Thermal expansion of the Ti5Si3 and Ti6Si2B phases investigated by high-temperature X-ray diffraction

Rodrigues, Geovani; Nunes, Carlos Ângelo; Suzuki, Paulo Atsushi; Coelho, Gilberto Carvalho

doi:10.1016/j.intermet.2005.05.007

Cited by 46 publications

(18 citation statements)

References 27 publications

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“…Moreover, highly covalent-dominated atomic bonds endow Ti 5 Si 3 with good chemical inertness and high hardness, which has generated vigorous pursuit of Ti 5 Si 3 as a wear-and corrosion-resistant coating material. Unfortunately, since Ti 5 Si 3 has a hexagonal crystal structure, the thermal expansion anisotropy, originating from a large difference between the coefficients of thermal expansion (CTE) in the crystallographic c and a directions (CTE(c)/ CTE(a) ratios of $3), results in appreciable residual stresses in the material during heating and cooling that can give rise to microcracking [15,16]. To alleviate or eliminate this problem, alloying by substitutional elements, which acts to change the chemical bond nature and/or refine the crystal size, has been performed to control the degree of strain or microcracking.…”

Section: Introductionmentioning

confidence: 99%

Niobium addition enhancing the corrosion resistance of nanocrystalline Ti5Si3 coating in H2SO4 solution

Liu

et al. 2014

Acta Materialia

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nanocrystalline coatings were deposited onto Ti-6Al-4V substrates by a double glow discharge plasma technique. The effects of Nb alloying on the electrochemical behavior of the Ti 5 Si 3 nanocrystalline coatings were systematically investigated in a naturally aerated 5 wt.% H 2 SO 4 solution, for which various electrochemical techniques, including potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), potentiostatic polarization and Mott-Schottky analysis, were employed. Moreover, to evaluate the corrosion performance of the as-deposited coatings over an extended period, their corrosion resistance was analyzed after 7 days' immersion in a 5 wt.% H 2 SO 4 solution by EIS measurements and observations of corroded surface morphologies. The results showed that the Ti 62.5Àx Nb x Si 37.5 (x = 0, 6.3, 12.5) nanocrystalline coatings exhibit superior corrosion resistance compared with Ti-6Al-4V, and their corrosion resistance is enhanced with increasing Nb content, suggesting that Nb alloying is an effective strategy for improving the corrosion protection ability of the Ti 5 Si 3 nanocrystalline coating. The roles of Nb additions in enhancing the corrosion resistance of the Ti 5 Si 3 nanocrystalline coatings can be summarized as: (a) reducing the residual tensile stresses of the as-deposited coatings and (b) tailoring the composition, compactness and electronic structure of the passive films formed. These findings are expected to broaden the application of Ti 5 Si 3 as a highly corrosion-resistant coating for engineering components operating under aggressive conditions.

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Section: Introductionmentioning

confidence: 99%

Niobium addition enhancing the corrosion resistance of nanocrystalline Ti5Si3 coating in H2SO4 solution

Liu

et al. 2014

Acta Materialia

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“…Several studies [14][15][16][17][18][19] show that the 5:3 silicides can exhibit significantly different thermal expansion anisotropy values (ac/aa), ranging from 1.2 to 2.9. Table 1 presents crystallographic data and thermal expansion anisotropy values (ac/aa) for some 5:3 type silicides.…”

Section: Introductionmentioning

confidence: 99%

Thermal expansion of the V5Si3 and T2 phases of the V–Si–B system investigated by high-temperature X-ray diffraction

et al. 2009

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“…Williams et al [17] have shown that the a c /a a ratio for Ti 5 Si 3 could be reduced to approximately 2 by dissolution of a small amount of atoms such as C, B or N in its structure. A recent study [18] has identified a hexagonal phase in the TieSieB system with stoichiometry Ti 6 Si 2 B, which is isotropic with respect to thermal expansion [14].…”

Section: Introductionmentioning

confidence: 99%

Thermal expansion of the W5Si3 and T2 phases of the W–Si–B system investigated by high-temperature X-ray diffraction

et al. 2007

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The coefficients of thermal expansion (CTE) of the W 5 Si 3 and T 2 phases of the WeSieB system were determined using high-temperature X-ray diffraction in the 298e1273 K temperature interval. Alloys with nominal compositions 62.5W37.5Si (at%) and 58W21Si21B (at%) were prepared from high-purity materials through arc melting followed by heat treatment at 2073 K for 12 h under argon atmosphere. The highly different thermal expansion coefficients of W 5 Si 3 along the a (5.0 Â 10 À6 K À1 ) and c (16.3 Â 10 À6 K À1 ) axes lead to a high thermal expansion anisotropy (a c /a a y 3.3). On the other hand, the T 2 -phase exhibits similar thermal expansion coefficients along the a (6.9 Â 10 À6 K À1 ) and c (7.6 Â 10 À6 K À1 ) axes, indicating a behavior close to isotropic (a c /a a y 1.1).

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Thermal expansion of the Ti5Si3 and Ti6Si2B phases investigated by high-temperature X-ray diffraction

Cited by 46 publications

References 27 publications

Niobium addition enhancing the corrosion resistance of nanocrystalline Ti5Si3 coating in H2SO4 solution

Niobium addition enhancing the corrosion resistance of nanocrystalline Ti5Si3 coating in H2SO4 solution

Thermal expansion of the V5Si3 and T2 phases of the V–Si–B system investigated by high-temperature X-ray diffraction

Thermal expansion of the W5Si3 and T2 phases of the W–Si–B system investigated by high-temperature X-ray diffraction

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