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Structure and properties of Al-Cu-Fe thin films deposited by PLD technique

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Recent progress in the development of quasicrystals (QCs) as low- -friction, hard materials, makes these alloys ideal candidates for protective coatings. However one disadvantage of quasicrystals is that they are quite brittle. To overcome this problem, we are taking advantage of nonstructural materials and produce coatings, which consist of a nanograin quasicrystals and metal. Quasicrystals are alloys, which have long-range rotational symmetry, but lack translational periodicity in three dimensions. In spite of the lack of translational periodicity, these materials show sharp diffraction patterns with symmetries, which are forbidden for ordinary crystals (five-fold or ten-fold axes, for instance) [1]. Analysis of bibliography [2÷4] shows that quasicrystals exhibit intriguing surface properties in air. First of all, they have low coefficient of friction, low propensity to wetting by polar liquids, excellent oxidation resistance and high hardness. However, given that they are brittle materials they are usually employed as film coatings. Up to now, quasicrystalline phases have been observed in over 100 different metal alloy systems. One of the systems creating of quasicrystal phases are Al-Cu-Fe alloys. Their friction properties and hardness makes them an interesting material for wear-resistant coatings. Their low thermal conductivity and their improved ductility above 750°C make them suitable for thermal barrier coatings [2, 5, 7]. The production of good quality quasicrystalline Al-Cu-Fe alloys on an industrial scale is still difficult. Literature study shows, that is possible to form Al-Cu-Fe quasicrystals using different methods, like melting and solidification, melt spinning, gas atomization, mechanical alloying [2], and by PLD technique [4, 6, 8]. Literature study [9, 10] indicates that PLD technique which allows to transform stoichiometrically material from the target to film seems to be an ideal method for preparation of[...]

The AlMg thin films deposited by using PLD technique

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In the paper the systematic study of the pulsed laser deposition of B-Mg2Al3 has been carried out. The AlMg thin films were prepared on Si (100) substrates and deposited by using a Nd:YAG laser (A = 355 nm). The samples were performed with two different laser beam energy densities (4,7 and 10 J/cm2) and two different substrate (Si) temperatures (room temperature and 430 oC). The[...]

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