanical and thermal properties such as high strength, high hardness, and good thermal shock resistance, silicon nitride is a material suitable for forming tools. This work analyses the failure of a compaction roll made of Si3N4. One of the two ceramic rings broke during the compaction rolls' operation. Fractographic examinations have shown that very high tensile stresses occurred in the ceramic material during operation. These stresses first led to the formation of cracks and then to the total failure of the roll ring. Failure analysis has shown that roll design and clamping are of major importance. Causes for the generation of tensile stresses are shown and suggestions are made on how to ensure a safe operation of the rolls.

Design and Experiment of a High Average Power Ku-Band TE01 Mode Gyro-TWT

A high power Ku -band TE01 mode gyrotron traveling wave tube amplifier (gyro-TWT) is designed and experimented in this paper. The emphasis is put on the gyro-TWT with a high average power. In the design process, a low average velocity spread magnetron injection electron gun and a wideband multichannel TE01 mode input coupler are adopted. At the same time, a high average power curved collector is also applied. To suppress the potential gyro-backward wave oscillator interactions, a new type lossy ceramic rings and lossy ceramic pieces hybrid loaded structure is used in the high-frequency interaction circuit of gyro-TWT. In hot test, the developed Ku -band TE01 mode gyro-TWT is driven by a 70-kV 23-A helical electron beam and produce a ~31.5 kW maximum saturated output average power at 16.2 GHz, corresponding to a saturated peak power of ~450 kW (7% duty ratio), a saturated gain of ~40.5 dB, an efficiency of ~28%. The measured 3-dB bandwidth is ~2.1 GHz. The gyro-TWT is found to be zero-drive stable at these operating points.

Effect of Thermal‐Related Fit Clearance between Outer Ring and Pedestal on the Vibration of Full Ceramic Ball Bearing

Full ceramic bearing can work under a wide range of temperatures, but the thermal deformation difference between the ceramic outer ring and steel pedestal has a great increase with the rise of temperature and leads to obvious impact and friction. In this paper, the thermal deformation difference is considered and the fit clearance is taken as the boundary condition of the dynamic model. Investigations on the dynamic response of the outer ring are conducted, and the effect of thermal‐related fit clearance is analyzed at different working temperatures and rotation speeds through parametric study and experiments. Results show that the vibration of the outer ring grows with the temperature and shows different changes with rotation speed as the temperature changes. The variation of working temperature brings difference in the interactions between the outer ring and the pedestal, and the trends of vibration with rotation speed also change at different temperatures. Impact and friction make great contributions to the interactions between the outer ring and the pedestal and show different changes with temperature. This study puts forward a method for the calculation of bearing vibration at variable temperatures and provides theoretical basis for the application of the full ceramic bearings.

Circular Corrugated Miter Bend and Gap Losses for Broadband Frequency Applications

Circular corrugated waveguides are often used in fusion applications at single, multiple, or broadband millimeter frequencies due to their low ohmic loss, expected large frequency bandwidth, and direct coupling to free-space Gaussian modes. For single-frequency corrugated waveguide systems, transmission line components can be optimized to the desired frequency. For broadband or multiple-frequency applications, this is not possible. The goal of this paper is to demonstrate that the frequency bandwidth of circular corrugated waveguides can be compromised by diffraction losses to miter bends and gaps. It is shown that if the corrugation depth differs significantly from $\lambda $ /4, a theory can substantially underpredict the gap and miter bend losses. The simulations are also shown to compare favorably to experimental measurements. To improve the transmission line performance in large frequency bandwidth systems, such as 33–165 GHz reflectometry, reducing the number of miter bends may, therefore, be necessary. For the improvement of performance in narrower frequency bandwidth or multiple-frequency systems, especially high-powered systems, wavelength-dependent techniques may be applicable. One such application is shown for a Bragg reflection technique to reduce the thermal load to insulating ceramic rings in a dc break component for multiple-frequency ITER electron cyclotron heating transmission lines.

