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101.
《Ceramics International》2016,42(14):15261-15268
Cellular glass, or foamed glass, has been obtained as a result of the heating (to 700–800 °C) of heavy and strong preforms formed due to the binding properties of the silicate additives. Durability of the preforms reached 6 MPa at the density of 1.8 g/cm3. The main expanding agent in the composition is steam, which can also be a carbon oxidizer and increase the amount of the evolved gases and decrease the density of the foamed glass obtained. As a result of changing the initial composition structure, the density of the obtained foamed glass varied from 0.14 to 0.6 g/cm3, its breaking strength - from 0.6 to 5.0 MPa. and heat conductivity – from 0.045 to 0.15 W/(m·К), respectively. The speed of expansion of the preforms had an extreme character with the induction period typical for topochemical reactions. The obtained cellular materials possessed a distinct crystalline structure. The experiments showed the possibility of obtaining cellular materials with acceptable properties from different types of glass for the solution of environmental tasks. Various technological methods of obtaining cellular material blocks from preforms of various forms were tested to use them for thermal insulation and facing materials. 相似文献
102.
《Ceramics International》2016,42(9):10593-10598
The optimized sintering conditions for a 3.5 wt% magnesia partially stabilized zirconia (Mg-PSZ) refractory were proposed in our recent research. The influence of the sintering temperature on the development of phase composition, microstructure, densification, thermal expansion and mechanical strength was studied in detail by X-ray diffraction (XRD), scanning electron microscope (SEM), He-pycnometer, high temperature dilatometry and three-point bending test. The samples sintered at 1670 °C had the highest bend strength, the maximum densification, the lowest thermal expansion coefficient (CTE), a homogeneous microstructure and a linear change in thermal expansion. 相似文献
103.
《Ceramics International》2016,42(16):18718-18723
Titanium diboride (TiB2) is a ceramic material with high mechanical resistance, chemical stability, and hardness at high temperatures. Sintering this material requires high temperatures and long sintering times. Non-conventional sintering techniques such as spark plasma sintering (SPS) can densify materials considered difficult to sinter. In this study, TiB2–AIN (aluminum nitride) composites were sintered by using the SPS technique at different sintering temperatures (1500 °C, 1600 °C, 1700 °C, 1800 °C, and 1900 °C). x-ray diffraction was used to identify the phases in the composites. mechanical properties such as hardness and indentation fracture toughness was obtained using a vickers indenter. Different toughening mechanisms were identified, and good densification results were obtained using shorter times and lower temperatures than those previously reported. 相似文献
104.
《Ceramics International》2016,42(7):8545-8551
Well-dispersed spherical amorphous alumina nanoparticles with a narrow size distribution were obtained by facile homogeneous precipitation and subsequent calcination. In the synthesis, formamide was used as the precipitant, and mixtures of aluminum sulfate and aluminum nitrate with different molar ratios were used as the aluminum sources. The average size of the amorphous alumina nanoparticles was successfully controlled by adjusting the amount of formamide and the sulfate/nitrate molar ratio. The particle size decreased with increasing amount of formamide and decreasing sulfate/nitrate molar ratio. Dispersed spherical amorphous alumina nanoparticles with average sizes of 23, 34, 45, and 57 nm were prepared using 100 mL formamide at sulfate/nitrate molar ratios of 1:9, 2:8, 3:7, and 4:6, respectively. 相似文献
105.
Mohd Ikram Ramli Abu Bakar Sulong Norhamidi Muhamad Andanastuti Muchtar Mohd Yusuf Zakaria 《Ceramics International》2019,45(9):11648-11653
Composite biomaterials are in high demand in the medical field of today. The combination of bioactive wollastonite (WA) glass ceramic with the biocompatibility of alloy titanium (Ti6Al4V) could be a good candidate for implant applications. The rheological properties of Ti6Al4V/WA feedstock show a pseudoplastic behaviour with low activation energy. The feedstock was successfully injected as a green part with no defects. The green part was solvent debound for 6?h in heptane and thermal debound in an argon environment for 1?h. The brown part was successfully sintered at 1300?°C for 3?h with 5?°C/min heating and cooling rates. The average sintered density was 4.12?g/cm3; which is 97.5% from the theoretical density. The highest Young's modulus obtained was 18.10?GPa; which is in the range of human bone strength. EDX analysis shows that by increasing sintering temperature, the level of oxygen decreased. Cell viability test shown an absorbance increased with days increasing indicated that the cellular were proliferated on the composite Ti6Al4V/WA composite which also proved that the composite was non-toxic. This indicates that the Ti6Al4V/WA composite is suitable for bone implant applications. 相似文献
106.
