Inorganic-organic flexible hard-coat films on PET (Poly(ethylene terephthalate)) films were prepared by sol-gel method. Prepared hard-coat films had hight transmittance because main component was SiO₂. And the films had not only high flexibility but also hardness (3H, Pencil Hardness). This novel property thought to be based on dispersion of inorganic and organic components at a molecular level.

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A newly proposed SiO2-Al2O3-TiO2 ceramic coating slurry was deposited on a steel plate for the purpose of examining thermal stability. The coated films were found to be stable up to 700 °C in air, while were exfoliated from substrate beyond 800 °C. On the other hand, the calcination at 1100 °C in N2 atmosphere gave a good adhesion. It was also found that the coated films calcined in N2 atmosphere were stuck to substrate after re-calcined at 900 °C in air.

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In this research, we examined the reaction characteristics between the hydrogen sulfide gas and the lead content fritted colors. And, we obtained various reaction characteristic test results. Especially, Hunter whiteness values (w) of the all colors samples fell down, and all colors deteriorated. However, the discoloration degree of the colors used with the environment correspondence functional frit, were weak in the case compared with the others.

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In this study, the improvement in compressive strength of matrix part in the system of calcium silicate hydrate was aimed by the reduction of the water powder ratio. Further, the morphology and reaction mechanism of autoclaved calcium silicate hydrates in low water powder ratio were studied.

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Hydration of C₁₂A₇ with or without phosphoric acid and the change for phase condition of the hardened paste in water and simulated body fluid (SBF) were studied. The hydration of C₁₂A₇ was delayed by increase in the concentration of phosphoric acid. The concentration of Al in the soaking solution increases with the soaking duration. The dissolution of Ca and Al delayed when the paste contained phosphoric acid or the soaking solution was SBF. The surface of the hardened C₁₂A₇ paste covered crystalline HAp, after soaking SBF for 7days at 37°C.

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We have studied porous pottery with densely dispersed closed pores with some 10 micrometer spheres in diameter for an ultra light-weight pottery. The closed pores were formed by mixing hollow micro spheres in the pottery row materials. Sintering condition was investigated for three kinds of hollow micro spheres. We made clear the formation process of the closed pores and open pores.

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The potential energy surface on the [Ca₃(PO₄)₂]₃ was studied through ab initio calculations. Isomers with T_d, T_h and 2D_3d symmetries was found to be the most appropriate starting points. From these symmetries, 137 different isomers were formed in their subgroups in total. Among the 137 isomers, 67 isomers have at least two operations of symmetry. The bond length and angle of Ca-O within the 67 isomers were optimized. The isomers corresponding to the first, second and third lowest energy calculated are of Cs, S₆ and C₂ symmetry, respectively.

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¹H MAS NMR spectra have been successfully obtained for hydroxyapatite samples heat-treated at temperatures of 200-1200 °C. The intensity of bands around 0 ppm associated with the OH^- ions did not change significantly up to about 800 °C, whereas it decreased at temperatures higher than about 800 °C. The peak shifted into a downfield (a light shielded environment) and the line width increased with increasing temperature at higher than 800 °C. These results are interpreted in terms of disordered environments around the OH^- sites due to creation of defects by dehydration of hydroxyapatite over 800 °C.

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The influences of plasma gas composition on the adhesivensee of HA/Ticomposite coatings were investigated. HA/Ti composite coatings were deposited on titanium substrates by a radio-frequency (RF) thermal plasma spraying method with RF input powers of 10-30 kW. The ratio of HA and Ti powders supplied into the plasma was precisely controlled by two microfeeders so as to change the composition from Ti-rich to HA-rich toward the upper layer in the coatings. The bond strength (tensile) of HA/Ti composite coatings was 40-65 MPa in the case of sprayed in the plasma gas with small content of N2 addition. On the other hand, the HA/Ti composite prepared with pure Ar and O2 addition gave significant lower bond strength that is, under 33 MPa.