Trickling filter technology for biotreatment of nitrogenous compounds emitted in exhaust gases from fishmeal plants

Odour emissions are a major environmental issue associated with fishmeal production. Laboratory-scale biotrickling filters (BTFs) were inoculated with microbial consortia derived from sewage sludge, with the goal to study the biotreatment of low-loads of methylamines and ammonia that are main components of odorous exhaust gases produced by fishmeal processing plants. A BTF packed with ceramic rings was subjected to a real fishmeal plant emission containing trimethylamine (TMA), dimethylamine (DMA) and monomethylamine (MMA). The highest elimination capacities (ECs) obtained were 372 mg TMA m−3 h−1, 5.518 mg DMA m−3 h−1 and 1.038 mg MMA m−3 h−1, with maximal removal efficiencies of 92% (TMA), 83% (DMA) and 95% (MMA) after 30 days operation. In a different experiment, a polyurethane foam packing was employed to treat ammonia (NH3) at low inlet loads, reaching an EC of 47.19 mg N m−3 h−1 with 99.8% efficiency (inlet load of 47.27 mg N m−3 h−1). Likewise, the microbial community of the polyurethane-associated biofilm was diverse and stable during operation. These results suggested that elimination of volatile amino-compounds using BTFs inoculated with a methylotrophic microbial consortium holds potential for odour removal. In addition, sequencing analysis of 16S rDNA gene fragments allowed the identification of heterotrophic ammonia-oxidizing bacteria that are promising candidates to effectively maintain ammonia elimination in a biotreatment operation of nitrogenous compounds present in exhaust gases from fishmeal facilities.

16 W single-frequency laser output from an Er:YAG ceramic nonplanar ring oscillator

A high-power 1645 nm monolithic Er:YAG ceramic nonplanar ring oscillator (NPRO) is demonstrated. The maximum 1645 nm single-frequency power is 16.10 W, with a slope efficiency of 56.24% and an optical efficiency of 50.15%. The relative power stability of the Er:YAG ceramic NPRO laser is measured to be 0.33% in 30 min. When the temperature of the Er:YAG ceramic changed, the widest continuous tuning range without mode-hoping is 4.21 GHz. The line width of the Er:YAG ceramic NPRO laser is 4.4 kHz. The M2 factors are 1.20 and 1.27 in x and y directions, respectively.

The cure performance of modified ZrO2 coated by paraffin via projection based stereolithography

Projection based stereolithography (pSL) is widely applied to fabricate complicated ceramic parts. The preparation of ceramic suspension is critical for the process, especially, since large refractive index difference between ceramic and photosensitive resin would lead to an intense light scattering. In this paper, a ball-milling method is used to coat ZrO2 with paraffin that has a similar refractive index to that of resin, and the coated layer is measured to be around 10 nm. The modified ZrO2 is characterized by IR and TEM, and the photocuring behaviors are also investigated in terms of cure depth and excess cure width. The cure depth of modified ZrO2 increases by13.2% and 16.8% compared to the one without coating. At the same time, the excess cure width decreases by 77.1% and 62.7% using the same projection time. Moreover, ceramic ring prepared with the modified ZrO2 has a shrinkage of about 27.2%, and a density of 91.8%, smaller than the one prepared with ZrO2 without coating due to a burnout of paraffin. In conclusion, the paraffin coating layer could reduce the light scattering and thus improve the curing performance of ZrO2 suspension，especially, the excess cure width.

Using diffractive optical elements for industrial products geometrical parameters inspection

The paper describes industrial products geometrical parameters inspection systems. The systems are developed from a structured illumination method. An illuminating structure is formed by diffractive optical elements. Inspected objects of the system are smooth-bore weapon, fuel pellets, fuel rods, spacer grids, ceramic ring insulators. Diffractive optical elements used in the performance are focusators into rings or segments of a straight line. A focusator into arc is made for cylinder objects inspection. In this case, a focal plane aligns with a plane of the cylinder generatrix.

Study on the broadband piezoelectric ceramic transducer based on radial enhanced composite structure

A new type of broadband piezoelectric ceramic transducer is developed and analyzed. The transducer is composed of two radial enhanced composite vibrators with different resonance frequencies stacked along the axial direction. Each vibrator consists of a piezoelectric ceramic stack polarized in the thickness direction and a metal tube, and they are connected and excited to vibrate in the radial direction. On the basis of the radial vibrations of the piezoelectric ceramic thin ring and the metal tube, the electromechanical equivalent circuit of the transducer is derived and the input impedance of the transducer is obtained. The relationship between the resonance frequency and the geometrical dimensions of the transducer is analyzed. The new type of transducer is simulated using the ANSYS software. The simulated resonance frequencies of the transducer are in good agreement with the theoretical results. The transducer exhibits broadband characteristics because of the double stacking of vibrators with different resonance frequencies, and the transducer can be driven under high power because of its radial enhanced composite structure.

