Preparation and characterization of composite Nano powder Al2O3-Cr2O3

Dissertant

Mehatlaf, Auday Abid

Thesis advisor

Chyad, Fadil A.
Ali, Abd al-Rahim K. Abid

University

University of Technology

Faculty

-

Department

Department of Materials Engineering

University Country

Iraq

Degree

Master

Degree Date

2012

English Abstract

Alumina one of the ceramic materials has high hardness, chromia has a stability in corrosive media.

These properties promote to prepare ceramic- ceramic nano composite from them.

In this study, nano composite powder from alumina/chromia at (2,6,10,15,20 wt%) chromia, was prepared using modified sol-gel technique.

Solution with 0.5 M from each aluminum nitrates and chromium nitrates were used with 50/50 ratio of ethanol/water as solvent solution at room temperature.

Furthermore, glucose with 7 % was used as surfactant material.

Calcination temperature 600cc was used after getting the gel.

Several tests such as thermogravimetry-differential thermal analysis, energy-dispersive X-ray spectroscopy, X-ray diffraction, transmission electron microscope, and scanning electron microscope for the prepared calcined powder.

Entering at 1250cc,1450cc and 1650cc has been done for one hour to the formed samples.

After sintering, physical properties, such as apparent density, porosity and water absorption, have been measured.

Microstructure examination after sintering is revealed by scanning electron microscope, light optical microscope, X-ray diffraction and energy-dispersive X-ray spectroscopy has also been studied.

Vickers micro hardness and Brazilian test have also been conducted as mechanical properties for all samples.

It is clear that the average particle size for composite with 15 wt% chromia sample is 4.5nm by using transmission electron microscope technique after calcinations at 600cc for two hours.

After sintering at 1650cc for one hour, the composite specimen with 20% chromia has 4.2 g/cm3 apparent density, apparent porosity was 10%.

The maximum Vickers hardness for prepared composite with 15 % chromia sample at 1650cc for one hour is 1473 MPa.

Whereas, the highest tensile strength for Brazilian test is 19.7 MPa for same sample and at same conditions.

Main Subjects

Engineering & Technology Sciences (Multidisciplinary)

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-418883