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Chondroitin-4-sulfate sodium salts, sodium dodecyl sulfate and polycarbonic acid were added to improve the injection properties and mechanical properties for α-TCP-TeCP-DCPD bone cement system α-tricalcium phosphate and tetracalcium phosphate were prepared by heating a mixture of calcium hydrogen phosphate and calcium carbonate at 1500°C for 6h in furbace followed by quenching at room temperature. The viscosity was decreased by added amount of dispersion agent was increased. In this study, sodium dodecyl sulfate was the most effective material to reduce the viscosity. However setting time was longer when the added amount of dispersion materials was increased. The compressive strength increased when the amount of dispersion agents was increased, because liquid content can be reduced.

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Cellulose/silica composites were prepared by sol-gel method from solutions containing Si(OCH₃)₄ and acetyl cellulose, and the changes of their mechanical properties in a simulated body fluid (SBF) were examined. Both Young’s modulus and the bending strength decreased by soaking in SBF, while the strain at failure increase ; Young’s modulus and bending strength decreased from 2.6 to 1.6 GPa and from 85.8 to 35.0 MPa, respectively.

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Mechanical properties of hot-pressed β-TCP doped with univalent or divalent metal ions were evaluated and the effect of metal ions on the mechanical properties of hot-pressed β-TCP was investigated. Hot-pressed β-TCP achieved a relative density of more than 96.7%. Bending strength of undoped β-TCP was about 110 MPa. β-TCP doped with Mg²⁺ ion up to 10 mol% showed a bending strength of more than 140 MPa, especially β-TCP doped with 8 mol% of Mg²⁺ ion showed a bending strength of 160 MPa. On the other hand, bending strength of β-TCP doped with K⁺ ion gradually decreased from 135 to 85 MPa with increasing the amount of K⁺ ion.

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Compressive strength of calcium phosphate cement (CPC) with 5mass% hydroxyapatite (HAp) powder was investigated. The compressive strength of the CPC with non-polarized and polarized at 300°C HAp powder hardened for 72h were 43.2 and 54.5MPa, respectively.

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Bioactive calcium phosphate bone cement (CPC) has been developed for clinical use. The powder component of CPC consists of α-TCP, TeCP, DCPD, HA and a stabilizer, while the liquid is an aqueous solution containing sodium chondroitin sulfate, sodium succinate, and a stabilizer. The mixture can set within about 10 minutes after mixing in a physiological condition. The mixture also sets in the simulated body fluid (SBF) without severe change in pH and gradually turns into low crystalline carbonated hydroxyapatite. Compressive strength of the hardened body reaches its final strength more than 80MPa in 3 days soaked in SBF at 37°C.

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The negative logarithm of the solubility product (Ksp) of ZnTCP was expressed as pKsp = 28.686+1.7414C-0.42239C²+0.063911C³-0.0051037C⁴+0.0001595C⁵ in air, where C is the zinc content in ZnTCP in mol%. The solubility of ZnTCP, containing 0.63 and 0.316 Zn wt%, decreased to 52-69% of the solubility of pure TCP in the pH range of 5.0-7.4. However, the in vivo resorbed volume of ZnTCP containing the same amount of zinc was as low as 26-20% of that of TCP. The reduction of the resorbability of ZnTCP would be attributable principally to its lowered cellular activation property relative to that associated with pure TCP.

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Calcium phosphate cement in calcium phosphate cement-allograft composite was absorbed considerably in vivo. In order to examine the detailed mechanism, we carried out hydrolysis of calcium phosphate cement-allograft composite in saline and calf serum.

