Nonaqueous Slurry Research Articles

Effect of starting materials’ dispersion on the properties of AlN powder synthesized by carbothermal reduction and nitridation

This study examined the effects of starting material dispersion on the formation of AlN powder synthesized by carbothermal reduction-nitridation (CRN) route. After preparing aqueous and non-aqueous slurries containing 6.5 vol % of Al2O3 and carbon black powder with/without a dispersant, the particle dispersion was evaluated by sedimentation and viscosity measurements. The zeta potential was also measured to determine the optimal dispersion conditions for electrostatic repulsion because carbon black is challenging to disperse in water, owing to its low surface charge and poor wettability. The aqueous slurry prepared with 5 wt % Gen0451 dispersant at pH = 10 showed the highest degree of dispersion. Complete AlN conversion was achieved by nitridation at 1600 °C for 6 h under 10 L/min N2 flow. This result clearly showed the importance of starting material dispersion on the synthesis of AlN by CRN, demonstrating the feasibility of aqueous processing instead of conventional solvent-based processing.

Influences of Nonaqueous Slurry Components on Polishing 4H-SiC Substrate with a Fixed Abrasive Pad

4H-SiC wafers are more likely to sustain a lower material removal rate (MRR) and severe subsurface damage in conventional chemical mechanical polishing (CMP) methods. To overcome the material removal bottleneck imposed by aqueous chemistry, a high-efficiency polishing of 4H-SiC wafers method by applying reactive nonaqueous fluids to self-sharpening fixed abrasive pads has been proposed in our former research works. Furthermore, to improve the material removal rate and reduce the surface roughness Sa value of 4H-SiC substrates of the Si face, the effect of organic acid, H2O2, and Triton X-100 in nonaqueous slurry on 4H-SiC polishing was investigated. The MRR of 12.83 μm/h and the Sa of 1.45 nm can be obtained by the orthogonally optimized slurry consisting of 3 wt% H2O2, 0.5 wt% Triton X-100 at pH = 3. It is also found that the addition of different levels of oxidant H2O2 and surfactant Triton X-100 components not only increased the MRR of the 4H-SiC substrates of the Si face but also achieved a lower Sa value; in that, the polishing efficiency of the Si side of the 4H-SiC wafers and the surface quality of the 4H-SiC wafers could be effectively improved by the optimization of the polishing slurry.

Performance characterization of freeform finished surfaces of potassium dihydrogen phosphate using fluid jet polishing with a nonaqueous slurry

Potassium dihydrogen phosphate (KDP) and its deuterated analog (DKDP) are unique nonlinear optical materials for high power laser systems. They are used widely for frequency conversion and polarization control by virtue of the ability to grow optical-quality crystals at apertures suitable for fusion-class laser systems. Existing methods for freeform figuring of KDP/DKDP optics do not produce surfaces with sufficient laser-induced–damage thresholds (LIDT’s) for operation in the ultraviolet portion of high-peak-power laser systems. In this work, we investigate fluid jet polishing (FJP) using a nonaqueous slurry as a sub-aperture finishing method for producing freeform KDP surfaces. This method was used to selectively polish surface areas to different depths on the same substrate with removals ranging from 0.16 μm to 5.13 μm. The finished surfaces demonstrated a slight increase in roughness as the removal depth increased along with a small number of fracture pits. Laser damage testing with 351 nm, 1 ns pulses demonstrated excellent surface damage thresholds, with the highest values in areas devoid of fracture pits. This work demonstrates, for the first time, a method that enables fabrication of a waveplate that provides tailored polarization randomization that can be scaled to meter-sized optics. Furthermore, this method is based on FJP technology that incorporates a nonaqueous slurry specially designed for use with KDP. This novel nonaqueous FJP process can be also used for figuring other types of materials that exhibit similar challenging inherent properties such as softness, brittleness, water-solubility, and temperature sensitivity.

