The Additives Influence on Heat-Conducting Properties of Aluminium Nitride Circuit Boards

The paper presents the studies on evaluation of the influence of modified additives of Y2O3-, ZrO2- and Li2O3-type on heat-conductive properties of aluminium-nitride ceramics used as circuit boards. Sintering of the studied samples was carried out using AlN powders and the powders of the modifying additives, mixed in the ball mill based on the spark plasma sintering system “SPS”. Density and heat conductivity were measured for the obtained samples. It was ascertained that the most significant level of heat conductivity was obtained when using the additive mixture made of 7 wt. % of Li2O3 and 3wt. % of Y2O3, which reaches the level of 160 W/m·K. In addition, the results of the studies show that the addition of the modified powders leads to a significant increase of density; the additive consisting of 7wt.% of Li2O3 and 3wt.% of Y2O3 produces the greatest effect.