《Ceramics International》2016,42(8):9844-9850
Materials designed in the high-alumina region of Al2O3–MgO–CaO system have been widely used in many technological fields. However, their further applications are limited by the high sintering temperatures necessary to achieve densification due to the poor sintering ability of calcium hexaluminate (CaAl12O19) and spinel (MgAl2O4). Considering this aspect, the present work investigated the effect of TiO2 addition on the sintering densification and mechanical properties of MgAl2O4–CaAl4O7–CaAl12O19 composite by solid state reaction sintering. The results showed that the CA6 grains presented a more equiaxed morphology instead of platelet structure by incorporating Ti4+ into its structure, which greatly improved the densification after heating at 1600 °C. The flexural strength was greatly enhanced with increasing addition of TiO2 due to the significant decrease in porosity and improvement in uniformity of grain size as well as the absence of microcracks in the presence of Al2TiO5. The increased content of TiO2 also played an active role in toughening this composite attributed to the increase in resistance to crack initiation and propagation. 相似文献
107.
《Intermetallics》2016
Half-Heusler (HH) semiconductor alloys are being widely investigated due to their promising potential for thermoelectric (TE) power generation applications. Sb is an effective doping element for n-type ZrNiSn half-Heuslers alloys. HH thermoelectric materials Hf0.25Zr0.75NiSn1−xSbx (0 ≤ x ≤ 0.03) were synthesized by induction melting combined with plasma activated sintering (PAS) technique. X-ray diffraction concluded that single-phase HH compounds without compositional segregations were obtained. Presence of bended lamellar structures was revealed by the FESEM. Sb doping significantly enhanced the electrical conductivity, power factor and carrier concentration of the alloys. An increase in the carrier mobility was also observed. Consequently, optimum values of 4.36 × 10−3 W/mK2 and 4.7 × 1020 cm−3 were achieved for power factor and carrier concentration, respectively. As a result, a ZT value of 0.83 at 923 K was obtained which is about 67% improvement compared to the un-doped sample. 相似文献
108.
戴孟良 《有色冶金设计与研究》2012,33(1):21-23
介绍韶冶在氧化物料对工厂生产经营和现场环境造成不利影响的条件下,通过设备、工艺两方面的研究,提高氧化物料处理能力,从而增强烧结工艺对原料的适应性,使干精矿含硫降低,烧结机产能大幅度提升,烧结块质量保持较高水平,年创效益约2 500万元。 相似文献
109.
Valdeci Bosco dos SantosJean-Claude M’Peko Valmor Roberto Mastelaro 《Journal of Alloys and Compounds》2012,510(1):60-65
Bi3.25La0.75−xErxTi3O12 and Bi3.25La0.75Ti3−xErxO12−δ ceramics were prepared and studied in this work in terms of dopant-induced phase and microstructure development as well as dielectric response. The results show that introduction of Er3+ tends to reduce the materials’ sintering temperature and average grain size. Moreover, it was noted that in these systems the substitution site of this dopant is controlled by valence state and ionic radii mismatch effects. In particular, even when a nominal substitution of Ti4+ is conceived, here it is found that Er3+ also incorporates at the (Bi,La)3+ sites. These and other interesting concluding remarks from this work, including Er3+ tolerance, were possible only after comparing, especially, the X-ray diffraction results and the intrinsic ferroelectric characteristics extracted from the dielectric measurements. 相似文献
110.
Conventional ceramic and sol-gel auto combustion routes were adopted to develop Mn-Zn ferrite cores. To control high frequency (>500 kHz) losses, zirconia (0.2 wt%) and calcia (0.04 wt%) were added in Mn0.57Zn0.35Fe2.08O4. The results revealed that Mn-Zn ferrite smart cores synthesized by auto combustion process have superior properties than conventionally prepared cores. It is believed that the presence of unique properties such as nanograin microstructure, light weight and short height (thickness) dimensions have played their role to enhance the magnetic impedance of smart core to manifold. Fabricated smart core excellently performed in a test frequency band of 3-15 MHz. 相似文献