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Coatings and Thin Films

Papers and patents relating to production of plasma-spray coatings.

Title: "Ultrashort pulsed laser vaporisation of icosahedral Al-Pd-Mn"

Authors: R. Teghil, L. D'Alessio, A. De Bonis, A. Galasso, P. Villani, M. Zaccagnino, A. Santagata, and D. J. Sordelet

Contact: D.J. Sordelet

Journal: Appl. Surf. Sci. (2005) 248, 304-308.

Abstract:
In this work, Al70Pd20Mn10 quasicrystalline targets were evaporated by a doubled Nd:glass laser with a pulse duration of 250 fs. The produced plasma has been analysed by time of flight mass spectrometry, optical emission spectroscopy and fast imaging. The results indicate that the plume is more complex as compared to other quasicrystalline systems with the presence of quite large clusters and with a higher ionisation degree. The analyses on the deposited films indicate that the vaporisation is not congruent.

Title: "Laser crystallization of amorphous sputter-deposited quasicrystalline coatings"

Authors: F. Kustas, P. Molian, A.S. Kumar, M. Besser, and D. Sordelet

Contact: D.J. Sordelet

Journal: Surf. Coat. Technol. (2004) 188-189, 274-280.

Abstract:
Quasicrystalline (QC) (e.g., Al70Fe10Cu10Cr10) materials offer a unique combination of relatively high hardness, low surface energy/low friction, and low thermal conductivity. This desirable suite of properties is reportedly due to their nonconventional translational symmetry and aperiodic atomic ordering. These materials can be formed only after a high-temperature (>700 °C) anneal, and they exhibit brittle behavior in bulk form. Coating deposition alleviates the low toughness issue, but the requirement for a high-temperature anneal degrades the mechanical properties of conventional engineering substrates. To address this latter issue, controlled laser surface treatment of sputter-deposited QC coatings (on Al, Ti, and bearing steel alloys) was performed to convert the amorphous (a) structure into a crystalline (c) phase. Characterization of both a-QC and c-QC films included energy dispersive spectroscopy (EDS) and X-ray diffraction for composition/structure, C-Brale indentation for relative toughness, and ball-on-disk (BOD) friction/wear tests. Laser treatment was successful in converting the amorphous structure to the crystalline phase, without significant reduction (<10% for Ti–6Al–4V) in substrate hardness, and it was shown that laser pulse energy influences the final surface finish of the c-QC surface. Laser crystallization was observed to increase the indentation resistance/adhesion of c-QC films on coated Ti–6Al–4V and 52100 steel. Friction/wear tests of c-QC films showed reductions in coefficients of friction, compared to non-coated substrates, of ∼40%, ∼20–25%, and ∼25–30%, respectively, for coated 2024-T3Al, Ti–6Al–4V, and AISI 52100 steel substrates. Reductions in wear damage for c-QC-coated surfaces, compared to non-coated surfaces, were also observed.

Title: "Electrocodeposited quasicrystalline coatings for non-stick wear resistant cookware"

Authors: Z. Minevski, C.L. Tennakoon, K.C. Anderson, C.J. Nelson, F.C. Burns, D.J. Sordelet, C.W. Haering, and D.W. Pickard

Contact: D.J. Sordelet

Journal: Mater. Res. Soc. Symp. Proc. (2004) 805, 345-350.

Abstract:
Lynntech, Inc has successfully researched and demonstrated a unique method for the manufacture of quasicrystalline (QC) coatings that utilizes the process of electrocodeposition. The purpose of this study was to optimize the physical-mechanical properties of the QC coatings. All metal substrates were aluminum alloy Al-3004 and codeposition was performed using Al65Cu23Fe12 QC powders in nickel plating solutions. X-ray diffraction spectroscopy was performed in order to verify the attachment of quasicrystals to the aluminum alloy substrate and coated samples displayed identical spectra to those of raw QC powders. The average contact angle è was 117.2° for electrocodeposited QC coatings. Friction was monitored during pin-on-disk wear tests and QC coated samples had coefficients of friction as low as 0.01 and an average value of 0.05 with samples showing no visible wear scar. Lynntech’s electrocodeposited quasicrystalline coatings withstand high temperatures and exhibit low wear and friction characteristics with a low surface energy making them ideal for cookware, as well as various other applications such as bearings, landing gear and engine parts, where thermal and mechanical conditions are prime importance.