Mechanistic difference between Si-face and C-face polishing of 4H–SiC substrates in aqueous and non-aqueous slurries

The traditional aqueous-based polishing slurries have been extensively used in the ultra-precision machining process of SiC substrates, but their processing efficiency remains a major challenge in making SiC wafers with high surface quality. SiC polishing slurries based on non-aqueous solvents have been explored and reported, however, the mechanism for the accelerated SiC material removal rate (MRR) remains unknown. In this work, the Si-face and C-face of the SiC wafer were polished with water and methanol as polishing liquid carriers, respectively. The MRR of Si-face using the methanol-based slurry, can reach 260.9 nm/h, and the polished Si-face surface roughness Ra reduces to 0.150 nm. In contrast, the MRR of Si-face by using the aqueous-based slurry, is 66.8 nm/h, the polished Si-face surface roughness Ra is 0.691 nm. However, the results of MRR and Ra for C-face are opposite. The reaction between the polishing liquid carriers and the atomic structures of Si-face and C-face lead to differences of the MRRs by analyzing contact angle, XPS, and molecular dynamics (MD) simulation results. The newly revealed polishing mechanisms shined light for speeding up the development of SiC polishing slurries based on the specific aspects of the polishing surface of SiC.

Microwave-accelerated regeneration of a non-aqueous slurry for energy-efficient carbon sequestration

We have developed a slurry of basic immobilized amine sorbent (BIAS) and polydimethylsiloxane (PDMS) oil for a CO2 adsorption/desorption process aided by the Microwave-Accelerated Regeneration of a Slurry (MARS). Selective microwave heating of CO2-adsorbed BIAS can accelerate the CO2 desorption flux by 10 times and consume much less energy for sorbent regeneration, compared to thermal heating. Furthermore, the microwave regeneration temperatures of the slurry can be lowered to 65–85 °C. These results indicate that the microwave-accelerated swing method is highly energy-efficient, which can substantially decrease the energy penalty for CO2 capture and downscale the capture process, especially the regeneration equipment. The microwave-assisted non-aqueous capture technology without water and steam use can decrease the cooling duty by 18–48%, compared to the aqueous amine-based capture technology and promote decarbonization in a more sustainable manner.

Battery Performance of FeF3-Vox Cathode with Nonaqueous-Based Natural Polymer Binder

Iron fluoride (FeF3) for LIB is expected as a positive electrode material that contributes to the realization of innovative secondary battery of 500Wh/kg class from the viewpoint of high theoretical capacity (712 mAh / g) and superiority in element strategy (not including rare earth). However, the entire reaction uses not only an intercalation reaction process that is common to conventional lithium ion batteries but also a conversion reaction process. Therefore, it is difficult for conventional binders (such as PVdF) to deal with volume changes associated with charge / discharge reactions that are characteristics of this material, to disperse conductive carbon, and to produce thick-coated electrodes. Previously we have reported a natural polymer as a binder suitable both for LIB positive and for negative electrodes in a nonaqueous slurry [1]. In this report, we examined the applicability of our binder to FeF3 cathode materials and vanadate glass (VOx), which is a candidate cathode material for innovative storage batteries. A slurry was prepared using a non-aqueous natural polymer binder (NP binder) with a positive electrode active material obtained by mechanical milling of iron fluoride and carbon conductive material. PVdF was used as an electrode binder for comparison. For the peel strength test, the 90 ° peeling method was performed in 15 mm of the tape adhesive surfaces . LiPF6 / EC + PC was mainly used as the electrolyte. A coin-type cell (CR2032) was fabricated with the prepared electrodes, separator and lithium foil. The characteristics were evaluated by various electrochemical measurements. The cells with vanadate glass and composite systems were also prepared and evaluated. All electrode fabrication steps were performed in a dry room with a dew point of −55 ° C or lower, and all cells were constructed in a glove box under an argon atmosphere with a dew point of −60 ° C or lower.Figure 1 shows the charge-discharge curves of an electrode with FeF3/NP binder. The cell using NP binder did not deteriorate rapidly during the first 5 cycles, and stable charge / discharge characteristics were obtained. The cycle evaluation will be continued as the multi-cycle performance. In order to solve the rapid deterioration of the capacity of FeF3, combined use of it with another active material possessing excellent cycle performance has been proposed. Here, we focus on the selection of an appropriate binder for the VOx, another positive electrode active material, which is expected as a combination candidate. Figure 2 shows the cycle characteristics evaluation using NP binder suitable for the VOx system. The cycle performance and coulomb efficiency are quite stable compared with the FeF3-based cathode material. These results suggest that the new natural polymer binder can be applied to FeF3-VOx cathode. However, the capacity development is lower than the theoretical capacity of 500 mAh/g. Thus, optimization of the amount of binder and conductive additive would be necessary. In the poster session, we discuss the binder optimization conditions for these materials, and report the correlation between the peel strength and the characteristics of the composite cathode. This work was supported by NEDO RISING2 project (JPNP16001)[1] K. Soeda, M. Ishikawa, The 19th International Meeting on Lithium Batteries (IMLB2018), Kyoto, Japan, 17-22 June 2018.

