Temperature Range

In the present work, 3 mol% Yttria-stabilized tetragonal zirconia (Y-TZP) composite containing 25 wt.% of zirconium diboride (ZrB2) was prepared via pressureless sintering method in an inert atmosphere over the temperature range of 1350-1550°C for one hour. The effect of zirconium diboride content in the zirconia matrix, as well as the sintering temperature on densification, phase stability and electrical properties of sintered samples have been studied. The results revealed that there was a significant increased in electrical conductivity of sintered samples when 25 wt.% of ZrB2 is incorporated into Y-TZP matrix.

http://www.scientific.net/MSF.694.304

In this study, in order to detect probable trends and effects of climatic extreme events of precipitation and temperature as well as maximum relative humidity, dew point temperature, sunshine hours, and wind speed, 12 stations on the northern and southern ...

Deep eutectic solvents (DESs) are considered nowadays as green ionic liquid (IL) analogues. Despite their relatively short period of introduction as a special class of ILs, they have been under an increasing emphasis by the scientific community due to their favorable properties. In the present study, a glucose based DES of choline chloride (2-hydroxyethyl-trimethylammonium chloride) with the monosaccharide sugar d-glucose anhydrous was synthesized at different molar ratios. The physical properties of density, viscosity, surface tension, refractive index, and pH were measured and analyzed as function of temperature in the practical temperature range of 298.15-358.15 K. The analysis of these physical properties revealed that these novel DESs have the potential to be utilized for several possible industrial applications involving processing and separation of food constituents, pharmaceutical applications, as well as mediums for chemical reactions. © 2012 Elsevier B.V.

http://ac.els-cdn.com/S0167732212004382/1-s2.0-S0167732212004382-main.pdf?_tid=b5a468c2-0ca1-11e4-b32b-00000aacb35d&acdnat=1405485120_3986b537c7d953e133b7117c8d72dee4 
http://www.sciencedirect.com/science/article/pii/S0167732212004382

In the present work, the sintering behaviour of HA particles prepared via the wet precipitation method (HAp) and wet mechanochemical technique (HAwm) was investigated. The sintering behaviour of a commercial HA powder (HAc) was also studied for comparison purpose. All the three powders were characterised in terms of particle size, Ca/P ratio and crystal size. Green samples were prepared and sintered in air at temperatures ranging from 1000 °C to 1400 °C. The sintered bodies were studied in terms of the phase stability, relative density, Young's modulus, Vickers hardness, fracture toughness and grain size. The results indicated that HAwm samples suffered phase decomposition while the HAp and HAc sintered samples showed no phase disruption throughout the temperature range employed. The HAp samples exhibited the overall best densification and properties when compared to the HAc and HAwm samples. Furthermore, the results showed that mechanical properties of sintered samples were governed by both the bulk density and the grain size.

http://www.sciencedirect.com/science/article/pii/S0272884212005123

Predicting densities of nonconventional solvents like deep eutectic solvents (DESs) as a function of temperature is of considerable importance in the development and design of new processes utilizing these solvents. Because of the nature of bonding existing between the salt and the hydrogen bond donor, conventional methods result in very large deviations. In this study, the density of DESs based on three different salts was estimated using empirical method. Nine different salts:hydrogen bond donor combinations were selected to test this method. The densities of all DESs were measured at a temperature range (298.15–368.1 K). The critical properties of salt and hydrogen bond donor were estimated using the Modified Lydersen–Joback–Reid method, while that of the mixture were calculated using Lee–Kesler equation. The Rackett equation modified by Spencer and Danner was employed to predict the DES density. The values of measured and predicted densities were compared and the average of absolute relative error percentage (ARPE) for all DESs was found to be 1.9%. The effect of salt to HBD molar ratio on ARPE in predicted DESs densities was also investigated.▶ An empirical method is introduced to predict deep eutectic solvents densities as function of temperature. ▶ The correlation showed high prediction quality for all tested DESs. ▶ The density of the DESs lies between the densities of the corresponding salt and HBD used in their synthesis. ▶ The relative difference of densities between the DES and the HBD directly affects the quality of density prediction.