Title: "Pulsed laser ablation and deposition of quasicrystals"

Authors: R. Teghil, L. D'Alessio, A. Santagata, A.R. Villani, P. Villani, A. Galasso, and D.J. Sordelet

Contact: D.J. Sordelet

Journal: ALT'02 International Conference on Advanced Laser Technologies, Edited by H.P. Weber, V.I. Konov and T. Graf. Proceedings of the SPIE (2003) 5147, 393-403.

Abstract:
The gaseous phase obtained by ablating a quasicrystalline AlCuFe target by nanosecond, piceosecond and femtosecond lasers, has been characterized by different techniques such as emission spectroscopy, quadrupole mass spectroscopy and ICCD imaging with the aim to study the plume composition, energy and morphology. To clarify the ablation process some films have been deposited, on oriented silicon, at different experimental conditions and analyzed by scanning electron microscopy, atomic force microscopy, energy dispersive x-ray analysis and x-ray diffraction. The results from nanosecond ablation show evidence of distinct albation mechanisms, which lead to different gas phase composition, as a function of the laser fluence. Films containing the quasicrystalline phase can be deposited only at fluences higher than about 6.5 J cm-2 while at lower fluences the aluminum content exceeds the stoichoimetric values. The results obtained from femtosecond and picosecond ablation show that the processes in the short pulse regimes ar very different to the nanosecond one. In particular the plume angular distribution shows a characteristic high cosine exponent and the composition of the deposits is completely stoichiometric and independent from the laser fluence, even if to obtain quasicrystalline films a substrate temperature of 600°C is needed.

Title: "Picosecond and femtosecond pulsed laser ablation and deposition of quasicrystals"

Authors: R. Teghil, L. D'Alessio, A. Santagata, M. Zaccagnino, D. Ferro, and D.J. Sordelet

Contact: D.J. Sordelet

Journal: Appl. Surf. Sci. (2003) 210, 307-317.

Abstract:

A Nd:glass laser with pulse duration of 250 fs and 1.3 ps has been used to evaporate a Al65Cu23Fe12 quasicrystalline target. The gaseous phase obtained from the ablation process has been characterised by several techniques such as emission spectroscopy, quadrupole mass spectrometry and ICCD imaging, used to study the plume composition, energy and morphology. The results show that the ablation processes in the short-pulse regimes are very different to the nanosecond one. In particular the plume angular distribution shows a characteristic high cosine exponent and the composition is completely stoichiometric and independent from the laser fluence. Furthermore the mass spectra indicate the presence of clusters, both neutral and ionised and the emission from the target suggest a rapid thermalisation leading to the melting of the surface. To clarify the ablation process some films have been deposited, on oriented silicon, at different experimental conditions and analysed by scanning electron microscopy, atomic force microscopy, energy dispersive X-ray analysis and X-ray diffraction. The analyses show the presence of nanostructured films retaining the target stoichiometry but consisting of different crystalline and non crystalline phases. In particular the nanostructure supports the hypothesis of the melting of the target during the ablation and a mechanism of material ejection is proposed for both picosecond and femtosecond regimes.

Title: "New approximants in the Al-Cr-Fe system and their oxidation resistance"

Authors: V. Demange, F. Machizaud, J.M. Dubois, J.W. Anderegg, P.A. Thiel, and D.J. Sordelet

Contact: D.J. Sordelet

Journal: J. Alloys Compd. (2002) 342, 24-29.

Abstract:

Two new orthorhombic approximants of the decagonal phase as well as a γ-brass type phase are pointed out in the Al–Cr–Fe system. Analysis of diffraction data shows that they are isotypic with compounds already known in the Al–Cu–Fe–Cr and Al–Cr alloys, respectively. Resistance to oxidation in water as well as at high temperature is significantly enhanced thanks to the addition of Cr.

Title: "Microstructural analysis of a FeAl/quasicrystal-based composite coating prepared using a focused ion beam miller"

Authors: J.M. Cairney, P.R. Munroe, and D.J. Sordelet

Contact: D.J. Sordelet

Journal: J. Microscopy (2001) 201, 201-211.

