An Investigation on the Synthesis of MgO-ZrB2 Nanocomposite by Mechanochemical Process

In the present study, MgO-ZrB2 nanocomposite was produced by the mechanochemical process of Mg, ZrO2 and H3BO3 stoichiometry mixture. For this purpose, the powder mixture was mechanically milled for different milling times at 350 and 450 rpm in Ar atmosphere. The ball to powder ratio was 10:1. Also, to control the process and prevent the agglomeration and sticking of powders, process control agent was employed. The results of X-ray diffraction, Differential scanning calorimetry (DSC) and scanning electron microscopy showed that lower milling speed (350 rpm) leads to gradually progress reaction in contrast with higher milling speed (450 rpm) which cause to the combustion reaction. Also when the milling speed was 450 rpm the Mg2Zr5O12 was created which confirms combustion reaction has taken place. The average grain size of MgO and ZrB2after 15 h of milling at 450 rpm, were 90 and 47 nm, respectively. For determination of reaction activation energy, DSC was done for the sample milled for 25 h at 350 rpm with heating rates of 20, 30 and 40 oC/min in Ar atmosphere. The estimated value for the reaction activation energy of reaction was determined about 179.5 kJ/mol.

An Investigation on the Synthesis of MgO-ZrB2 Nanocomposite by Mechanochemical Process Keywords:

MgO nanocomposite , Mechanochemical reaction , DSC analysis , Activation energy