In-situ synthesis of co-continuous aluminum-aluminum nitride composites by arc plasma induced accelerated displacement reaction

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>We investigate in-situ formation of co-continuous aluminum (Al)-aluminum nitride (AlN) composites with attractive mechanical and thermal properties by newly developed arc plasma-induced accelerated displacement reaction (APADR). The core innovation of the process is that it combines a simple pressureless infiltration with a thermodynamically favorable displacement reaction of silicon nitride (Si<SUB>3</SUB>N<SUB>4</SUB>) and molten Al under arc-plasma induced ultra-high temperature. The fast volume displacement nitridation via APADR resulted from improved wettability and enhanced diffusion of dissolved nitrogen. Thus, within a minute of APADR, Al matrix composites (AMCs) containing AlN over 50 vol% were successfully fabricated by the infiltration of Al melt into Si<SUB>3</SUB>N<SUB>4</SUB> particulate preforms with different particle size distributions. The microstructures of the composites exhibited co-continuous three-dimensional network structures with strong interfacial bonding and high interfacial thermal conductance, which resulted in a unique combination of relatively high flexural strength and high thermal conductivity. In particular, the AMCs containing nitrides of 73 vol% exhibited a low coefficient of thermal expansion, close to that of GaAs or GaN used for high-power semiconductor devices, which is the lowest value ever reported among the nitride reinforced AMCs. These results would give us a promising strategy for in-situ processing routes to fabricate continuous nitride reinforced AMCs with high dimensional and mechanical stability for heat spreader applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We propose in-situ synthesis of co-continuous AlAlN composites via APADR process. </LI> <LI> The process combines a pressureless infiltration with volume nitridation by APADR. </LI> <LI> Within a minute of the process, Al composite with AlN over 50 vol% was fabricated. </LI> <LI> The AlAlN composites exhibit 3D network structure with strong interfacial bonding. </LI> <LI> The composites with tailored properties can be used for heat-spreader applications. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>