Info-Convergence Ceramic Nanosystems

Jin, Wenji,Park, Dae-Hwan The Korean Ceramic Society 2019 한국세라믹학회지 Vol.56 No.5

We face many fascinating and diverse challenges, the most important among which is to determine how to store a large amount of information with novel approaches. Info-convergence ceramic nanosystems, which combine ceramic materials science and information technology, may provide an attractive alternative. This review considers recent multidisciplinary advances in the development of info-convergence nanosystems based on ceramic materials and discusses various strategies under ceramic-based information systems with a special focus on materials and nanohybridization technologies. Ceramic materials have played diverse roles not only as the generic coding support, but also as the central coding substance. The review highlights the ceramic nanohybrid bio code and ceramic nanoparticle optical code for applications in tracking-and-traceability management, nano-forensics, anti-counterfeiting, and even communication, as well as the four steps of encoding, encrypting, decrypting, and decoding for the desired applications. Additionally, associated challenges, potential solutions, and perspectives for future developments in the field are discussed.

Ceramic - Polymer Nanocomposite: Alternate Choice of Bone

Sarkar, Debasish,Chu, Min-Cheol,Cho, Seong-Jai The Korean Ceramic Society 2008 한국세라믹학회지 Vol.45 No.6

This study evaluates a range of materials that may be used to design prostheses for bone. It is found that nanocrystalline ceramic-polymer composite could be the best material for prosthetic bone with respect to biocompatibility, morphology, chemistry, and compatibility with the piezoelectric and mechanical behavior of long human bones, such as the femur.

Ceramic Materials having Strain Sensing Properties -The CaO-NiO Ceramics-

Seo, Sato-Shi The Korean Ceramic Society 1999 The Korean journal of ceramics Vol.5 No.2

The strain sensing properties of th system xNiO-(1-x) CaO with various compositions (x=0.001-0.05) are evaluated and the origin of the phenomena is guessed. We have found out that the high temperature electrical conductivity of the xNiO-(1-x)CaO increases by applying the compressive stress at $1000^{\circ}C$. When the applied load is removed, the electrical conductivity rapidly decreases and returns to the original value, but a small hysteresis of the stress-conductivity curve is observed. After the loading test, the lattice parameter of the specimen is found lengthened. The correlation between the lengthening of the lattice parameter and the increases in the electrical conductivity by loading is discussed. The amount of the "expanded type" Ni(II)O6 clusters in the xNiO-(1-x)CaO grains is supposed to be increased by the applied stress, which would be the origin of the strain dependent electric conduction in the xNiO-(1-x)CaO system.aO system.

Multiple Scale Processes in Microstructural Evolution: Case Study of Self-Reinforced β-Si₃N₄

Becher, Paul F. The Korean Ceramic Society 2016 한국세라믹학회지 Vol.53 No.6

Microstructural design of ceramics has generally focused on information gathered at the micro- and macro-scales and related this to how specific properties could be improved. Ceramic processing serves as the key to optimizes the final microstructure. However, the advent of nano-scale microstructures and highly advanced characterization tools are forcing us to develop new knowledge of what is occurring not just at the micro-scale but also at the atomic level. Thus we are now beginning to be able to address how microstructure is influenced by events at the atomic scale using atomic scale images and data. Theoreticians have joined us in interpreting the mechanisms involved in the "microstructural" evolution at multiple scales and how this can be used to enhance specific properties of ceramics. The focus here is on delving into the various layers the "microstructure" in order understand how atomic-scale events influence the structure and properties of ceramics.

Synthesis and Performance Evaluation of Linear Polycarboxylate Dispersant of Glacial Acrylic Acid - Maleic Acid- Sodium Methallyl Disulfonate for Ceramics

Kommanapalli, Kiran Kumar,Lyot, Pierre,Sunkara, Jhansi Rani,Checule, Pierrick The Korean Ceramic Society 2018 한국세라믹학회지 Vol.55 No.2

Using aqueous solution free radical polymerization with glacial acrylic acid (GAA), maleic anhydride (MA) and sodium methallyl disulfonate (SMADS), a novel linear polycarboxylate dispersant was synthesized for ceramics. Dispersant linear structural characterization was done by FTIR, $^1H$ NMR, HPLC and GPC, and the ratio of monomers was determined using an orthogonal experiment. This research is focused on the effects of polymerization temperature, monomer mole ratios and dosage of initiator on ceramic slurry viscosity with linear polycarboxylate dispersant for ceramic dosage rate of 0.30% (based on dry slurry), all of which were investigated by single factor test. The best polymerization conditions for linear GAA-MA-SMADS are when n(AA) : n(MA) : n(SMADS) equals 3.0 : 1.0 : 0.5, the molecular weight of the polymer is 4600 daltons, the initiator sodium persulfate accounts for 7% of the total mass of polymerized monomers, the polymerization temperature is $90^{\circ}C$ and the reaction time is 2 h. The ceramic body slurry viscosity drops from $820mPa{\cdot}s$ to $46mPa{\cdot}s$ when the concentration of the polycarboxylate dispersant is 0.30%.

