Study of Sintering of Oxide Ceramics at Constant Rate of Heating and by means of Rate-Controlled Sintering Method

2006 ◽  
pp. 161-166 ◽  
Author(s):  
Karel Maca ◽  
Hynek Hadraba ◽  
Jaroslav Cihlar
Keyword(s):  
Oxide Ceramics ◽  
Constant Rate ◽  
Rate Controlled ◽  
Rate Of Heating ◽  
Sintering Method

scholarly journals Microstructure evolution during pressureless sintering of bulk oxide ceramics

2009 ◽  
Vol 3 (1-2) ◽  
pp. 13-17 ◽  
Author(s):  
Karel Maca
Keyword(s):  
Grain Size ◽  
Ceramic Materials ◽  
Oxide Ceramic ◽  
Oxide Ceramics ◽  
Final Density ◽  
Constant Rate ◽  
Final Microstructure ◽  
Injection Molded ◽  
Rate Controlled ◽  
Rate Of Heating

The author's experience concerning the influence of the choice of different pressureless heating schedules on the final microstructure of oxide ceramic materials is summarized in the paper. Alumina, ceria, strontium titanate, as well as tetragonal (3 mol% Y2O3) and cubic (8 mol% Y2O3) zirconia were cold isostatically pressed or injection molded and pressureless sintered with different heating schedules - namely with Constant-Rate of Heating with different dwell temperatures (CRH), with Rate-Controlled Sintering (RCS) and with Two-Step Sintering (TSS). It was examined whether some of these three sintering schedules, with the same final density achieved, can lead to a decrease of the grain size of sintered ceramics. The results showed that only TSS (and only for selected materials) brought significant decrease of the grain size. .

scholarly journals Time-dependent behaviour of sand with different fine contents under oedometric loading

2019 ◽  
Vol 56 (1) ◽  
pp. 102-115 ◽  
Author(s):  
Friedrich Levin ◽  
Stefan Vogt ◽  
Roberto Cudmani
Keyword(s):  
Strain Rate ◽  
Creep Behaviour ◽  
Silty Sand ◽  
Granular Soils ◽  
Rate Dependency ◽  
Viscous Effects ◽  
Fine Content ◽  
Constant Rate ◽  
Rate Controlled ◽  
Strain Rate Dependency

To characterize the effects of creep, strain rate, and relaxation in granular soils, different sands have been studied under oedometric loading. The tests were analysed in the framework of the isotache concept. The results show increasing creep rates with increasing vertical stresses and a strong reduction of the creep rate upon unloading. A lower void ratio leads to less creep. Evaluation of the ratio Cα/Cc, where Cα is the creep coefficient and Cc is the compression index, demonstrates considerable deviation from a constant soil-specific value for the sands. With increasing fine content, however, a constant soil-specific ratio has been found for a silty sand. In strain rate–controlled tests, a sand with low and a sand with significant content of nonplastic fines were compared. Constant rate of strain tests displayed practically no strain rate dependency for the sand with little fines and a well visible strain rate dependency for the very silty sand. Tests with stepwise change of strain rate showed non-isotache behaviour for the sand with little fines and isotache behaviour for the other. Stress-relaxation tests displayed an isochronous behaviour. The analysis of the three viscous effects in sands showed they cannot altogether be mathematically described in the framework of the isotache concept. A new compression model for the creep behaviour of sands is presented.

