18 carat yellow gold alloys with increased hardness

Süss, R.; Lingen, Elma van der; Glaner, Lizelle; Toit, Madeleine Du

doi:10.1007/bf03215213

Cited by 30 publications

(16 citation statements)

References 12 publications

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“…The highest measured hardnesses were found for Co 33 W 07 Al 33 Nb 24 Cr 03 (1084 ± 37 HV) and Ti 18 Ni 24 Ta 12 Cr 22 Co 24 (1011 ± 20 HV) that have corresponding Pugh ductility ratios of P = 0.38 and P = 0.47, respectively (For comparison, the Vicker’s HV for alloys such as Ti-5Al, Ti-5V, and 75Au-7Cu-13Ag-5Co (wt. %) are 532.3, 429.3 and 128, respectively 44,45 ). Indeed, for each of the 7 candidate alloys identified here, P < 0.5.…”

Section: Resultsmentioning

confidence: 98%

Materials informatics for the screening of multi-principal elements and high-entropy alloys

et al. 2019

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The field of multi-principal element or (single-phase) high-entropy (HE) alloys has recently seen exponential growth as these systems represent a paradigm shift in alloy development, in some cases exhibiting unexpected structures and superior mechanical properties. However, the identification of promising HE alloys presents a daunting challenge given the associated vastness of the chemistry/composition space. We describe here a supervised learning strategy for the efficient screening of HE alloys that combines two complementary tools, namely: (1) a multiple regression analysis and its generalization, a canonical-correlation analysis (CCA) and (2) a genetic algorithm (GA) with a CCA-inspired fitness function. These tools permit the identification of promising multi-principal element alloys. We implement this procedure using a database for which mechanical property information exists and highlight new alloys having high hardnesses. Our methodology is validated by comparing predicted hardnesses with alloys fabricated by arc-melting, identifying alloys having very high measured hardnesses.

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Section: Resultsmentioning

confidence: 98%

Materials informatics for the screening of multi-principal elements and high-entropy alloys

et al. 2019

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“…Benda -benda fungsional yang lainnya seperti perhiasan, pena, jam tangan juga banyak terbuat dari emas. Bendabenda fungsional tersebut membutuhkan kekuatan, sehingga emas yang dipergunakan adalah emas paduan dengan logam yang lain seperti titanium, vanadium, chromium, molybdenum, cobalt, zirconium, boron, aluminium, silicon, zinc, platinum, palladium, rhodium, iridium dan ruthenium untuk meningkatkan nilai kekerasannya (Süss, Van Der Lingen, Glaner, & Du Toit, 2004); (Jotanović et.al., 2012).…”

Section: Kadar Emasunclassified

Kaji Ulang Sni 13-3487-2005 Barang – Barang Emas Dan Sni 13-3771-1995 Barang – Barang Emas Muda

et al. 2021

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Emas merupakan logam mulia yang dapat dijadikan investasi karena nilainya terus naik dari waktu ke waktu. Barang – barang emas dapat berbentuk batangan, granula, lembaran, perhiasan dan benda seni. Penjaminan mutu kadar emas diatur dalam SNI 13-3487-2005 Barang – barang emas dan SNI 13-3771-1995 Barang – barang emas muda. Pada saat ini emas yang beredar memiliki kadar mulai 3,33% hingga 99,99% (fine gold). Terdapat nilai kadar emas yang belum diatur dalam ke-dua SNI tersebut yaitu barang-barang emas dengan kadar 13,14,15,dan 16 karat. Sehingga perlu dilakukan pengujian untuk melihat kesesuaian kadar emas yang terkandung dalam barang – barang emas yang beredar di pasaran serta peninjauan kembali terhadap metode uji yang ada. Penelitian ini membahas hasil kaji ulang SNI 13-3487-2005 Barang – barang emas dan SNI 13-3771-1995 Barang – barang emas muda sebagai dasar penyusunan SNI barang – barang emas yang baru. Metode penelitian yang dilakukan adalah studi literatur, pengujian sampel barang – barang emas yang beredar yang diambil secara purposive sampling, kemudian dilakukan pengujian fire assay sesuai dengan SNI 13-3487-2005 Barang – barang emas dan ICP-OES sesuai dengan ISO 15093, Jewellery — Determination of precious metals in 999 0 / 00 gold, platinum and palladium jewellery alloys — Difference method using ICP-OES, kajian metode uji, dan penggalian informasi melalui rapat internal, rapat teknis dan rapat konsensus. Berdasarkan pembahasan maka dapat disimpulkan bahwa perlunya penggabungan dua SNI tersebut mencakup kadar 33,3% hingga 99,99%, menetapkan metode uji yang dipergunakan yaitu fire assay dan ICP-OES, dengan acuan normatif yang dipergunakan adalah standar ISO 11596 dan ISO 15039.

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“…This new material has mechanical properties comparable or superior to glassy plastics since the largest solid volume fraction (φ) is the organic polymer latex (φ Au = 14% v/v: Equation and Figure A) . Due to its unique properties, this material can significantly enhance the wear lifetime of watches and jewelry, also improving transport and material properties for radiation shielding applications (e.g., in space), catalysis, and electronics . As such, this new 18 karat gold can fill a niche which is currently unoccupied in the realm of industrially relevant gold blends and open the way to unexplored applications.…”

Section: Introductionmentioning

confidence: 99%

Light Gold: A Colloidal Approach Using Latex Templates

Hag

Handschin

Gschwend

et al. 2020

Adv Funct Materials

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A new 18 karat light gold, composed of gold single crystals, amyloids, and a polymer latex matrix is developed. It is similar to a glassy plastic, yet lighter than aluminum and of use in watches, jewelry, radiation shielding, catalysis, and electronics. The material is prepared via a hydrogel precursor dried into an aerogel. Annealing of the polystyrene matrix under vacuum gives rise to a homogeneous template. The final apparent density and porosity of the material depend directly on the volumetric concentration of the starting solution used for hydrogel formation. After annealing, a homogeneous microstructure is obtained in which the shining gold single crystal platelets are evenly embedded in a polystyrene matrix. The material has a glass transition temperature of ≈105 °C which allows for annealing and molding above this temperature. A general scaling behavior is found for the Young's modulus of the material with the density. The Young's modulus of the material with a density of 1.7 g cm−3 is ≈50 MPa. The density and stiffness, as well as the color, of the material can be tuned depending on the final application.

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18 carat yellow gold alloys with increased hardness

Cited by 30 publications

References 12 publications

Materials informatics for the screening of multi-principal elements and high-entropy alloys

Materials informatics for the screening of multi-principal elements and high-entropy alloys

Kaji Ulang Sni 13-3487-2005 Barang – Barang Emas Dan Sni 13-3771-1995 Barang – Barang Emas Muda

Light Gold: A Colloidal Approach Using Latex Templates

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