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  • 1
    Electronic Resource
    Electronic Resource
    High-Temperature Phase Relations in the Sc2O3-Ta2O5 System (1999)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 82 (1999), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The phase relations for the Sc2O3-Ta2O5 system in the composition range of 50-100 mol% Sc2O3 have been studied by using solid-state reactions at 1350°, 1500°, or 1700°C and by using thermal analyses up to the melting temperatures. The Sc5.5Ta1.5O12 phase, defect-fluorite-type cubic phase (F-phase, space group Fm3m), ScTaO4, and Sc2O3 were found in the system. The Sc5.5Ta1.5O12 phase formed in 78 mol% Sc2O3 at 〈1700°C and seemed to melt incongruently. The F-phase formed in ∼75 mol% Sc2O3 and decomposed to Sc5.5Ta1.5O12 and ScTaO4 at 〈1700°C. The F-phase melted congruently at 2344°± 2°C in 80 mol% Sc2O3. The eutectic point seemed to exist at ∼2300°C in 90 mol% Sc2O3. A phase diagram that includes the four above-described phases has been proposed, instead of the previous diagram in which those phases were not identified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1999.tb01962.x
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  • 2
    Electronic Resource
    Electronic Resource
    Spherical Aluminum Nitride Fillers for Heat-Conducting Plastic Packages (2005)
    Oxford, UK : Blackwell Science Inc
    Journal of the American Ceramic Society 88 (2005), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: It is necessary for encapsulants to have not only a suitable coefficient of thermal expansion (CTE) compatible to IC devices and a low dielectric constant to reduce the device propagation delay, but also a high thermal conductivity to dissipate large amounts of heat from power-hungry, high-speed IC and high-density packages. Fillers such as silica have been mixed with polymers to improve their properties. Aluminum nitride (AlN) is considered as an alternative one, because it has a higher theoretical thermal conductivity of ∼320 W/mK1, a compatible CTE with silicon chips and a low dielectric constant. Commercial AlN fillers are angular in shape, because they are prepared via grinding coarse AlN powders synthesized by direct nitridation of aluminum metal and classification. The angular AlN are not expected to have high fluidity when mixed with polymers and hence low packing density. Recently, we successfully obtained single-crystalline spherical AlN fillers. Furthermore, polymer composites filled with the spherical AlN showed excellent thermal conductivity (〉8 W/mK) as encapsulants for dissipating the heat generated in electronic devices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1551-2916.2005.00456.x
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  • 3
    Electronic Resource
    Electronic Resource
    Formation and Stability Regions of the High-Temperature Fluorite-Related Phase in the R2O3-Ta2O5 System (R = La, Nd, Sm, Ho, Er, and Yb) (1997)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 80 (1997), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Solid-state reaction and annealing of melts of samples in the R2O3-Ta2O5system (R is a rare-earth element, i.e., La, Nd, Sm, Ho, Er, and Yb) revealed a defect-fluorite phase (F-phase) at high temperatures. The formation region of this F-phase was in the region of ˜70-80 mol% R2O3for small rare-earth ions, such as erbium and ytterbium, but only in the region of ˜80 mol% R2O3at temperatures of 〉1800°C for large rare-earth ions, such as the lanthanum-through-samarium series. This F-phase exhibited disordered cation and anion sublattices, such as (R0.8Ta0.2)(O1.7box0.3). The F-phase decomposed to R2O3 and an ordered phase–R3TaO7 (orthorhombic weberite)–through a eutectic reaction at temperatures in the range of 1500°-1700°C for gadolinium or larger rare-earth ions, whereas the F-phase was stable at 1500°C for the small rare-earth ions (the erbium-through-ytterbium series).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.1997.tb03079.x
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  • 4
    Electronic Resource
    Electronic Resource
    Influence of Powder Particle Size of Slurries on Mechanical Properties of Porous Hydroxyapatite Ceramics (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 284-286 (Apr. 2005), p. 365-368 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The effect of different particle sizes on the flexural strength and microstructure of three different types of hydroxyapatite (HAp) powders was studied. The powder characteristics of laboratory synthesized HAp powder (Lab1 and Lab2) were obtained through a wet milling method, and the median particle size and the specific surface area of powders are different with the dryness period. The median particle sizes of Lab1 and Lab2 are 0.34 µm and 0.74 µm, and the specific surfaceareas of Lab1 and Lab2 are 38.01 m2/g and 19.77 m2/g. The commercial HAp had median particle size of 1.13 µm and specific surface area of 11.62m2/g. The different powder characteristics affected the slip characteristics, and the flexural strength and microstructure of the sintered porous HAp bodies are also different. The optimum value for the minimum viscosity in these present HAp slip with respect to its solid loading and the optimum amount of the deflocculant were investigated. The flexural strengths of the porous HAp ceramics prepared by heating at 1200℃ for 3 hrs in air were 17.59 MPa for Lab1 with a porosity of 60.48％, 10.51 MPa for Lab2 with a porosity of 57.75％, and 3.92 MPa for commercial HAp with a porosity of 79.37％