Dense manganese-doped biphasic calcium phosphate (Mn-BCP) ceramics were fabricated via uniaxial pressing using the sol-gel derived powders. The compacted discs were sintered in ambient atmosphere with temperatures ranging from 800C to 1400C. Manganese (Mn) level was varied in the range of 0.6, 1.9, 4.3, and 11.9mol%, and its effect on physical and mechanical properties of the dense samples were investigated. All dense samples have been proved to show HA and -TCP phases only. Mn doping has shifted the onset of the sintering temperature of the BCP, leading to the improved densification of BCP ceramics. The relative density also increased with sintering temperature. Considerable grain growth has been observed for Mn-doped BCP samples when compared to the undoped BCP. Furthermore, 11.9mol% Mn-doped BCP dense samples showed the maximum hardness of 6.66GPa compared to 2.89GPa for the undoped BCP. The incorporation of Mn was also found to be beneficial in enhancing the fracture toughness of BCP throughout the temperature range employed. This study has shown that Mn doping was effective in improving the sintering properties of BCP without affecting the phase stability.

http://www.tandfonline.com/doi/abs/10.1080/10426914.2011.557285#.Uf79787vPgg

Titanium dioxide (TiO2) nanowires were grown on Ti - 6wt% Al - 4wt% V (Ti64) particles by thermal oxidation. To investigate the effect of stress on nanowire growth, the particles were milled in a planetary ball mill prior to the thermal oxidation. Thermal oxidation of the Ti64 particles was carried out in a horizontal tube furnace in a controlled oxygen atmosphere in the temperature range of 700-900 °C. The oxygen concentration was varied from 20 ppm to 80 ppm in Ar atmosphere. Nanostructures were characterized by high resolution field emission scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. TiO2 nanowires grew on the surface of Ti64 particles and exhibited a square/rectangular cross sectional shape with thicknesses of 20-40 nm and lengths of 2-3 μm. Residual stress was found to play a significant role in nanowire growth. This was confirmed by growing TiO2 nanowires on Ti64 alloy sheet with an induced stress gradient along its length. An improvement in nanowire coverage was observed in regions of high residual stress. A stress-induced growth mechanism is suggested to explain the confinement of nanowire growth to one dimension during thermal oxidation.

http://www.sciencedirect.com/science/article/pii/S0272884213001181

"The sinterability of calcined synthesized HA (700°C to 1000°C) was investigated over the temperature range of 1050°C to 1350°C in terms of phase stability, bulk density, Young's modulus and Vickers hardness. Calcination has resulted in higher crystallinity of the starting synthesized HA powder. Decomposition of HA phase to form secondary phases was not observed in the present work for the calcined powders. The results also indicated that calcination of the HA powder prior to sintering has negligible effect on the sinterability of the HA compacts (up to 900°C). Further treatment at 1000°C was found to be detrimental to the properties of sintered HA.


http://link.springer.com/chapter/10.1007/978-3-642-21729-6_18

Predicting densities of nonconventional solvents like deep eutectic solvents (DESs) as a function of temperature is of considerable importance in the development and design of new processes utilizing these solvents. Because of the nature of bonding existing between the salt and the hydrogen bond donor, conventional methods result in very large deviations. In this study, the density of DESs based on three different salts was estimated using empirical method. Nine different salts:hydrogen bond donor combinations were selected to test this method. The densities of all DESs were measured at a temperature range (298.15-368.1 K). The critical properties of salt and hydrogen bond donor were estimated using the Modified Lydersen-Joback-Reid method, while that of the mixture were calculated using Lee-Kesler equation. The Rackett equation modified by Spencer and Danner was employed to predict the DES density. The values of measured and predicted densities were compared and the average of absolute relative error percentage (ARPE) for all DESs was found to be 1.9%. The effect of salt to HBD molar ratio on ARPE in predicted DESs densities was also investigated. © 2011 Elsevier B.V. All rights reserved.