Application of Natural Polymer Binder for Nonaqueous Slurry to FeF3-Vox-Based Lib’s Positive

Iron fluoride (FeF3) for LIB is expected as a positive electrode material that contributes to the realization of innovative secondary battery of 500Wh/kg class from the viewpoint of high theoretical capacity (712 mAh / g) and superiority in element strategy (not including rare earth). However, the entire reaction uses not only an intercalation reaction process that is common to conventional lithium ion batteries but also a conversion reaction process. Therefore, it is difficult for conventional binders (such as PVdF) to deal with volume changes associated with charge / discharge reactions that are characteristics of this material, to disperse conductive carbon, and to produce thick-coated electrodes. Previously we have reported a natural polymer as a binder suitable both for LIB positive and for negative electrodes in a nonaqueous slurry [1]. In this report, we examined the applicability of our binder to FeF3 cathode materials and vanadate glass (VOx), which is a candidate cathode material for innovative storage batteries. A slurry was prepared using a non-aqueous natural polymer binder (NP binder) with a positive electrode active material obtained by mechanical milling of iron fluoride and carbon conductive material. PVdF was used as an electrode binder for comparison. For the peel strength test, the 90 ° peeling method was performed in 15 mm of the tape adhesive surfaces . LiPF6 / EC + PC was mainly used as the electrolyte. A coin-type cell (CR2032) was fabricated with the prepared electrodes, separator and lithium foil. The characteristics were evaluated by various electrochemical measurements. The cells with vanadate glass and composite systems were also prepared and evaluated. All electrode fabrication steps were performed in a dry room with a dew point of −55 ° C or lower, and all cells were constructed in a glove box under an argon atmosphere with a dew point of −60 ° C or lower.Figure 1 shows the charge-discharge curves of an electrode with FeF3/NP binder. The cell using NP binder did not deteriorate rapidly during the first 5 cycles, and stable charge / discharge characteristics were obtained. The cycle evaluation will be continued as the multi-cycle performance. In order to solve the rapid deterioration of the capacity of FeF3, combined use of it with another active material possessing excellent cycle performance has been proposed. Here, we focus on the selection of an appropriate binder for the VOx, another positive electrode active material, which is expected as a combination candidate. Figure 2 shows the cycle characteristics evaluation using NP binder suitable for the VOx system. The cycle performance and coulomb efficiency are quite stable compared with the FeF3-based cathode material. These results suggest that the new natural polymer binder can be applied to FeF3-VOx cathode. However, the capacity development is lower than the theoretical capacity of 500 mAh/g. Thus, optimization of the amount of binder and conductive additive would be necessary. In the poster session, we discuss the binder optimization conditions for these materials, and report the correlation between the peel strength and the characteristics of the composite cathode. This work was financially supported by RISING2 project by NEDO and METI. [1] K. Soeda, M. Ishikawa, The 19th International Meeting on Lithium Batteries (IMLB2018), Kyoto, Japan, 17-22 June 2018.

(Invited) Designing Electrodes with Low Tortuosity Pores By Freeze Tape Casting

The tortuosity of pores in composite electrodes for conventional lithium-ion batteries (LIBs) or “beyond lithium-ion batteries” is an extremely important parameter for optimizing performance. The lower the tortuosity, the shorter the path lengths that ions have to travel, which should result in better rate capability and charge acceptance. By using a method known as freeze tape casting (FTC), we are able to design electrodes with nearly unidirectional pores approximately normal to the film thicknesses. In this technique, an aqueous or non-aqueous slurry containing materials of interest is tape cast over a bed set at a temperature below the freezing point of the solvent. As the solvent freezes, the ice crystals that form exclude the solid particles, which segregate into columns. A freeze-drying step removes the ice, leaving behind the porous structure. In the case of conventional composite battery electrodes meant for use in cells with liquid electrolytes, the active materials, binder, and conductive additives can be cast together, similar to what is done by conventional tape casting. For solid-state batteries, a ceramic ionically conducting scaffold is first formed by the FTC process and then sintered to strengthen the pore walls. The scaffold is then infiltrated with active material and other components to form the electrode. In both types of systems, the film thickness, porosity, pore size and shape, and column thickness can be adjusted over a wide range by varying experimental parameters such as temperature, loading, and solvent type. For this talk, we will present several examples from our recent work including solid-state batteries using Li7La3Zr2O12 (LLZO) electrolytes, LIB graphite anodes for fast-charge applications, and sulfur electrodes for lithium/sulfur batteries.