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/49/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.284-286.365.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    Preparation of Porous Poly(Lactic Acid)/Hydroxyapatite Microspheres Intended for Injectable Bone Substitutes (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 284-286 (Apr. 2005), p. 819-822 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Porous biodegradable microspheres were successfully obtained by an improvement single step and surfactant-free emulsion solvent evaporation method. The organic phase composed of PLA and dichloromethane was stirred in aqueous phase including Ca2+ ions to yield oil in water emulsion. During emulsification, stirring rate was increased so as to produce the W/O/W emulsion that results in microspheres with internal pores. The interface of internal water/oil was stable in W/O/W emulsion, which was explained that the bond between Ca2+ ions and carboxyl group of poly(lactic acid) would be stabilized the internal water/oil interface. Adding PO43- aqueous solution prompted to precipitate low crystallized hydroxyapatite on the external oil/water interface, and the precipitated hydroxyapatite would stabilizied microspheres formation. The resulting microspheres were approximately 100-500 µm with internal spherical pores of 10-200 µm in diameter. The porousbiodegradable microspheres were expected to be utilized as injectable bone substitutes that allow bone ingrowth and bone regeneration
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/49/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.284-286.819.pdf
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  • 6
    Electronic Resource
    Electronic Resource
    Apatite Layer with Serum Protein as a Suitable Scaffold for Growth of Osteoblast-Like Cell (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 284-286 (Apr. 2005), p. 611-614 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Autograft, allograft, and biomaterials had been developed for bone regeneration. Inrecent year, a tissue engineering technique has been paid much attention for next generation implant. A problem of bone tissue engineering to be solved is a development of the substrate that is suitable for cell adhesion, proliferation, and differentiation. A biomimic scaffold for tissue culture was proposed, and then a cell response on the scaffold was estimated. The scaffold composed by a calcium deficient apatite with an adsorbed serum protein was formed on a ceramic hydroxyapatite (HAp) and surface-modified titanium by a soaking in cell-culture medium supplemented with fetal bovine serum. Excellent results on cell proliferation and cell adhesion were obtained only on osteoblast-like cells (MC3T3-E1). An actin filament in narrow filopodium of the spindle-shaped MC3T3-E1 cells on the ceramic HAp had a regular course. On the other hand, ends of the actin filament of the widely spread cells on the apatite layer with serum protein were scattering. It was suggested that the scattering of the actin end showed an existence of fibronectin, and then tight adhesion would be obtained by the many focal adhesion. Accordingly, the effectiveness of the biomimic scaffold containing serum protein on cell growth was confirmed
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/49/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.284-286.611.pdf
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  • 7
    Electronic Resource
    Electronic Resource
    Protein Loading and Solubility of Apatite Hydrogel (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 284-286 (Apr. 2005), p. 63-66 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Protein loading on apatite hydrogel cake and its solubility was studied. A mixture ofdi-sodium hydrogen phosphate dodeca-hydrate and calcium chloride di-hydrate was dissolved in water, and kept at room temperature for 2 weeks in air or N2 atmosphere to make apatite hydrogel. The obtained apatite hydrogel contains carbonate ions, and its carbonate content strongly affect the aggregation of particles. With maturation period, the particle size of apatite hydrogel decreased in air, but increased in N2 atmosphere. The quantity of loaded Cytochrome C in apatite hydrogel formed in air was 0.490 wt%, while that in apatite hydrogel formed under N2 atmosphere was 0.305 wt%. But the quantity of loaded albumin in apatite hydrogel formed in air was less than that in apatite hydrogel formed under N2 atmosphere. The difference may be due to the relationship between isoelectric pointof protein and apatite hydrogel. The apatite hydrogel containing protein was dried for 4 days in air at 40 % of relative humidity to make cakes, and the cakes were immersed in pure water or PBS solution. The dried specimen slowly dissolves in aqueous solution, and the decrease in weight of apatite cake prepared from hydrogel formed in air was larger than that from hydrogel formed under N2 atmosphere compared to the dissolved apatite, the released protein was less, which may be associated with recrystallization of the apatite hydrogel