http://ac.els-cdn.com/S0040603111000050/1-s2.0-S0040603111000050-main.pdf?_tid=1ca138a2-0ca2-11e4-ba38-00000aacb360&acdnat=1405485293_095c201a671a034bbd3ed6030fed54ca 
http://www.sciencedirect.com/science/article/pii/S0040603111000050

"The sintering behavior of synthesized nanocrystalline hydroxyapatite (HA) powder was investigated in terms of phase stability and mechanical properties. A wet chemical precipitation method was successfully employed to synthesize a high purity and single phase HA powder. After shaping, HA powder compacts have been sintered over the temperature range of 1000 degrees C to 1300 degrees C. Two different sintering holding times of 1 minute and 120 minutes were investigated. The results revealed that the 1 minute holding time profile was effective in suppressing grain growth and producing a HA body with improved densification. Additionally, higher mechanical properties such as Young's modulus of 119 GPa, high fracture toughness of 1.41 MPa.m(1/2) and hardness of 9.5 GPa were obtained for this sample as compared to HA bodies when sintered using the 120 minutes holding time. The study revealed for the first time that HA could be sintered using a 1 minute holding time without compromising on HA phase stability and mechanical properties.

http://www.ingentaconnect.com/content/ben/cnano/2011/00000007/00000006/art00004

The sintering behavior of synthesized nanocrystalline hydroxyapatite (HA) powder was investigated in terms of phase stability and mechanical properties. A wet chemical precipitation method was successfully employed to synthesize a high purity and single phase HA powder. After shaping, HA powder compacts have been sintered over the temperature range of 1000°C to 1300°C. Two different sintering holding times of 1 minute and 120 minutes were investigated. The results revealed that the 1 minute holding time profile was effective in suppressing grain growth and producing a HA body with improved densification. Additionally, higher mechanical properties such as Young's modulus of 119 GPa, high fracture toughness of 1.41 MPa.m 1/2 and hardness of 9.5 GPa were obtained for this sample as compared to HA bodies when sintered using the 120 minutes holding time. The study revealed for the first time that HA could be sintered using a 1 minute holding time without compromising on HA phase stability and mechanical properties.

http://www.ingentaconnect.com/content/ben/cnano/2011/00000007/00000006/art00004

The sinterability of hydroxyapatite (HA) powder synthesized through a novel wet chemical method (HAp) and a wet mechanochemical method (HAwm) was investigated over a temperature range of 1000°C to 1400°C in terms of phase stability, bulk density, hardness and fracture toughness. The results indicated that the sinterability of HAp powder were significantly better than HAwm powder. Moreover, the XRD traces of HAwm sintered samples showed signs of decomposition into TTCP when sintered at 1300°C and above. Densification of ∼98% of theoretical density was attained by HAp compacts at 1100°C while the HAwm compacts exhibited only ∼96% of theoretical density even at 1350°C with no significant increase of density at 1400°C. The Vickers hardness of HAp showed increasing trend for temperature range of 1000°C to 1100°C with the compacts attaining HV of ∼7 GPa at 1100°C. Subsequently, the hardness decreased with increasing sintering temperature though the value does not dropped below ∼5 GPa. Similarly, Hawm compacts showed an increasing trend from 1000°C to 1300°C with the largest HV attained was ∼4.57 GPa. Further increased in sintering temperature resulted in the decreased of Vicker's hardness. Moreover, the HAp samples reached a maximum fracture toughness of ∼0.9 MPam1/2 at 1050°C while the HAwm attained maximum KIc of only ∼0.7 MPam1/2 at 1300°C.

http://www.scientific.net/AMR.264-265.1538