Abstract:

A composite consisting of a brittle multiphase matrix containing both an Al-based quasicrystalline phase (ψ) and an ordered body centred cubic phase (β) and a relatively ductile ordered body centred cubic intermetallic FeAl phase has been developed as an abrasive wear-resistant coating material. It is applied as a 500 μm thick layer onto stainless steel substrates through plasma spray processing. The microstructure of such materials can be readily examined by optical and scanning electron microscopy, but the inherent difficulty of preparing transmission electron microscope (TEM) samples has inhibited higher resolution studies. However, the relatively recent development of the focused ion beam (FIB) miller as a tool in materials science provides a method ideal for the preparation of TEM specimens of these materials. In this study a coating consisting of a mixture of an Al–Cu–Fe based quasicrystal and FeAl+Cr was deposited on to a 304 stainless steel substrate. TEM specimens were prepared using a FIB and subjected to detailed microstructural characterization. The structure consisted of elongated bands of a FeAl phase about 100 nm in width and several micrometres in length, which enclosed more equiaxed regions about 1 μm in diameter that consisted of fine mixtures of quasicrystal and two Al-Fe-Cu phases isostructurally related to FeAl.

Title: "Characterization of a commercially produced Al-Cu-Fe-Cr quasicrystalline coating"

Authors: D.J. Sordelet, S.D. Widener, Y. Tang, and M.F. Besser

Contact: D.J. Sordelet

Journal: Mater. Sci. Eng., A (2000) 294-296, 834-837.

Abstract:

A commercially produced Al–Cu–Fe–Cr thermal spray cookware coating was characterized. Gas-atomized powders with a nominal composition of Al71Cu10Fe8.5Cr10.5 were apparently used to form the coatings. The coating is very uniform and contains a quasicrystalline icosahedral phase along with a second phase that is either a quasicrystalline decagonal phase or its nearly identical crystalline approximant. The phases show evidence of structural imperfection and appear to be in a highly transitional state, which is likely caused by the rapid cooling during thermal spraying. A large fraction of unmelted particles and microcracks were observed throughout the coating.

Title: "Pulsed laser ablation of AlCuFe quaiscrystals"

Authors: R. Teghil, L. D'Alessio, M.A. Simone, M. Zaccagnino, D. Ferro, and D.J. Sordelet

Contact: D.J. Sordelet

Journal: Appl. Surf. Sci. (2000) 168, 267-269.

Abstract:

Quasicrystalline Al65–Cu23–Fe12 targets have been ablated by a doubled Nd:YAG laser and deposited on silicon substrates. The results show evidence of distinct ablation mechanisms, which lead to different gas phase composition, as a function of the laser fluence. Films containing the quasicrystalline phase can be deposited only at fluences higher than about 6.5 J/cm2 while at lower fluences the aluminium content exceeds the stoichiometric value. The films obtained by laser ablation of quasicrystalline Al65–Cu23–Fe12 were compared with those obtained from the metallic alloy Al70–Cu20–Fe10. The differences between the two systems could be explained on the basis of the low thermal conductivity of the quasicrystalline phase.

Title: "Quasicrystalline coatings: Thermal evolution of structure and properties"

Authors: C.I. Lang, D.J. Sordelet, M.F. Besser, D. Shechtman, F.S. Biancaniello, and E.J. Gonzales

Contact: D.J. Sordelet

Journal: J. Mater. Res. (2000) 15, 1894-1904.

Abstract:

Quasicrystals (QCs) are known to exhibit unique properties as a result of their unique quasiperiodic structure. Real quasicrystalline (QC) materials, however, may exhibit complex phase structures, and as a consequence, their properties may differ from expectations. In the present work, QC coatings of the Al-Cu-Fe, Al-Cu-Fe-Cr, and Al-Pd-Mn systems were prepared by a plasma spray process, followed by heat treatments in the range 500-800 °C. The phase structure and evolution of the coatings were evaluated, and thermal diffusivity, hardness, and friction coefficient were measured. The presence of quasicrystalline and crystalline phases and their influence on these properties is systematically considered for the first time. Broadly, the coatings exhibit the properties expected of QC materials, low thermal diffusivity, high hardness, and low coefficients of friction, but it is also shown that these properties can be sensitive to the phase structure of the coatings. This suggests that phase structure may be manipulated by heat treatment to optimize the properties of QC coatings.

Title: "Dry sliding of polygrained quasicrystalline and crystalline Al-Cu-Fe alloys"

Authors: D.J. Sordelet, J.S. Kim, and M.F. Besser

Contact: D.J. Sordelet

Journal: Mater. Res. Soc. Symp. Proc. 553, 459-470 (1999).

