Solid Solution Effects on the Thermal Properties in the MgAl_2O_4-MgGa_2O_4 System

摘要

Solid solution effects on thermal conductivity within the MgO-Al_2O_3-Ga_2O_3 system were studied. Samples with systematically varied additions of MgGa_2O_4-MgAl_2O_4 were prepared and the laser flash technique was used to determine thermal diffusivity at temperatures between 200℃ and 1300℃. Heat capacity as a function of temperature from room temperature to 800℃ was also determined using differential scanning calorimetry (DSC). Solid solution in the MgAl_2O_4-MgGa_2O_4 system decreases the thermal conductivity up to 1000℃. At 200℃ thermal conductivity decreased 24% with a 5 mol% addition of MgGa_2O_4 to the system. At 1000℃, the thermal conductivity decreased 13% with a 5 mol% addition. Steady-state calculations showed a 12.5% decrease in heat flux with 5 mol% MgGa_2O_4 considered across a 12 inch thickness.