Study on rheological behavior of Micro/Nano-silicon Carbide Particles in Ethanol by Selecting Efficient Dispersants.

A colloidal stability study of a nonaqueous silicon carbide suspension is of great significance for preparing special silicon carbide ceramics by colloidal processing. In this paper, three different chemical dispersants, which are amphiphilic, acidophilic, and alkaliphilic, are selected to compare their ability to stabilize nonaqueous slurries of silicon carbide. The analysis of the flow index factor is first used to estimate the colloidal stability of the suspensions. The results show that the addition of only 5 wt.% polyvinylpyrrolidone (PVP) forms a silicon carbide slurry with a low viscosity value of 17 mPa⋅s at 25 s−1. In addition, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS)measurements indicate that the PVP molecule is successfully adsorbed on the surface of silicon carbide. The different adsorption models are fitted, and the adsorption of PVP molecules on the surface of silicon carbide belongs to the Langmuir single-layer adsorption model. At the optimal PVP amount, the volume content of the suspension is as high as 22.27 vol.%, a Newtonian-like fluid still appears, and no agglomerate structure is formed in the system. After the volume content exceeds 22.27 vol.%, the flow index factor of the slurry begins to plummet, indicating that the slurry begins to transform from a Newtonian-like fluid to a shear-thinning fluid. The particles undergo inevitable agglomeration accompanied by the emergence of yield stress. Finally, a maximum solid loading of the system is predicted to be 46 vol.%, using the Krieger-Dougherty model.

Agglomeration of fine particles in water upon application of DC electric field

The influence of the properties of a slurry on the flocculation behaviour of fine particles in water upon the application of a DC electric field was investigated. In addition, the mechanism whereby particles in water can be flocculated through the application of the DC electric field was clarified. The particle flocculation efficiency was determined for aqueous and non-aqueous slurries to which a DC electric field was applied, by measuring the change in the turbidity of the sampled slurry.It is shown that, for aqueous slurries, the particle flocculation could be enhanced by applying a DC electric field provided the particles carried a charge and were surrounded by an electric double layer. It was also found that there was no enhancement of the flocculation for those slurries for which pH = pHIEP, as well as for non-aqueous slurries using rapeseed oil as their solvent, in which case the particles were not charged. In addition, merely stirring the slurry (thus increasing the number of particle collisions) did not cause the particles to flocculate, although the particle flocculation could be enhanced by applying a DC electric field while stirring the slurry, thus maintaining a constant particle concentration.These findings lead to the conclusion that the enhancement of the particle flocculation in an aqueous slurry through the application of a DC electric field is caused by the charged particles and their counter ions in an electric double layer forming an electric dipole due to the deformation of the electric double layer, thus creating an electrostatic attractive force between the particles.

Effect of polyethyleneimine-fatty acid complex type dispersant structure on the overall processing chain of Si3N4 ceramics using multicomponent non-aqueous slurries

The effect of fatty acid structure of polyethyleneimine (PEI)-fatty acid complex, which was designed as a polymer dispersant for multi-component non-aqueous slurries, on the overall processing chain of Si3N4 ceramics involving slurry stabilization, spray drying, compaction, and liquid sintering was investigated using PEI-oleic acid (PEI-OA) and PEI-isostearic (PEI-ISA) complexes. Si3N4-Y2O3-Al2O3-AlN-TiO2/toluene slurries were selected as a real model for Si3N4-based multicomponent slurries. It was observed that both PEI-OA and PEI-ISA can stabilize Si3N4-Y2O3-Al2O3-AlN-TiO2/toluene slurries; however, the PEI-ISA system tended to have slightly higher slurry viscosity, which was suspected to be due to the interactions between protruded PEI segments among short ISA chains. The spray-dried granules from PEI-ISA-stabilized slurry were observed to have filled structures with higher surface roughness whereas those prepared from PEI-OA-stabilized slurry were observed to have hollow-structured granules. The granules prepared from PEI-OA slurry had improved flow and compaction properties with higher relative density of green compacts compared with those prepared from PEI-ISA-stabilized slurry, whereas the relative density and microstructural homogeneity of S3N4 ceramics sintered at 1600 °C for 2 h were observed to be higher for the PEI-ISA system. It is suspected that PEI-OA effectively improved the dispersion stability of multicomponent slurries and flow/compaction properties of granules; however, the inhomogeneous microstructures of green compacts induced by the hollow-structured granules had an adverse effect on the sintering of Si3N4 ceramics.

