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Thermal Conductivity Behaviour of Al/Diamond and Ag/Diamond Composites in the Temperature Range 4 K < T < 293 K

MetadataDetails
Publication Date2015-07-01
JournalMaterials science forum
AuthorsChristian Edtmaier, E. Bauer, Zeze Serge Tako, Jakob Segl
InstitutionsTU Wien
Citations2

Two different systems, the non-reactive Ag-diamond and the reactive Al-diamond system, were assessed by their thermal conductivity behaviour, both were fabricated by gas pressure assisted infiltration of densely packed diamond bulks with aluminium or silver and different Si-concentration and diamonds of varying particle sizes. The effect of Si-concentration on the interface thermal conductance h between Al, Ag and diamonds was investigated in dependence of temperature by measuring thermal conductivity of composites with different sized diamond particles in the temperature range from 4 K up to ambient. Composite thermal conductivities Îș c (T) can be as high as 860 W m -1 K -1 at roughly 100 K for Al/diamond and 1100 W m -1 K -1 for Ag-Si/diamond at approx. 150 K. Although the Si concentration in the matrix plays an eminent role for Îș c (T), i.e. the lower the Si concentration, the higher Îș c (T), interface thermal conductance is almost unaffected in the reactive Al-diamond system. Furthermore, they are close to values determined on clean model systems, i.e. sputtered and evaporated metal layers on diamond monocrystals. For Ag-diamond composites, the matrix composition of Ag-1Si seems to reflect an optimal composition, as the highest thermal conductivity Îș c (T) and an extraordinary higher interface conductance was achieved compared to Ag-3Si/diamond composites.