Abstract:

Dry sliding friction and wear expts. were performed with pin-on-disk techniques using WC and brass pins in contact with quasicryst. (Al65Cu23Fe12) and cryst. (Al50Cu35Fe15 and Al70Cu20Fe10) disks, which were prepd. by powder metallurgy routes. The contact loads (1, 5 and 10 N) used in this study produced similar coeffs. of friction 0.3-0.4 for the Al65Cu23Fe12 and Al50Cu35Fe15 phases. These values are higher than previously reported for quasicryst. and related cryst. phases. Possible reasons for these differences are presented. The contrasting wear behavior between different pins and disks is discussed in terms of contact area, oxidn., material transfer mechanisms and fracture characteristics.

Title: "Abrasive wear behavior of Al-Cu-Fe quasicrystalline composite coatings"

Authors: D.J. Sordelet, M.F. Besser, and J.L. Logsdon

Contact: D.J. Sordelet

Journal: Mater. Sci. Eng., A (1998) 255, 54-56.

Abstract

Quasicrystals are a relatively new class of materials which exhibit unusual atomic structure and useful physical and chemical properties. The inherent brittleness of quasicrystals has limited their potential use to primarily surface coating applications. This study examined the effect on abrasive wear behavior of Al–Cu–Fe quasicrystalline coatings through the addition (e.g. 0–100 v/o) of a relatively ductile Fe–Al phase. Coatings were deposited by plasma arc spraying techniques. The incorporation of discrete Fe–Al particles into the quasicrystalline coating matrix improves the abrasive wear resistance. Moreover, it is observed that low-level additions of the Fe–Al phase (e.g. 1 v/o) produce the most abrasive wear-resistant coating. The wear behavior of the quasicrystalline and composite coatings is discussed in terms of wear mode and coating hardness.

Title: "Dry sliding of polygrained quasicrystalline and cyrstalline Al-Cu-Fe alloys"

Authors: D.J. Sordelet, J.S. Kim, and M.F. Besser

Contact: D.J. Sordelet

In Quasicrystals: Symposium Held November 30 to December 2, 1998, Boston, MA, Ed. by J.-M. Dubois, P.A. Thiel, A.-P. Tsai and K. Urban, Materials Research Society, Warrendale, 459-470 (1999).

Abstract:

Dry sliding friction and wear experiments were performed with pin-on-disk techniques using WC and brass pins in contact with quasicrystalline (Al65Cu23Fe12) and crystalline (Al50Cu35Fe15 and Al70Cu20Fe10) disks, which were prepared by powder metallurgy routes. The contact loads (1, 5 and 10 N) used in this study produced similar coefficients of friction 0.3-0.4 for the Al65Cu23Fe12 and Al50Cu35Fe15 phases. These values are higher than previously reported for quasicrystalline and related crystalline phases. Possible reasons for these differences are presented. The contrasting wear behavior between different pins and disks is discussed in terms of contact area, oxidation, material transfer mechanisms and fracture characteristics.

Title: "Thermal spray quasicrystalline coatings, Part 1: Relationships between processing, phase structure and splat morphology"

Authors: D.J. Sordelet, M.F. Besser, M.J. Kramer, S. DePalo, and S. Sampath

Contact: D.J. Sordelet

Thermal Spray: Meeting the Challenges of the 21st Century, Ed. C. Coddet, ASM International, Materials Park, OH, 467-472 (1998).

Abstract:

A study was performed to examine the effects of starting powder composition, substrate thermal conductivity, and substrate temperature on the composition and structure of individual Al-Cu-Fe splats formed during thermal spraying. The fraction of quasicrystalline phase which formed was found to depend on the chemistry and solidification history of the splats. Due to evaporative loss of Al produced splats closer to the desired composition, which yielded more of the quasicrystalline phase. Deposition onto lower thermal conducivity surfaces resulted in an increase in the quasicrystalline phase, as did solidification onto higher temperature substrates.

Title: "Deposition and applications of quasicrystalline coatings"

Authors: M.F. Besser and T. Eisenhammer

Contact: M.F. Besser

Journal: MRS Bulletin (1997) 22(11), 59-63.