Microstructural control of green bodies prepared from Si-based multi-component non-aqueous slurries and their effects on fabrication of Si3N4 ceramics through post-reaction sintering

A Si-based slurry containing Si particles covered with Y2O3 and MgO nanoparticles (NPs) has been successfully prepared and then applied to shape Si-based green compacts for the fabrication of silicon nitride (Si3N4) ceramics via post-reaction sintering. It was found that Y2O3 and MgO NPs modified with polyethyleneimine-oleic acid complex (PEI-OA) could be effectively attached to Si particles by simple mixing in dense toluene slurry. Field emission scanning electron microscopy observations confirmed the attachment of PEI-OA-modified sintering aids to Si particles without forming large NP agglomerates. The adsorption of the PEI-OA-modified sintering aids and PEI-OA on the surface of Si particles drastically improved the stability of the Si-based toluene slurry, which was subsequently molded through wet vacuum casting and dewaxed to fabricate a Si-based green body. The obtained green body was nitrided at 1375 °C for 4 h at a N2 pressure of 0.15 MPa and further sintered at 1850 °C for 2 h at a N2 pressure of 0.9 MPa. The adsorption of sintering aid particles on the Si surface reduced the number of contact points between Si particles in the green body, which effectively suppressed the Si melting process during nitriding and improved the characteristics of the produced nitride body such as the degree of nitriding and α/(α+β) ratio of Si3N4, leading to the successful fabrication of high-density Si3N4 ceramics during the subsequent densification step.

Manufacture and characterization of oxide ceramic matrix composites out of commercial pre-impregnated fabrics

In this work, a recent production technique of oxide ceramic matrix composites with a porous matrix based on commercial prepregs from Axiom, USA, was developed and investigated. The main objectives were to study the influences of the different prepreg types and the manufacturing process on the material properties. Two commercially available prepregs – Nextel™ 720 fabric with alumina-silica matrix based on a non-aqueous slurry and Nextel™ 610 with alumina matrix based on an aqueous slurry – are processed with the simple techniques of laminating, warm pressing, drying and sintering. The manufacturing process has been defined on one hand based on the prepreg manufacturer’s recommended curing cycle as well as based on thermogravimetric analysis. On the other hand, standard-processes from own know-how were used which are based on the wet layup technique with fabrics infiltrated by hand. The manufacturer of the prepreg recommended curing via warm compression or autoclave process. The autoclave process has been pushed aside in order to significantly reduce production costs. The matrix composition has been analyzed after different processing steps. Bending and shear tests showed the influence of the different prepregs and thermal treatment on mechanical properties. Based on experimental results from microstructural analysis and mechanical testing, it was shown that prepregs out of alumina fabric with an aqueous alumina matrix are suitable for the production of the all-oxide CMCs.

Fabrication of Nd:YAG transparent ceramics by non-aqueous gelcasting and vacuum sintering

Highly transparent Nd:YAG ceramics were fabricated by non-aqueous gelcasting and vacuum sintering for the first time, using epoxy resin and polyamine curing agent as gelling system. The influences of dispersant, solid loading and the organics of gelling system on the viscosity of suspensions and the stability of suspensions were discussed. The optimized nonaqueous slurry was of 54vol% solid loading, comprising the commercial α-Al2O3, Nd2O3 and Y2O3 powders. The slurry with low viscosity and good fluidity was obtained by using 0.45wt% PEI as dispersant. The homogenous and dense green body was obtained through solidificating the slurry in-situ. The green body after burnout had a relative density of 55.0% with a narrow pore size distribution. The transmittance of the Nd:YAG ceramics sintered at 1775°C for 30h with the thickness of 1.5mm reached 83% at 1064nm. The average grain size of the sample was about 71μm.