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It is expected that chemically durable ceramic microspheres containing a large amount of yttrium 20-30 μm in diameter are useful for in situ radiotherapy, when they were previously activated to β-emitter by neutron bombardment. In the present study, chemical durability of untreated and acid-treated Y₂O₃ microspheres was investigated in salines buffered at pH-6 and pH-7. It was revealed that Y₂O₃ microspheres show high chemical durability in salines buffered at pH-6 was well as pH-7, when they are previously treated with acid solution. Thus acid-treated Y₂O₃ microspheres are expected to be useful for in situ radiotherapy of deep-seated cancer.

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We have previously reported that apatite cement enhance the differentiation of human osteoblasts. In this investigation, apatite cement and sintered apatite were immersed in simulated body fluid and cell culture medium to understand the factor, which may relate to the cells’ differentiation. We found calcium and phosphate ions in the cell culture medium decreased significantly when apatite cement was immersed in the medium even though the concentration was relatively constant when sintered apatite was immersed in the medium. Although the detailed mechanism has not been clarified, quick formation of bone like apatite may relate to the enhanced differentiation of osteoblasts.

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In order to develop bioactive “tailor-made” materials with desired properties for each patient, two kinds of materials have been created. These are as follows: (i) hydroxyapatite (HAp)/polymer hybrids with mechanical properties similar to those of cortical bone, and (ii) HAp/tricalcium phosphate (TCP)-coated high-strength materials with a porous structure which enables bone ingrowth into the pores. From in vivo evaluation using a rabbit model, it was observed that the above-mentioned materials showed a bioactivity response, that is, the implant materials directly bonded to living bone. We performed an in vitro evaluation using osteoblast cells to help understand the reasons for bioactivityin the in vivo model. The results of in vitro evaluation showed that the two kinds of bioactive materials induce excellent cellular response, including the ability differentiate cells into osteoblasts. This may be the reason for the bioactive response observed in vivo.

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Diopside, CaMgSi₂0₆, is known as an advantageous bioactive material. Particularly, the diopside produced by alkoxide method is crystallized in lower temperature range. Since the rate of hydrolysis of the alkoxides differs considerably from one species to another, the system is heterogeneous. Using not only alkoxide but also inorganic salts as starting materials is, therefore, effective to improve the problems. The present study deals with preparation of diopside by liquid-phase reaction techniques using alkoxide and inorganic salts and the effect of the thermal properties of diopside on the crystallization process and the biological activity of its sintered bodies. Powder X-ray diffraction revealed that the dry powders were X-ray amorphous and crystallized into diopside at lower temperature than that by alkoxide method. The results of thermal measurements suggest that the vaporization of inorganic gases before crystallization promotes the nucleation of diopside. Moreover, the apatite layers were found to form on the diopside surfaces and grow with increasing immersion period in simulated body fluid (SBF).

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Porous Ormosil-type hybrid materials were synthesized by a sol-gel method starting from tetraethoxysilane and polydimethylsiloxane. The pore size of the hybrids were 300 ∼ 600 mm in diameter. The porous hybrids with Ca²⁺ ions deposited apatite particle on the pore surface when soaked in a simulated body fluid (Kokubo solution) for 3 days.

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Ti substrates were provided with in vitro bioactivity by the treatment with 3 mass% H₂O₂ solution and subsequent heat-treatment at 400° C for 1h. Osteoblastic cells (MC3T3-E1) were proliferated on the Ti substrates. We could not find direct correlation of apatite formation to cell proliferation.

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Bioactive ceramic coating was formed on titanium substrates hydrothermally CaTiO₃ layers were prepared on the substrates with mixed solution of Cacl₂ and KOH at 150°C and etched by dilute HCl solution at 20-220°C for 24h. When the etching temperature was over 120°C or the pH was lower than 2.6, anatase was formed. These film have high surface area, had 250-300 times larger than that of titanium substrates. HAp deposited on the film with high surface area that anatase formed after soaking in SBF for 7days at 35°C. The amount of deposited HAp, normalizes with the surface area of the film, was almost constant(1.1 μg/cm²), regardless of the surface area of the film.

