scholarly journals Synthesis of zirconia colloidal dispersions by forced hydrolysis

2006 ◽  
Vol 71 (6) ◽  
pp. 613-619 ◽  
Author(s):  
Jelena Markovic ◽  
Slobodan Milonjic

Different zirconia colloidal dispersions (sols) were prepared from zirconyl oxynitrate and zirconyl oxychloride solutions by forced hydrolysis. Vigorously stirred acidic solutions of these salts were refluxed at 102 oC for 24 h. Characterization of the obtained sols (pH, solid phase content crystal structure) was performed by potentiometric, XRD, TGA/DTA and SEM measurements. The prepared sols contained almost spherical monoclinic hydrated zirconia particles 7-10 nm in diameter.

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1563 ◽  
Author(s):  
Hang Zhang ◽  
Shuhai Liu ◽  
Huaping Xiao ◽  
Xun Zhang

Ceramic materials possessing the properties of high-strength and rigidity are widely used in industry. The shell nacre has a layered structure containing both macroscopic and microscopic levels and is equipped with superior qualities regarding hardness and strength. Therefore, the ceramic composites with a nacre-like layered structure have the potential to be utilized as sliding bearings employed in the harsh conditions of wells. For the purpose of this paper, a porous Al2O3 ceramics skeleton with nanometer powder is prepared using the freeze-casting method. Then the porous ceramic skeleton is filled with polymer polymethyl methacrylate (PMMA) through mass polymerization to produce a bionic Al2O3/PMMA composite with a lamellar structure. The properties of the prepared composite are determined by the analysis of micro-hardness, fracture toughness, friction coefficient, wear scar diameter, and the morphology of the worn surface. Consequent results indicate that elevation in the A12O3 powder, which acts as the initial solid phase content, prompts the ceramic slurry to exhibit an increase in viscosity and a gradual decrease in the pore size of the ceramic skeleton. The prepared layered Al2O3/PMMA composite possesses high fracture toughness, which closely resembles that of Al, is approximately four times that of the matrix of the Al2O3 ceramics and 16 times that of the PMMA. Three kinds of composites containing different solid phase content are subjected to testing involving lubrication by water-based drilling fluid to determine the friction coefficient of each. The results indicate that an increased load leads to a decreased friction coefficient while the impact of speed is not evident. Under dry conditions, the friction coefficient of three different composites tested, declines with elevated load and speed. With the use of water-based drilling fluid as lubrication, the wear scar diameter increases at higher speed, while dry conditions denote increased load. Abrasive wear is determined to be the principal form of erosion of layered Al2O3/PMMA composites.


2004 ◽  
Vol 37 (6) ◽  
pp. 923-928 ◽  
Author(s):  
U. Kertzscher ◽  
G. Dimitroff ◽  
M. Binsteiner ◽  
K. Affeld ◽  
L. Goubergrits ◽  
...  

2012 ◽  
Vol 433-440 ◽  
pp. 1391-1396
Author(s):  
Xiao Chen Chen ◽  
Jing Guang Liu ◽  
Guo Hong Xie

Hydraulic water separator can realize the automatic control function by the use of pump-control speed electro-hydraulic servo control system. It can keep the centrifuge adapting to the changes of the water parameters fully with the real-time date collection of centrifugal speed according to different parameters including the density, viscosity, solid-phase content and particle size. It can achieve the best effect by the assurance that the centrifuge is always in the best condition.


1978 ◽  
Vol 80 (5) ◽  
pp. 180-186 ◽  
Author(s):  
J. C. Vanden Enden ◽  
A. J. Haighton ◽  
K. van Putte ◽  
L. F. Vermaas ◽  
D. Waddington

2000 ◽  
Author(s):  
J. Horský ◽  
M. Raudenský ◽  
P. Kotrbácek ◽  
Ampere A. Tseng

Abstract Semisolid or mushy-state processing permits a material to partially solidify before shape making operations. The understanding of material behavior in the mushy state is critical for better control of various semisolid processes. The aim of the present study is to experimentally quantify the deformation behaviours of steel in mushy states. Semisolid specimens under indentation and upsetting deformation were evaluated at various forming speeds and mushy states. The temperature of specimens was carefully controlled to correlate the solid phase content. It has been found that the deformation resistance of steel in a mushy state was dependent on the deformation rate and the solid phase percentage. The relaxation of steel and stress reduction at mushy states were also observed and discussed.


1991 ◽  
Vol 5 (6) ◽  
pp. 908-913 ◽  
Author(s):  
Walther Batsberg Pedersen ◽  
Asger Baltzer Hansen ◽  
Elfinn Larsen ◽  
Anne B. Nielsen ◽  
Hans Petter Roenningsen

1997 ◽  
Vol 12 (12) ◽  
pp. 3286-3292 ◽  
Author(s):  
Luis A. Pérez-Maqueda ◽  
Egon Matijević

A method for the preparation of nanosized zirconium (hydrous) oxide particles of narrow size distribution is described. The procedure yields stable dispersions at low temperatures and short reaction times in the absence of surfactants, using inorganic zirconium salts. Crystal structure, particle size distribution, electrokinetic properties, stability, and thermal behavior of the prepared particles were investigated. Colloidal dispersions were treated with ultrasound to study their effect on the crystal structure of the calcined samples.


2019 ◽  
pp. 59-67
Author(s):  
Ramiz A. Gasumov ◽  
Sergey V. Kostyukov

The article is devoted to the results of laboratory studies of blocking compounds with a condensable solid phase based on calcium. The features of such systems have been revealed and their positive characteristics have been determined. It made it possible to conclude that such systems compounds are promising as blocking compounds for usage in wells with complicated mining and geological conditions (abnormally low reservoir pressures, in reservoirs with complex mineralogical and chemical composition with a high clay content fractions, with a highly fractured bottomhole formation zone, etc.).Based on the data obtained, we have developed blocking compounds with a condensable solid phase (the patent RU 2543003 and the patent RU 2651687), which have high blocking properties (withstand pressure drop up to 20 MPa) and ensure the preservation of reservoir properties (permeability recovery coefficient is more than 95 %) and inhibition of clay minerals swelling. In addition, as a result of studies we have found that for the blocking of productive deposits with a nonuniform permeability (for reservoirs with an average permeability about 1 Darcy) the usage of compounds with a close to stoichiometric ratio of precipitating components with a condensed solid phase content about 11 wt. % is optimal.


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