Abstract:

The key to engineering a material lies in exploiting its beneficial characteristics while minimizing its inherent weaknesses. Whether the weakness is, for example, poor corrosion resistance or low hardness, applying a relatively thin coating of another material that mitigates the shortcoming of the underlying material is a practical solution allowing the composite pieces to be used in demanding environments. This method has been utilized in a wide variety of cases ranging from paint on wooden fences and ceramic thermal barriers on single-crystal superalloy turbine blades to tungsten carbide hard-facing layers on drilling equipment. Some materials may suffer from high cost and therefore are used as a thin layer to impart their desired propoerties. For instance, gold leaf is applied to buildings for appearance while diamond films are deposited onto normal cutting tools to improve their performance. The specific application typically dictates both the material and the deposition method for coating. The gold leaf does not need to offer much resistance to abrasion or mechanical stress in order to maintain its beautiful shine far into the future. In contrast the diamond film must be strongly adhered to the underlying cutting tool surface if it is to survive the punishing wear and thermal stresses of machining operations.

Title: "Structure and chemistry of Al-Cu-Fe quasicrystalline plasma sprayed coatings"

Authors: M.F. Besser and D.J. Sordelet

Contact: D.J. Sordelet

New Horizons in Quasicrystals: Research and Applications Conference Proceedings, ed. by A. I. Goldman, D. J. Sordelet, P. A. Thiel, and J. M. Dubois, World Scientific, Singapore, 288-295 (1997).

Abstract:

Two different size fractions and chemical compositions of the Al-Cu-Fe system were plasma arc sprayed to examine the effects of starting powders and application parameters on the resultant coatings. The study determined that smaller powders (e.g., +25µm, -45µm), while resulting in denser microstructures, led to an increased loss of Al which prevented the formation of the quasicrystalline (ψ) phase. It was found that the effect of this chemistry shift could be reduced by using a different gun configuration, larger starting powder, or by increasing the Al fraction in the starting powder composition. Some coatings which had sufficient Al required annealing to form the quasicrystalline phase.

Title: "Oxidation and phase evolution of Al63Cu25Fe12 quasicrystalline powders"

Authors: D.J. Sordelet, L.A. Gunderman, M.F. Besser, and A.B. Akinc

Contact: D.J. Sordelet

New Horizons in Quasicrystals: Research and Applications Conference Proceedings, ed. by A. I. Goldman, D. J. Sordelet, P. A. Thiel, and J. M. Dubois, World Scientific, Singapore, 296-303 (1997).

Abstract:

Studies were preformed to evaluate the oxidation and phase evolution of Al63Cu25Fe12 powders under flowing O2 at temperatures from 300 °C to 800 °C. Weight gain as a function of time and temperature was monitored using powders which were either initially single-phase quasicrystalline or a two-phase mixture of a quasicrystalline phase and a cubic crystalline phase. X-ray diffraction was used to follow the change in phases which occurred during oxidation. Diffusion controlled parabolic oxidation was observed up to 800 °C. The quasicrystalline phase was stable up to 650 °C, but at 675 °C began to transform into a cubic crystalline phase having a different composition than the cubic phase in the as-prepared powders.

Title: "Particle size effects on chemistry and structure of Al-Cu-Fe quasicrystalline coatings"

Authors: D.J. Sordelet, M.F. Besser, and I.E. Anderson

Contact: D.J. Sordelet

Journal: Journal of Thermal Spray Technology (1996) 5(2), 161-174.

Abstract:

Gas atomized Al63Cu25Fe12 powders of varying size fractions were plasma sprayed onto hot (~600°C) and cool (~25°C) substrates using Mach I and subsonic plasma gun configurations. The chemical composition and phase contents of coatings were determined. Furthermore, coatings were annealed in vacuum at 700°C for two hours to observe phase changes. It was found that finer particles (e.g., < 25 um) tend to vaporize Al during spraying, which shifts the coating composition away from the quasicrystalline (Ψ) single phase region in the Al-Cu-Fe phase diagram. Coatings deposited on hot substrates were denser, richer in the Psi phase, and harder than the corresponding coatings deposited onto cool substrates.

Title: "Effect of starting powder particle size and composition on chemistry and structure of Al-Cu-Fe quasicrystalline plasma sprayed coatings"

Authors: D.J. Sordelet and M.F. Besser

Contact: D.J. Sordelet

Thermal Spray: Practical Solutions for Engineering Problems, Ed. by C. C. Berndt and S. Sampath, ASM International, Materials Park, OH, 419-427 (1996).