Polyethyleneimine–Oleic Acid Complex as a Polymeric Dispersant for Si3N4 and Si3N4-Based Multicomponent Nonaqueous Slurries

Polymeric dispersants that adsorb onto various types of fine particles have been designed through complex formation between cationic polyethyleneimine (PEI) and anionic oleic acid (OA) to improve particle surface compatibility with nonaqueous solvents. Complex formation involves the OA-assisted dissolution of PEI in a nonaqueous solvent (toluene) by ultrasonication. While PEI itself is immiscible in toluene, various molecular weights (MWs) of PEI (Mw = 600, 1800, and 10 000) visibly dissolved when, in the presence of more than 5-mol % PEI (based on the ethyleneimine (EI) unit of PEI), a complex formed between the carboxyl group of OA and the amines of PEI in toluene. Si3N4 and one of the typical multicomponent compositions for Si3N4 ceramic fabrication, Si3N4–Y2O3–MgO, were chosen to demonstrate the usage of PEI–OA complexes for improving nonaqueous slurry stability. While nontreated Si3N4 particles rapidly formed dense slurry aggregates followed by solidification in toluene, PEI associated with 30 mol % OA effectively adsorbed on Si3N4 fine particles and drastically improved the flow properties with ∼1.8 mg/m2 treatment. Surprisingly, the flow properties were maintained even for dried and redispersed slurries. The effect of the MW of PEI–OA and its additive content on the stability of Si3N4/toluene slurries has been clarified, and their applicability toward Si3N4–Y2O3–MgO multicomponent systems is discussed.

Tape casting of cobalt ferrite from nonaqueous slurry

This paper describes the fabrication of CoFe2O4 thick films using the tape casting method from nonaqueous slurry. CoFe2O4 particles with average size of ∼800nm were prepared by the solid-state reaction method. Sediment volumes and viscosity were tested to study the effects of dispersant in reducing aggregations in slurry. Slurry with 0.25wt% dispersant amounts and 41.3wt% solid content showed the optimal stability and rheological properties. A tape velocity of 8cm/s was used in this study considering the non-Newtonian flow behavior at low shear rate. CoFe2O4 ceramic films sintered at 1150°C for 2h have dense structure (relative density of 94%) and exhibited ferromagnetic properties with in-plane saturation magnetization of ∼324emu/cm3.

Preparation of Non-Aqueous Mg Green Tapes by Tape Casting

Mg green tapes by tape casting were prepared. The effects of different powder size and shape, solid loading, the content of binder, and the binder to plasticizer ratio on non-aqueous Mg slurry for tape casting and green tapes were investigated. The rheological behavior of Mg slurry and microstructure of green tapes obtained in different conditions were analyzed. The results demonstrated that Mg powders, with smaller size 27.32 μm, sphericity, were suitable for preparation of slurry with low viscosity and green tapes with higher density. The optimum solid loading, binder content, and binder to plasticizer ratio for Mg slurry and compact green tape were respectively 55 wt%, 3.2 wt%, and 3.75. Mg slurry belonged to Bingham plastic flow and were suitable for tape casting.

Fabrication of highly particle-oriented alumina green compact from non-aqueous slurry

A highly textured alumina green compact was obtained from well dispersed non-aqueous slurry by drying it in a high magnetic field. Compatibility of poly(vinyl butyral) (PVB) as a dispersant and organic solvent was optimized in order to control the conformation of PVB which affects the dispersion state by steric repulsion. A novel observation method was developed to analyze the structure of dispersed particles in concentrated slurry with an optical microscope. This method clarified that well dispersed slurry based upon good compatibility of PVB and organic solvent led to a highly particle-oriented green compact.

Direct observation of particle dispersion patterns in non-aqueous slurries using an in-situ solidification technique

Direct observation of particle dispersion patterns in non-aqueous slurries using an in-situ solidification technique

Preparation of the Barium Strontium Titanate/Magnesium Oxide Plates by Non-Aqueous Gel-Casting

Barium strontium titanate/magnesium oxide composite ceramic plates were prepared by non-aqueous gel-casting using barium strontium titanate and MgO as the raw materials. The rheological properties of the non-aqueous slurries, the dosages of the catalyst and initiator, micro structures and phase structures of the sintering ceramic plates were investigated and analyzed. The results showed that the slurry with solid content of 50wt% in non-aqueous gel-casting had excellent rheological properties and operating characteristics. Ba0.6Sr0.4TiO3/MgO plates with a smooth surface and dense structure were fabricated through desiccation and sintering at 1300°C, and the relative density is up to 4.14g/cm3. The polished surface of the ceramic substrate was composed of 35% MgO and 65% Ba0.6Sr0.4TiO3, and the content of Ba0.6Sr0.4TiO3 was obviously higher compared to the content in the raw materials which was explained by the phenomena of surface phase enrichment.