Performance Improvement of Zebra Batteries By Using a Simple and Functional Planar Architecture

ZEBRA batteries (Zero Emission Battery Research Activities) for their high energy and power density are one of the possible solutions to electrical storage for stationary applications. These systems are based on nickel chloride-sodium cells operating at high temperatures (about 270°–350 °C), and rely on a ceramic β”-alumina tube or planar membrane as solid electrolyte. In this work, recent results generated from 3 cm2 button cells, including base line cell performance, cell design and chemistry will be presented. The activity was directed to the realization of two new planar configuration of a beta sodium battery, that means the study of a planar sealing between the metal and the ceramic components. This battery, as many other electrochemical storage technologies, may play an important role for the transmission and distribution of electricity, because it can satisfy, in a very flexible way, many different needs (voltage and frequency control, self consumption of stochastic renewable energy, peak shaving etc.). For this purpose the storage system has to be characterized not only by a suitable energy capacity, but by quick response and high power performance too. A planar configuration could optimize the battery in terms not only of energy density (already satisfactory for this kind of batteries), but also of power density (still to be improved). The planar configuration could also provide a better stack design and thermal regulation. This battery utilizes a ceramic material as the ionic membrane between the anodic and cathodic semi cells and so it has to operate at 300°C. The current form of the β”-alumina membrane is “glass shaped” in order to contain the reagents, so the possible planar shape has to include a sealing system able to contain the reagents, which are in liquid status at the high temperature of the battery and they are also highly chemical reactive, especially the liquid sodium. In particular the research activity was previously directed to the study of the components of the seal between the metal bodies of the semi cells and the ceramic beta alumina and afterwards to a new configuration of the sealing system. The studied materials were insulating paints, ceramic pastes and glass seals and they were tested in order to assess their chemical stability in presence of sodium and their mechanical stability during thermal cycling. The research activity was addressed to define the right geometry of the ceramic support of the β”-alumina. Another purpose was to define a mechanical seals between the ceramics support and metallic body of the two, anodic and cathodic, electrodic compartments. A new activity was started to realize a new configuration in which also the body of battery was realized in ceramic material (α-Alumina), which allows a greater wettability in the anodic compartment. The mono cell was realized with a new sealing system, composed by a new geometry of a ceramic ring to contain the beta alumina membrane and to guarantee the mechanical stability. In both planar configurations of the cell made, it has been noticed that this type of design reduces the volume of the cathodic and anodic semi cell; in this way, not only the energy density is increased but also the power density is improved. Furthermore, the planar design would improve the stack geometry and its thermal distribution. The problems faced in this work were the material resistance to the chemical attack of liquid sodium at high temperature, the mechanical resistance and the compensation of the different thermal expansion coefficient between the solid electrolyte (β-alumina) and the metallic body. The first button cell consisted of two battery cases (stainless steel) for cathode and anode sides, a Nichel network cathode current collector, a stainless steel anode current collector, an α-alumina (99.5% purity) fixture and a planar composite yttria-stabilized zirconia (YSZ)/ BASE (3 cm2 active area) disc. The second buttom cell consisted of battery cases (α-Alumina) for cathode and anode sides, a steel plate held by a spring as a current collector both at the anode and at the cathode (the use of springs makes it possible to better exploit cathodic and anodic active materials), an α-alumina (99.5% purity) fixture and a planar composite yttria-stabilized zirconia (YSZ)/ BASE (3 cm2 active area) disc. It is using an inexpensive stacked design to improve performance at lower temperatures, leading to a less expensive overall storage technology. The new design greatly simplifies the manufacturing process, providing a subsequent pathway to the production of scalable, modular batteries at half the cost of the existing tubular designs.

Study on Precision Polishing of Alumina Ceramics

The research is mainly to investigate the surface roughness by the mechanical polishing for the processing of alumina ceramic materials. In the experiment, the ceramic test piece was placed between the ceramic work ring and the grinding disc and then grinded firstly with an alumina grinding slurry with a particle size of 10 μm to make the original roughness of the test piece reach Ra value of 1.49 μm. Then the silicon carbide slurry polishing was employed to conduct the experiments by changing the concentration of the polishing, particle size, load, rotation and time to observe the polishing effect of ceramic materials under different parameters. The results showed that the silicon carbide particle size of 2μm, with the polishing time of 50 min, the disc speed of 90 rpm, the concentration of 35%, the original surface roughness of alumina ceramic Ra 1.49μm could be downed to 0.22 μm. The improvement rate could reach 94%. And the greater the specimen load with the better grinding efficiency, the smaller the load caused worse cutting force between alumina and the specimen surface. However, the better the surface roughness when the time kept going. Furthermore, alumina ceramic test piece after precision mechanical polishing by 3D surface roughness profiler and scanning electron microscope (SEM) analysis, the observation found that the wave of the original test piece rugged, after grinding and polishing wave front and grinding scratches had been removed, and a smooth surface was obtained.