32 KB202 KB27 KB200020242008Barišić, NevenBilušić, AnteDolinšek, JanezLeontić, BoranLukatela, JagodaSmiljanić, IgorSmontara, AnaStanić, Denisštevilka:3letnik:42str. 105-110ISSN:1580-2949COBISSID:677802URN:URN:NBN:SI:doc-9D4NK0PCenInštitut za kovinske materiale in tehnologijeMateriali in tehnologijealuminijeve zlitinealuminium alloyelektrična prevodnostpaladijeve zlitinevpliv temperatureLow-temperature transport properties of the epsilon-phases Al-Pd-(Mn, Fe, Co, Rh)| Nizkotemperaturne transportne lastnosti epsilon-faz Al-Pd-(Mn, Fe, Co, Rh, ...)|We report results on low-temperature investigations of the electrical and thermal conductivity of the epsilon-phases in the Al-Pd-Fe, Al-Pd-Co and Al-Pd-Rh systems, which are characterized by giant unit cells with a quasicrystals-like cluster substructure. The electrical resistivity is of the order of 100 muOmega cm and shows a weak temperature dependence in the investigated temperature interval 4-300 K. An interesting feature of the epsilon-phases is their low thermal conductivity, which at room temperature is comparable to that of thermally insulating amorphous SiO2 and Zr/YO2 ceramics. While SiO2 and Zr/YO2 are also electrical insulators, epsilon-phases exhibit an electrical conductivity typical of metallic alloys and offer an interesting combination of an electrical conductor and a thermal insulator. The reason for the weak thermal conductivity of the epsilon-phases appears to be structural: large and heavy atomic clusters of icosahedral symmetry in the giant unit cell prevent the propagation of extended phonons and the lattice can no more efficiently participate in the heat transportPredstavljamo nizkotemperaturne raziskave električne in toplotne prevodnosti epsilon-faz v sistemih Al-Pd-Fe, Al-Pd-Co in Al-Pd-Rh, ki jih karakterizirajo velike celice s podstrukturo iz klasterjev kvazikristalov. Električna upornost je reda velikosti 100 miOmega cm in je malo odvisna od temperature v preiskanem intervalu 4-300 K. Zanimiva značilnost epsilon-faz je njihova majhna toplotna prevodnost, ki je pri sobni temperaturi primerljiva tisti pri toplotnih izolatorjih amorfnemu SiO2 in Zr/YO2-keramiki, ki pa sta električna izolatorja. Nasprotno, epsilon-faze imajo električno prevodnost, ki je značilna za kovinske zlitine in dajejo zanimivo kombinacijo električnega prevodnika in toplotnega izolatorja. Vzrok za majhno toplotno prevodnost epsilon faz so verjetno strukturni, veliki in težki klasterji atomov z ikozaedrično simetrijo, ki v veliki celici preprečujejo propagacijo razširjenih fononov, zato mreža ne more sodelovati učinkovito pri transportu toploteTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije