The effects of silica addition on the structural, electrical and mechanical characteristics of MgAl2O4 spinel ceramic phase

Nadher I Mohammed

doi:10.30723/ijp.v16i37.87

Abstract

The ceramic compound Mg1-xSixAl2O4 (x= 0, 0.1, 0.2, 0.3, 0.4) was prepared from nano powder of Al2O3 and MgO doped with Nano powder of SiO2 at different molar ratios. The specimens were prepared by standard chemical solid reaction technique and sintered at 1450 oC. Structure of the specimens was analyzed by using X-ray diffraction (XRD). The X-ray patterns of the specimens showed the formation of pure simple cubic spinel structure MgAl2O4 phase with space group of ̅ . The average grain size and surface topology were studied by atomic force microscopy. The results showed that the average grain size was about 73-90 nm. The DC electrical properties of the specimen were measured. The apparent density was found to increase and the porosity and water absorption were found to decrease with increase of Si addition. Mechanical properties were characterized by Vicker’s micro hardness and Brazilian fracture test to measure the fracture toughness of the samples. The micro hardness decreased with Si addition increase. Fracture toughness increased with the increase in Si addition.

Highlights

Nano structured magnesium aluminate (MgAl2O4) spinel is one of the most interesting refractory oxides of vast technological importance as a structural ceramic material
There are some spinel's systems which are occupied by both trivalent the tetrahedral positions and divalent ions known as the inverse spinel structure [8]
X-ray diffraction shows that all the specimens are of MgAl2O4 single phase

Summary

Introduction

Nano structured magnesium aluminate (MgAl2O4) spinel is one of the most interesting refractory oxides of vast technological importance as a structural ceramic material. The mechanism of polarization in spinel aluminates is governed by the arrangement of ions in different sites [4]. A series of magnesium aluminate (MgAl2O4) doped with silica at different molar ratios was obtained.

Results

Conclusion