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For the purpose of recycling waste colored glass, we attempt to extract alkali and metals from the glass. The soda-lime-silicate glasses are leached in nitric acid after crushing to fine powder or remelting with H₃BO₃. It is found that alkali and metal ions are successfully leached by those treatments. Chemical composition of the glasses thus obtained is also analyzed.

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A process of extraction of SiO₂ from waste colored bottles was investigated, because various utilizations of waste glasses were expected by extracting SiO₂ which is the main component in the bottles. Sample solutions were prepared by alkali fusion of the crushed glasses and the hydroxide (KOH or NaOH). The solutions were boiled after mixing HCl with the solutions, and Si (OH)₄ was then precipitated. After drying the Si (OH)₄ separated from the solution, the SiO₂ powder with purity of 99.75±0.15% was obtained. In addition, the yield of the SiO₂ was also confirmed to be 97-98% by quantitative analysis. From these results, the process of extraction using KOH or NaOH was revealed to have a potential applicability as a recycling process of waste glasses.

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Kira is a wasted material through elutriation process of raw materials of glass and clay. Since it contains quartz and clay, it is expected to be an appropriate raw material in the preparation of glass ceramics. Glasses were prepared by melting powders mixing CaCO₃ to Kira. They were heated at various temperatures for various times to examine crystallization behavior. Wollastonite, pseudowollastonite, anorthite was crystallized in the glass ceramics.

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Glass-ceramic to building material from glass cullet and concrete sludge was investigated. Batches were prepared by mixing a mass ratio of 50∼80 glass cullet, 20∼50 concrete sludge, 0∼30 aluminium oxide, 0∼4 iron sulfide, 0∼4 sodium sulfate, 0∼1 graphite, respectively. Black glass was produced by melting the batch at 1450 °C for 2 hours in a reducing atmosphere, and flowed on a steel plate. To form nucleation, this glass was reheated at 850 °C for 1 hour, and reheated at 1100 °C for 2 hours to form glass-ceramic. Results of the SEM observation and powder X-ray diffraction pattern of glass-ceramic showed wollastonite to be the main crystal, other crystals were nepheline and gehelenite.

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In order to clarify the possibility of the lead fixation by hydrothermal processing, the effect of hydrothermal processing time and temperature on the amount of lead dissolved from fly ash was investigated. The amount of lead dissolved from autoclaved bodies decreased with the increase in processing time and temperature. The lead in specimens was hardly leached during hydrothermal processing. These results suggested the possibility of the lead fixation by hydrothermal processing. The mineral contributed lead fixation was identified by SEM-WDX.

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It is expected that clay minerals and zeolite can be synthesized from burned sluge because it contains Si, Al, Fe. In this study, burned sluge was treated with various salt solution such as NaOH, KOH, HCl, MgCl₂, MgCO₃(basic), AlCl₃, NaAlO₂ at 150, 200, and 250°C for 1 to 10 days. The products were examined by means of XRD. As a result, smectite, kaolinite, vermiculte, mica clay minerals, mix layered smectite-vermiculite, and zeolite were formed.

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Coal fly ashes include silica and alumina. They can be converted into zeolite by alkaline treatment. Seven types of coal fly ashes were mixed with 2.0M NaOH solution and heated at about 100°C for 5h. The products were identified by XRD to be zeolite Na-P and/or zeolite NA_ex K-F. The content of synthesized zeolite depended on the amount of glass phases in the fly ash source. It is found that a high performance zeolite can be synthesized from the fly ash with high Si/Al ratio, small particle size and large amount of glass phases.

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The products from KOH-treated coal fly ash (FA) was systematically examined. Only linde F zeolite was formed under the reaction conditions of the present experiments. The yield of the zeolite from 2 g of FA was highest when reaction time, temperature, KOH concentration and volume were 48 h, 95°C, 8 mol dm^-3 and 50 ml, respectively. In this case, FA spheres were completely dissolved out, and square prisms of linde F zeolite crystal with 0.5 to 2.0μm in width and 1 to a few μm in length were formed. The specific surface area and cation exchange capacity of the product were 2.02m²/g and 2.3 meq g^-1, respectively.