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/49/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.284-286.63.pdf
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  • 8
    Electronic Resource
    Electronic Resource
    In Vitro Apatite Formation on Surface-Modified Titanium Coatings Prepared by Reactive Plasma Spraying (2005)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 284-286 (Apr. 2005), p. 255-258 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In vitro nucleation of apatite was studied over surface-modified Ti coatings prepared by reactive plasma spraying (RPS). An in-situ surface-modification of Ti particles is conducted by making use of plasma-enhanced reactions between the Ti particles and the reactive gaseous species in the plasma flame during plasma spraying. Surface-modified Ti coatings were deposited on Ti substrates by radio-frequency (rf)-RPS using a thermal plasma of Ar gas containing 1-6% N2 and/or1-6% O2 at an input power of 16 kW. As a means of surface modification, Ti powders impregnated with 0.05-0.2 mol% Ca were also sprayed. Compositional changes in the coatings' surface after soaking in simulated body fluid (SBF) were examined by Fourier transform infrared spectroscopy (FT-IR) and thin film X-ray diffraction (TF-XRD). The Ti coatings prepared with Ar-O2 and Ar-N2-O2 plasma formed apatite after 3 days of soaking in SBF. On the other hand, no compositionalchange was observed in the surface of the Ti coatings sprayed with Ar-N2 plasma, even after 7 days of soaking in SBF. In SBF tests, we observed a retardation of apatite deposition for the Ca-added Ti coatings prepared with Ar-O2 and Ar-N2-O2 plasmas. Analyses by X-ray photoelectron spectroscopy indicated that the Ca impregnated in the RPS-Ti coatings formed a Ca-O compound
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/49/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.284-286.255.pdf
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  • 9
    Electronic Resource
    Electronic Resource
    Synthesis of Apatite Ceramics with Bimodal Pore Structure Using Mechanochemically Prepared Fine Apatite Powder (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 280-283 (Feb. 2007), p. 1571-1574 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Preparation of apatite ceramics with bimodal pore structure was studied. First finehydroxyapatite powder was obtained through mechanochemical method. The particle size of the product was around 0.64 µm. The slurry with the fine apatite powder content of 55-62.5wt% was prepared using defloculant, and foaming reagent. The organic form was immersed into the slurry, dried under vacuum,and heated at 1100°C, 1200°C, 1300°C. Pore size distribution of the product measured by porosimeter showed that small pores of around 1 µm and large pores of 100 µm exist, and SEM observation confirmed. SEM observation showed that the large pores seemed to be interconnected through the openings of several dozens µm in size. The porosity of the products were found to be 48 – 58.5%, and the bending strength of the products obtained by heat-treatment at 1100°C for 3 hours was 5.6 MPa, and that at 1200°C was 10.5 MPa
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/49/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.280-283.1571.pdf
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  • 10
    Electronic Resource
    Electronic Resource
    Advanced Mechanical Properties of Porous Hydroxyapatite Ceramics Prepared Using Hydroxyapatite Slip and its Slurry Synthesis (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 361-363 (Nov. 2007), p. 151-154 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: There is a clinical need for synthetic scaffolds that will promote bone regeneration.Important factors include obtaining an optimal porosity and size of interconnecting macroporeswhilst maintaining scaffold mechanical strength, enabling complete penetration of cells andnutrients throughout the scaffold, preventing the formation of necrotic tissue in the centre of thescaffold. To address this we investigated flexural strength of bimodal porous apatite ceramicsprepared using apatite slurry and its slurry synthesis was studied. Slips with different contents ofHAp (K-HAp and T-HAp) and deflocculant were prepared by milling in a pot mill. The viscosity ofslurries made of commercial T-HAp powder showed a drop after 3 hours’ milling, but the viscosityof slurry with high solid content of k-HAp and 2.0 wt% deflocculant increased with an increase ofmilling time after 2 hours’ milling. The porosity and flexural strength of the porous HAp preparedby heating the foam dipped in K-HAp slip with 2.0 wt% of deflocculant and 0.5wt% of foamingregent heated at 1200℃ were 62.4 % and 14.7 MPa, and those in T-HAp were 59.7 % and 15.2MPa with 1.5 wt% of deflocculant and 0.5wt% of foaming regent heated at 1200℃
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/55/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.361-363.151.pdf
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