Abstract:

A brief study was performed to examine the influence of starting powder composition starting powder particle size and spraying environment on the chemistry, phase assemblage and porosity of Al-Cu-Fe plasma sprayed coatings involving a quasicrystalline phase. It was found that a loss of Al during spraying results from the extremely low thermal conductivity of the quasicrystalline phase in the starting powders. This loss changes the bulk composition of the deposited coating and partially controls the phases that develop. Smaller starting powder particles tended to lose more Al and, therefore, form less of the quasicrystalline phase. Larger starting powder particles did not lose Al to the same degree, and produced coatings with more of the quasicrystalline phase. However, these powders produced coatings also had a higher amount of porosity.

Title: "Effects of boron on the solidification structure of an Al-Ce-Fe alloy"

Authors: D.J. Sordelet, T.A. Bloomer, M.J. Kramer, and O. Unal

Contact: D.J. Sordelet

Journal: J. Mater. Sci. Lett. (1996) 15, 935-939.

Abstract:

Not available.

Title: "Effect of starting powders on the control of microstructural development of Al-Cu-Fe quasi-crystalline plasma-sprayed coatings"

Authors: D.J. Sordelet, M.J. Kramer, and O. Unal

Contact: D.J. Sordelet

Journal: Journal of Thermal Spray Technology (1995) 4(3), 235-244.

Abstract:

Powders and plasma-sprayed coatings of an Al63Cu25Fe12 alloy containing a quasi-crystalline phase were charactarized by X-ray diffraction, electron microscopy, and differential thermal analysis. The relationships between powder and coating microstructures were examined. Powders were produced by casting and crushing and by gas atomization. Both techniques produced powders with multiple phases; cubic and comoclinic ternary structured were formed along with the face-centered icosahedral quasi-crystalline phase. There phases were also produced in the plasma-arc-sprayed coatings formed using different starting powders. Cooling rates during powder processing greatly affected the phase equilibria and scale of segregation of this alloy. Finer grain sizes in the plasma-sprayed coatings were obtained from the more chemically homogeneous gas-atomized powders.

Title: "Microstructural evolution, oxidation and wear of Al-Cu-Fe quasicrystalline coatings"

Authors: D.J. Sordelet, M.J. Kramer, I.E. Anderson, and M.F. Besser

Contact: D.J. Sordelet

Proceedings of the Fifth International Conference on Quasicrystals, 778-785 (1995).

Abstract:

Plasma arc sprayed coatings were prepared with two different size fraction starting powders having a nominal composition of Al63Cu25Fe12. Powders were obtained by crushing a cast ingot and by gas atomization. Coatings were characterized by electron microscopy, X-ray diffraction and chemical analysis. Oxidation tests were performed in dry oxygen at 500° and 700°C. Finer powders produced coatings with more of the cubic phase than coatings formed with coarser powders. The as-sprayed coatings developed different phases during oxidation. Wear tests of as-sprayed coatings were performed over a range of temperatures in a pin-on-disc arrangement against aluminum oxide. The coefficient of friction increased from around 0.44 at room temperature to near 0.60 at 600°C. Differences in wear behavior of the coatings were seen as a function of temperature.

Title: "Microstructure and wear behavior of quasicrystalline thermal sprayed coatings"

Authors: D.J. Sordelet, P.D. Krotz, R.L. Daniel, and M.F. Smith

Contact: D.J. Sordelet

1995 Advances in Thermal Spray Science and Technology: Proceedings of the 8th National Thermal Spray Conference, Ed. C. C. Berndt and S. Sampath. pp. 627-632.

Abstract:

An Al-Cu-Fe coating which forms a quasicrystalline phase is a potential candidate for replacing electro-deposited chromium on various components in the Space Shuttle Main Engine. Coatings were deposited by air and vacuum plasma spraying and by high-velocity oxygen-fuel spraying. Finer starting powders tended to lose Al during spraying, which affected the phase equilibrium of the coatings. Coatings which retained the starting powder composition were richer in the desired quasicrystalline phase. Ball-on-disk wear tests between 440C stainless steel ball and the Al-Fu-Fe coatings were performed. Coefficients of friction ranged from 0.60 to 1.2 for the different coatings.


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