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Resource recovery of industrial waste including iron compounds has been investigated. Consequently, hydrotalcite-like Mg/Fe and Zn/Fe layered double hydroxides were successfully prepared from these waste by wet and hydrothermal methods. In the present work, we report the anion removal properties of resulting materials for nitric phosphoric ions.

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To clarify the effect of activators on adsorption characteristics of the carbon-ceramics porous (CCP) materials prepared from industrial wastes, we investigated the adsorption properties of methylene blue (MB) cations to CCP materials synthesized with various activators added. The CCP material activated with K₂CO₃, KOH, and NaOH exhibited higher absorbability of MB than the CCP without activator. This result indicates that carbon component in the specimen can be activated during calcination at 850°C for 1 hours.

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Blended cements are noticed as countermeasure for the reduction of produced CO₂ gas in production of cement. This paper described the influence of the various type of additive on the hydration and chemical shrinkage of blended cement. The chemical shrinkage of BFS Cement was larger than OPC or other blended cements after 3 days. BFS rapidly reacts compared with the case of other additives. Chemical shrinkage of FA cement is indicated the smallest values, it is because FA didn’t react until 7 days.

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The used SiC powder was heat-treated in N₂ atmosphere in order to recycle the powder after the abrasion of silicon wafer. XRD analysis showed that crystalline Si disappeared by heating the used powder in N₂ atmosphere. The formation of Si-N whiskers was confirmed by SEM-EDS observation. These results suggested that the used SiC powder could be converted into the Si-N whiskers containing SiC powder for sintering.

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It is well know that the mechanical properties of the yttria stabilized zirconia (Y-TZP) is degaaded by hydrothermal treatment. In this study, effect of various acidic solvents on disintegration of Y-TZP under hydrothermal condition was investigated. The Y-TZP sintered body was disintegrated into much finer particles, since hydrochloric or nitric acid effectively proceeded the pahse transformation by extraction of yttrium.

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Ferroelectric performance for ferroelectric material of PbZr_xTi_1-xO₃ changes by heat treatment. We investigated the relation between physical properties, crystal structure and ferroelectric performance of the sample before and after various heat treatment. The crystal structure was determined by Rietveld analysis using neutron powder diffraction data. From the results, Pr of PbZr_xTi_1-xO₃ (x=0.40,0.45), and Ec and Tc of PbZr_xTi_1-xO₃ (x=0.40) increase by annealing at high Po₂. The ferroelectric performance was affected by changing the defect of oxygen.

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Compounds in the SrO-Ta₂O₃-Pr₂O₃ system were synthesized by solid state reaction. No ternary compound was identified. Binary compound of Sr₅Ta_4-yO_15-d was prepared as a single pahse. The electrical conductivity of Sr₅Ta_3.8O_14.5 increased with increasing water vapor pressure, suggesting protonic conduction. The activation energy at lower temperatures was lower than that at higher temperatures. The ionic conduction of binary compound PrTa₃O₉ was observed.

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The oxygen absorption behavior of Ce₂Zr₂O_7+x (0≤x≤1) with an ordered arrangement of Ce and Zr ions was studied by thermogravimetric analysis. The results suggest the presence of intermediate phase with Ce₂Zr₂O_7.5 composition. From the X-ray powder diffraction and electron diffraction analysis, the intermediate phase was found to belong to the space group F43m and to be formed by occupying the half of ordered oxygen vacancies with oxygen ions alternately.

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Homologous compound, (ZnO)_mIn₂O₃(m=integer), has very unique crystal strucure that is composed of the layers of In₂O₃, (InZn)O_2.5 and ZnO periodically stacking along the c-axis direction. In this study, we prepared the textured ceramics of (ZnO)₅In₂O₃ by the reactive templated grain growth (RTGG) technique, and investigated the diffusion proces of In ion on the ZnO block by HRTEM observation.

