Optical properties of coloured platinum intermetallic compounds

Hurly, J.; Wedepohl, P T

doi:10.1007/bf00367841

Cited by 21 publications

(5 citation statements)

References 6 publications

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“…AuAl 2 is bright purple whereas PtAl 2 is yellow. Both compounds have been previously investigated for application in jewelry on account of their content of precious metals [10][11][12], while PtAl 2 is a useful barrier coating for jet engine turbine blades [13] and AuAl 2 has potentially attractive tribological [14] and decorative properties [15].…”

Section: Introductionmentioning

confidence: 99%

Nanoscale coatings of AuAlx and PtAlx and their mesoporous elemental derivatives

Cortie

Maaroof

Smith

et al. 2006

Current Applied Physics

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A method to produce nanoscale films of AuAl x and PtAl x , and their mesoporous elemental derivatives is described, and the morphology and optical properties of these coatings explored. The color of the AuAl x film is bright purple, in agreement with ab initio calculations and experimental observations for the compound AuAl 2 , but becomes black after de-alloying with NaOH. The film of PtAl x is silver-grey and changes to grey after being converted to mesoporous Pt by de-alloying. Both mesoporous coatings exhibit a very rough surface, with pores of between 2 and 20 nm in diameter, and display a significantly more absorptive optical characteristic compared to their ordinary elemental counterparts.

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Section: Introductionmentioning

confidence: 99%

Nanoscale coatings of AuAlx and PtAlx and their mesoporous elemental derivatives

Cortie

Maaroof

Smith

et al. 2006

Current Applied Physics

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“…For example, the C1-structured compounds PtAl 2 and AuAl 2 (which have anti-fluorite structures based on a geometric inversion of the structure of the compound CaF 2 [2]) are brassy yellow and metallic purple respectively. Both are known for producing eye-catching effects in specialized jewelry [3][4][5][6][7] and they have been the subject of a comprehensive recent investigation by Furrer and Spolenak [8]. The relatively unusual dielectric functions of PtAl 2 and AuAl 2 have also been previously investigated [4,[9][10][11][12][13][14][15] and their possible application in spectrally-selective filters or plasmonic devices discussed [4,9,10].…”

Section: Introductionmentioning

confidence: 99%

Thin films of PtAl2 and AuAl2 by solid-state reactive synthesis

et al. 2015

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The intermetallic compounds AuAl 2 and PtAl 2 are colored purple and yellow respectively. In the past they have been prepared by bulk melting techniques or by co-deposition in a magnetron sputterer. Here, however, we investigate films of AuAl 2 , PtAl 2 and (Au,Pt)Al 2 prepared by sequential physical vapor deposition of the elements, followed by in situ solid-state reaction. The microstructure, dielectric functions, optical properties and thermal stability of the resulting films are characterized and compared to those prepared by bulk melting or co-deposition. The (Au,Pt)Al 2 films show a color gamut that stretches from purple to brassy yellow depending on composition and microstructure. High temperature synchrotron X-ray diffraction experiments show that the (Au,Pt)Al 2 phase is metastable, decomposing when heated above 420 °C. In contrast, the pure AuAl 2 or PtAl 2 phases are stable to about 580 °C before they oxidize or decompose. The alternative possibility of producing the purple-to-yellow color gamut by depositing optical stacks of very thin films of AuAl 2 and PtAl 2 is also assessed. Either scheme will provide a range of colors lying between those of the binary compound endpoints. Calculations predict that deposition of AuAl 2 onto PtAl 2 will produce more intense colors than vice versa, an unexpected finding that is worth further investigation.

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“…According to the phase diagram, precursors with 0.60 < χ Al < 0.67 should have been 100% Al 3 Pt 2 at χ Al = 0.60 and 100% Al 2 Pt at χ Al = 0.67, with a duplex microstructure at intermediate stoichiometries. In the case of samples deposited at elevated temperature this was confirmed by XRD and visual examination, with the cubic diffraction pattern and characteristic brassy yellow color of Al 2 Pt becoming more prominent as χ Al approached 0.67. However, it was found to be essential to retard oxidation of Al during sample manufacture otherwise Al 3 Pt 2 formed at the expense of Al 2 Pt.…”

Section: Resultsmentioning

confidence: 69%

Effect of Precursor Stoichiometry on the Morphology of Nanoporous Platinum Sponges

Supansomboon

Porkovich

Dowd

et al. 2014

ACS Appl. Mater. Interfaces

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Nanoscale sponges formed by de-alloying suitable metallic alloys have a wide variety of potential applications due to their enhanced catalytic, optical, and electrochemical properties. In general, these materials have a bi-continuous, vermicular morphology of pores and ligaments with a fibrous appearance; however, other morphologies are sometimes reported. Here, we investigate how stoichiometry and process parameters control the characteristics of sponges formed from thin film precursors of AlxPt. Materials deposited at elevated temperatures and with mole fraction of Al between 0.65 and 0.90 produce the classic isotropic fibrous sponges with a morphology that varies systematically with precursor stoichiometry; however, de-alloying of material deposited at room temperature produced unusual isotropic foamy sponges. The evidence suggests that formation of a conventional fibrous sponge requires an equilibrated precursor whereas foamy morphologies will result if the precursor is metastable. Modeling was used to investigate the range of possible morphologies. As stoichiometry changed in the model system, the average mean and Gaussian curvature of the sponges systematically changed, too. The evolution of these shapes passed through certain special morphologies; for example, modelled structures with 0.80 Al had a zero average Gaussian curvature and might represent a structural optimum for some applications. These observations provide a means to control sponge morphology at the nanoscale.

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Optical properties of coloured platinum intermetallic compounds

Cited by 21 publications

References 6 publications

Nanoscale coatings of AuAlx and PtAlx and their mesoporous elemental derivatives

Nanoscale coatings of AuAlx and PtAlx and their mesoporous elemental derivatives

Thin films of PtAl2 and AuAl2 by solid-state reactive synthesis

Effect of Precursor Stoichiometry on the Morphology of Nanoporous Platinum Sponges

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