Sintering and Mechanical Properties of Dense Hydroxyapatite Nanocomposites

2010 ◽  
Vol 123-125 ◽  
pp. 771-774 ◽  
Author(s):  
Chanoknan Monthien ◽  
Kanjana Silikulrat ◽  
Gobwute Rujijanagul ◽  
Tawee Tunkasiri ◽  
Sittiporn Punyanitya ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Biological Properties ◽  
Hard Tissue ◽  
Engineering Applications ◽  
Sintering Additive ◽  
Rate Controlled ◽  
Hard Tissue Engineering ◽  
Sintering Method

During recent years, there have been efforts in developing nanocrystalline bioceramics, to enhance their mechanical and biological properties for use in hard tissue engineering applications. In this work, we study the effects of some sintering additive nanopowders dopants on the properties of the sintered HA structures. Calculated quantities of silica nanopowders are incorporate as dopants into dried HA nanopowder. The mixing powders are uniaxially compacted and then sintered at 1200°C by rate-controlled sintering method in air. Compositional, microstructural, morphological and mechanical characterizations are carried out on sintered HA samples.

scholarly journals Kinetics of Sintering at a Constant Rate of Heating

1971 ◽  
Vol 79 (914) ◽  
pp. 370-376 ◽  
Author(s):  
Yusuke MORIYOSHI ◽  
Wazo KOMATSU
Keyword(s):  
Constant Rate ◽  
Rate Of Heating ◽  
Kinetics Of

Dielectric Properties of Barium Titanate Ceramics with Nano-Sized Domain

2010 ◽  
Vol 445 ◽  
pp. 27-30 ◽  
Author(s):  
Yoichi Kigoshi ◽  
Saki Hatta ◽  
Takashi Teranishi ◽  
Takuya Hoshina ◽  
Hiroaki Takeda ◽  
...  
Keyword(s):  
Grain Size ◽  
Barium Titanate ◽  
Dipole Polarizability ◽  
Ionic Polarizability ◽  
Grain Sizes ◽  
Conventional Sintering ◽  
Rate Controlled ◽  
Titanate Ceramics ◽  
Sintering Method ◽  
Domain Width

Barium titanate (BaTiO3) ceramics with various grain sizes from 0.7 to 13 μm on average were prepared by a conventional sintering method, a two-step sintering method and a rate controlled two-step sintering method. The permittivity of the ceramics was increased with decreasing grain size to 1.1 μm on average. However, the permittivity of the ceramics was decreased when the grain size was below 1 μm. The field emission scanning electron microscope (FE-SEM) observations revealed that the 90º domain width decreased with decreasing the grain size. By ultrawide range dielectric spectra from kHz to THz range of the BaTiO3 ceramics, the domain contribution to the permittivity was investigated. For the BaTiO3 ceramics with grain sizes over 1 μm, the dipole polarizability and the ionic polarizability were enhanced by high domain-wall density. In contrast, for the BaTiO3 ceramics with grain sizes below 1 μm, these polarizabilities were weakened.

scholarly journals Oxidation of Nb-19at%Al Alloy in Oxygen During a Constant Rate of Heating up to 1000^|^deg;C

1994 ◽  
Vol 43 (7) ◽  
pp. 364-370
Author(s):  
Mieko Okamoto ◽  
Isao Tomizuka ◽  
Akimitsu Miyazaki
Keyword(s):  
Al Alloy ◽  
Constant Rate ◽  
Rate Of Heating ◽  
Heating Up

Isothermal and nonisothermal sintering kinetics of glass-filled ceramics

1992 ◽  
Vol 7 (12) ◽  
pp. 3342-3347 ◽  
Author(s):  
Jau-Ho Jean ◽  
Tapan K. Gupta
Keyword(s):  
Experimental Data ◽  
Viscous Flow ◽  
Linear Shrinkage ◽  
Sintering Kinetics ◽  
Constant Rate ◽  
Rate Of Heating ◽  
Powder Compacts ◽  
Kinetics Of

Isothermal and nonisothermal sintering behaviors of glass-filled ceramics are compared in this paper. Equations developed to describe the kinetics of shrinkage for both techniques can be readily used to interpret the experimental data. It is shown that the kinetics of linear shrinkage of powder compacts during isothermal and nonisothermal constant rate of heating are consistent and can be described by the viscous flow of glass.

Sign in / Sign up

Export Citation Format

Share Document