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Ba, Sr-substituted cubic Cs-leucite compounds were synthesized by a multi-step heating process. Thermal expansion rates at 1173K for the synthesized cubic Cs-leucite compounds decreased with increasing the substituted amount of Ba²⁺ or Sr²⁺ ions. The synthesized Cs_0.675Sr_0.1125Al_0.9Si_2.10₆ showed thermal expansion rate about 0.11% at 1173K, which was much smaller than CsAlSi₂0₆. The thermal expansion rates decreased with increasing space ratio in the unit cell at 298K.

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The reference materials are necessary to evaluate exactly the fundamental properties of materials. We have been studying reference materials on thermal expansion using fine ceramics. In this study it is considered the zirconia (REFERCERAM ZR1) are candidate for the thermal expansion reference materials. Then the homogeneity and the stability of the thermal expansion in these materials were evaluated. As a result, it is clear the zirconia is suitable for reference materials.

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Aluminum titanate (TA) ceramics has low thermal expansion with micro crack due to thermal expansion anisotropy, and so it has low strength. In this study, we made aluminum titanate-mullite composites with different composition. In order to evaluate the characteristic change with composition, we investigated the detailed characteristic using AE count and original waveform time-frequency analysis. The composite of higher rate of TA showed higher AE count peak temperature and since it was small in the difference with standard temperature, it was low in the strength. This was good agreement with the result of three points bending.

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Stress-relief-type mullite-Mo basic multilayered functionally graded material disks (FGM) were fabricated by powder metallurgy technique and the thermal shocking test were carried out using the specimens. Thermal stress developed when thermal shocking, as well as the residual thermal stress generated during sintering process, was calculated. Then the thermal shocking resistance of FGM plates were evaluated by considering the calculated and tested results. The influence of residual thermal stress on the stress distribution when thermal shocking were also evaluated.

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Strength of β” alumina at elevated temperature were evaluated in comparison with mechanical properties and ionic conductivity. The degradation of strength with increasing temperature corresponded to the increasing of ionic conductivity. It is considered that the strength of β” alumina at elevated temperature can be explained by binding force of conduction plane.

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The crystal growth simulation from MgO melts with or without Ca ions was carried out under various conditions. When amorphous MgO melts were simulated at various temperatures, the crystal growth was observed in the vicinity of the vapor-liquid interface. It was not clearly observed that Ca ions added as impurities were concerned in the crystallization.

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The surface characteristics of non oxide ceramics were investigated through the heat of immersion in water by means of Calvet type calorimeter. Following materials were examined in this study: uncovered silicon nitride and silicon carbide powders(rinsed with hydrogen fluoride), surface oxidized silicon nitride and silicon carbide powders(treated in a heated oxygen atmosphere), amorphous silica and quartz silica powders. The value of the heat of immersion of silicon nitride had approached to that of amorphous silica by surface oxidation.

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It is important to test the quality of slurry in many industries such as ceramics, emulsion and so on. It is because the quality of ceramics products can be predicted by the test of slurry. In this study the influence, which the sample mixing speed has on the attenuation, became clear.

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EGA-MS (Evolved Gas Analysis-Mass Spectrometry has been applied to investigation of pyrolysis behavior on raw materials of alumina ceramics. Pyrolysis temperature of polyvinyl alkohol as binder is lower than that of acrylic resin for pore formation. As gaseous species evolved by pyrolysis, characteristic fragments were also detected.

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Effect of coarse agglomerated particles on slip-casting alumina was analyzed. Alumina ceramics with a very small amount of coarse agglomerated particles was fabricated through slip-casting process. The ceramics strength was examined and fracture orgin was observed with SEM. The structure of green and sintered bodies were examined by direct observation techniques.

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