Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : ZrO


Effect of Sintering Process and Starch Amount on the Porosity and Permeability of Al2O3-ZrO2 High Porous Oil Filters

S.A. Ajeel; N.E. Abdul Latiff; A.A. Al-Attar

Engineering and Technology Journal, 2017, Volume 35, Issue 9, Pages 887-893

Alumina-Zirconia is prepared for oil filter. Oil filters are used to separate oil derivatives from each other using separation principles depending on the size of the holes. These filters work on the principle of separation depending on the density and viscosity of liquid or on the difference in impurity crystals size. This work involves preparation of filters from Alumina-Zirconia powder materials by a hybrid freeze casting and space-holder method. These filters have excellent properties such as stability at high temperature, excellent corrosion resistance; withstand static stresses, and other unique thermal properties. Alumina-Zirconia powder is mixed with different amounts of (zero, 15, 25, and 35 vol. %) of starch powder. Powder mixture has been blending with water using an electric mixer to obtain homogeneous slurry. Solid: liquid ratio of slurry of 30:70 is poured in a cylindrical metal molds and freezed by liquid nitrogen chamber. The solidified material was heat treated at 300 °C for 60 min then sintered at 1550 °C, 1600 °C and 1700 °C under vacuum for 120 min. Hot samples were cooled inside furnace until room temperature. The sintered materials were examined to show the effect of starch adding and sintering process on the porous structure and permeability ratio of the fluid using Archimedes method and SEM image analyzed by J-image program. Best permeability and homogeneous porous structure are obtained at 1600 °C sintering temperature with 24 vol. % of starch powder.

Numerically and Theoretically Studying of the Upper Composite Complete Prosthetic Denture

Sihama I. Salih; Jawad K. Oleiwi; Qahtan A. Hamad

Engineering and Technology Journal, 2015, Volume 33, Issue 5, Pages 1023-1037

The current study focused on the manufacturing and development properties of upper prosthesis complete denture from composite materials with the basis cold cured resin of poly methyl methacrylate as new fluid resin and reinforced materials by two different types of particles (nano-hydroxyapatite (nHA), micro zirconia (ZrO2)), that added with different volume fractions of (1%, 2% and 3%), and the different types of woven fibers (Glass fiber, Kevlar fiber), it were added with a fixed volume fraction of (5%) to PMMA composites.Specimens’ consist of a six groups where prepared by using (Hand Lay-Up) method from the composites materials and hybrid laminated composites materials. This research includes theoretical and numerical studies by using finite element method to confirming the experimental results of the effect of selected volume fractions of theseparticles and fibers on the (total deformation distribution, equivalent elastic strain and equivalent Von Mises stress) of the composite prosthetic dentures.
The theoretical part included calculations the values of theoretical safety factor and Poisson's ratio. While the numerical part based on finite element method (F.E.M), which was performed by using program (ANSYS-15) to analyze the prepared of denture composite materials and evaluate its characteristics which represent total deformation distribution, equivalent stress and equivalent elastic strain. This was performed by obtaining twenty one models for the PMMA composite dental prostheses which were treated as three dimension structure. The numerical results of the F.E.A showed coincided with some of the experimental results.

Properties of Nano Thin Film Composed of Nan Crystalline Zro2 Prepared by (SOL - GEL) Method

Kassim Mohammed Sahan; Aqel Mashot Jafar

Engineering and Technology Journal, 2014, Volume 32, Issue 1, Pages 23-32

Nano-crystalline ZrO2 was prepared by sol-gel method and deposited on glass substrate by dip-coating technique method in the room temperature. ZrOCl2 was dissolved in a solvent mixture composed of H2O2 and ammonia. The dissolving reaction produced a colorless, transparent peroxozirconium complex solution. The mean nanocrystalline size was about 7.55 nm. The zirconium film thus obtained was transparent 90% with 5.03 eV band gap. Atomic force microscopy (AFM), X-ray diffraction and (UV-Vis) used to determine the properties of the thin film. The as-deposited thin film was of high purity of ZrO2 and good adhesion to the substrate. The annealing was caused crystallization of tetragonal and monoclinic phase present in the zirconia at 550°C in air. The film showed very flat surfaces consisting of nanoparticles with particle size of ranging (2-10 nm).

Synthesize Nano ZnO-ZrO2 Composite by Combustion Method and Studying their Dielectric Properties

Fadhil A.Chyad

Engineering and Technology Journal, 2012, Volume 30, Issue 8, Pages 1342-1350

Combustion method had been used to prepare a composite material from doping
ZnO by 10 mol% ZrO2 . XRD showed a good crystalline powder comparing with
ASTM cards. Dielectric properties such dielectric strength, dielectric constant,
dielectric loss and tangent loss have been measured .All the dielectric properties
have decreased as the frequency increasing .
The particle size has great effect on the dielectric properties of the composite
which decreased as the particle size increased .