Three Dimensionally Ordered Microstructure of Polycrystalline TiO₂ Ceramics with Micro/meso Porosity

Chang, Myung Chul The Korean Ceramic Society 2016 한국세라믹학회지 Vol.53 No.2

In order to make a highly ordered three-dimensional porous structure of titania ceramics, porogen beads of PS [Polystyrene] and PMMA [poly(methylmetacrylate)] were prepared by emulsion polymerization using styrene monomer and methyl methacrylate monomer, respectively. The uniform beads of PS or PMMA latex were closely packed by centrifugation as a porogen template for the infiltration of titanium butoxide solution. The mixed compound of PS or PMMA with titanium butoxide was dried and the dry compacts were calcined at $450^{\circ}C-750^{\circ}C$ according to the firing schedule to prepare micro- and meso- structures of polycrystalline titania with monodispersed porosity. Inorganic frameworks composed of $TiO_2$ were formed and showed a three Dimensionally Ordered Microstructure [3DOM] of $TiO_2$ ceramics. The pulverized particles of the $TiO_2$ ceramic skeleton were characterized using XRD analysis. A monodispersed crystalline micro-structure with micro/meso porosity was observed by FE-SEM with EDX analysis. The 3DOM $TiO_2$ skeleton showed opalescent color tuning according to the direction of light.

Ceramic Ink-jet Printing on Glass Substrate Using Oleophobic Surface Treatment

Lee, Ji-Hyeon,Hwang, Hae-Jin,Kim, Jin-Ho,Hwang, Kwang-Taek,Han, Kyu-Sung The Korean Ceramic Society 2016 한국세라믹학회지 Vol.53 No.1

Ink-jet printing has become a widespread technology with the society's increase in aesthetic awareness. Especially, ink-jet printing using glazed ceramic ink can offer huge advantages including high quality decoration, continuous processing, glaze patterning, and direct reproduction of high resolution images. Recently, ceramic ink-jet printing has been rapidly introduced to decorate the porcelain product and the ceramic tiles. In this study, we provide an effective method to apply ceramic ink-jet decorations on the glass substrates using a oleophobic coating with perfluorooctyl trichlorosilane. The ink-jet printed patterns were much clearer on the oleophobically coated glass surface than the bare glass surface. The contact angle of the ceramic ink was maximized to the value of $64.0^{\circ}$ on the glass surface, when it was treated with 1 vol% PFTS solution for 1 min. The effects of the printing conditions and firing process on the ink-jet printed patterns on the oleophobically coated glass were also investigated.

Effect of MnO₂ Addition on Microstructure and Piezoelectric Properties of 0.95(Na_0.5K_0.5)NbO₃-0.05CaTiO₃ Piezoelectric Ceramics

Kim, Jong-Hyun,Seo, In-Tae,Hur, Joon,Kim, Dae-Hyeon,Nahm, Sahn The Korean Ceramic Society 2016 한국세라믹학회지 Vol.53 No.2

$MnO_2$ was added to the $0.95(Na_{0.5}K_{0.5})NbO_3-0.05CaTiO_3$ (NKN-CT) ceramics in order to promote the densification and improve the poling efficiency by increasing the resistance of the specimens. Densification and abnormal grain growth occurred in the $MnO_2$-added NKN-CT ceramics sintered at $1020^{\circ}C$, indicating that $MnO_2$ assisted the liquid-phase sintering of these materials. $Mn^{3+}$ ions were considered to enter the A-site of the matrix, thereby producing the free electrons, which interacted with the holes resulting from the evaporation of alkali ions. This interaction results in an increase in the resistance of the specimens. The increased resistance improved the poling efficiency and, hence, the dielectric and piezoelectric properties of the NKN-CT ceramics. A few of the $Mn^{3+}$ ions that entered the B-site of the NKN-CT matrix led to a slight increase in the mechanical quality factor.

Flexural Strength of Polysiloxane-Derived Strontium-Doped SiOC Ceramics

Eom, Jung-Hye,Kim, Young-Wook The Korean Ceramic Society 2015 한국세라믹학회지 Vol.52 No.1

The effect of Sr addition on the flexural strength of bulk SiOC ceramics was investigated in polymer-derived SiOC ceramics prepared by conventional hot pressing. Crack-free, dense SiOC discs with a 30 mm diameter were successfully fabricated from commercially available polysiloxane with 1 mol% strontium isopropoxide derived Sr as an additive. Agglomerates formed after the pyrolysis of polysiloxane led to the formation of domain-like structures. The flexural strength of bulk SiOC was strongly dependent on the domain size formed and Sr addition. Both the minimization of the agglomerate size in the starting powders by milling after pyrolysis and the addition of Sr, which reinforces the SiOC structure, are efficient ways to improve the flexural strength of bulk SiOC ceramics. The typical flexural strength of bulk Sr-doped SiOC ceramics fabricated from submicron-sized SiOC powders was ~209 MPa.

Microwave Sintering of Graphene-Nanoplatelet-Reinforced Al₂O₃-based Composites

Ai, Yunlong,Liu, Ying,Zhang, Qiuyu,Gong, Yuxing,He, Wen,Zhang, Jianjun The Korean Ceramic Society 2018 한국세라믹학회지 Vol.55 No.6

In this study, we performed a microwave sintering (MWS) of $Al_2O_3$ ceramic and $Al_2O_3$-based composites with nominal contents of graphene nanoplatelets (GPLs) of 0.2, 0.4, 0.6, and 0.8 vol%. The GPL dispersion in N-methyl pyrroleketone was optimized to deagglomerate the GPLs without damaging their structure. Dense composites were then obtained by MWS at $1500^{\circ}C$ for 30 min. The effects of different GPL contents on the phase compositions, microstructures, and mechanical properties of the composites were investigated. The microstructures of the composites became finer with the incorporation of the GPLs. The well-dispersed GPL fillers led to higher sintered densities in the composites. The optimal mechanical properties were achieved with 0.4 vol% GPLs. For this sample, the hardness, fracture toughness, and bending strength were $2000kgf/mm^2$, $6.19MPa{\cdot}m^{1/2}$, and 365.10 MPa, respectively. The addition of GPL could improve the microstructure of the $Al_2O_3$ ceramic and has potential to improve the fracture toughness of the ceramics.