Fabrication of flexible Ir and Ir-Rh wires and application for thermocouple

Murakami, Rikito; Kamada, Kei; Shoji, Yasuhiro; Yokota, Yuui; Yoshino, Masao; Kurosawa, Shunsuke; Ohashi, Yuji; Yamaji, Akihiro; Yoshikawa, Akira

doi:10.1016/j.jcrysgro.2018.01.018

Cited by 16 publications

(24 citation statements)

References 9 publications

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“…[36] Iridium (Ir), platinum (Pt), ruthenium (Ru), and their alloy fibers can be fabricated from the melt by the A-μ-PD method without the influence of their poor workability. [36][37][38] The Ir fibers fabricated using the A-μ-PD method were composed of elongated grains with a relatively large size, originating from unidirectional solidification, and the flexibility of Ir fibers was significantly improved compared with that of commercial Ir wires produced using the wire-drawing process. Therefore, the A-μ-PD method is appropriate for developing innovative fabrication techniques to produce thin fibers of various metals and alloys with poor workability.…”

Section: Introductionmentioning

confidence: 99%

Growth, Microstructure, and Mechanical Properties of Co–Cr–Mo Crystal Fibers Fabricated from the Melt by Unidirectional Solidification

et al. 2021

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Many complicated forming processes are required to fabricate thin wires of Co–Cr–Mo (CCM) biomedical materials due to the poor workability of these materials. A novel fabrication technique for CCM crystal fibers is developed by unidirectional solidification directly from the melt using the alloy‐micro‐pulling‐down (A‐μ‐PD) method. Compared with conventional methods, the proposed technique is an innovative fabrication method for CCM alloy fibers and is characterized by low cost, time saving, and low loading. In addition, the proposed method shows potential for further thinning of fibers. At growth rates of 0.1 and 0.3 mm min−1, CCM single‐crystal fibers composed of the ε‐phase with a hexagonal close‐packed (hcp) structure (hcp ε‐phase) can be fabricated. The hcp‐ε‐phase CCM crystal fibers exhibit considerably improved strain because of the slipping line in the hcp structure. Moreover, the γ‐phase with an fcc structure (fcc γ‐phase) appears in the hcp‐ε‐phase at growth rates greater than 0.5 mm min−1, and the ratio of the fcc γ‐phase in the CCM crystal fibers systematically increases with an increase in the cooling rate. The results reveal that the growth rate in the A‐μ‐PD method has a notable effect on the fabrication of single‐ or polycrystalline CCM fibers.

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Section: Introductionmentioning

confidence: 99%

Growth, Microstructure, and Mechanical Properties of Co–Cr–Mo Crystal Fibers Fabricated from the Melt by Unidirectional Solidification

et al. 2021

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“…Although the performance of Pt-based alloys was qualified for the demands of new-generation engines [7,8,9], their application temperature, service life, and cost were still not optimal. Compared with platinum, iridium has the advantages of a higher melting point, higher strength, and better corrosion resistance [10]. Use of Ir and Ir-based alloys as spark plug electrodes have improved engine ignition performance, extended service life, and reduced costs.…”

Section: Introductionmentioning

confidence: 99%

“…Ir can be rapidly oxidized or evaporated in an oxygen-enriched environment at high temperatures [14]. Since high-temperature oxidation resistance capacity is a crucial factor in improving spark plug performance [10,15], it is worthwhile to investigate the oxidation behavior of Ir–Rh alloys in the interest of minimizing the undesirable weight loss of alloys from Ir.…”

Section: Introductionmentioning

confidence: 99%

“…It has been reported that the main reason for weight loss is due to the formation of oxide species [10,16,17], and experiments have shown that the weight loss rate of iridium–rhodium alloys decreases with increasing rhodium content. However, to the best of our knowledge, no study has provided the reason that elemental Rh improves the oxidation-resistance capacity of Ir–Rh alloys [18,19].…”

Section: Introductionmentioning

confidence: 99%

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Microstructure and Isothermal Oxidation of Ir–Rh Spark Plug Electrodes

Zhao

Xia

et al. 2019

Materials

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High-temperature oxidation tests were performed on pure iridium, rhodium, and the iridium alloys, IrRh10, IrRh25, and IrRh40, at 1100 °C in a stable air environment for 60 h. The results of the oxidation were analyzed by X-ray photoelectron spectroscopy (XPS). Microstructural changes of the Ir–Rh alloys were characterized by scanning electron microscopy (SEM). XPS analysis results show that the main oxide of the Ir–Rh alloy in a 1100 °C environment was Rh2O3, and SEM analysis shows that the surfaces of the Ir–Rh alloys after oxidation formed both linear and ellipse-shaped corrosion pits, and had the same direction with the wire-drawing process. The oxidation behavior of Ir–Rh alloys, including the mass change, the reason for the mass loss, and the role of Rh in improving oxidation resistance performance, are discussed.

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“…The A-µ-PD method is based on the µ-PD method, which can grow inorganic single crystals from the melt, and various functional single crystals have been developed [15][16][17][18]. The A-µ-PD method can fabricate metal and alloy fibers with poor workability and a high melting point, and the diameter of the fabricated fiber can be controlled with accuracy to the submicron level [19]. In our previous reports, noble metal and alloy fibers such as iridium (Ir), ruthenium (Ru), platinum (Pt) and their alloys could be fabricated by the A-µ-PD method [14,19,20].…”

Section: Introductionmentioning

confidence: 99%

Control of Microstructure for Co-Cr-Mo Fibers Fabricated by Unidirectional Solidification

Abe

Yokota

Nihei³

et al. 2019

Crystals

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Co-Cr-Mo alloy fibers of 2 mm in diameter were fabricated from the melt at 1, 2, and 5 mm/min growth rates by unidirectional solidification using an alloy-micro-pulling-down (A-µ-PD) method to control the microstructure. All elements, Co, Cr, and Mo, were distributed in stripes elongated along the growth direction due to constitutional undercooling. Both Co-Cr-Mo fibers fabricated at 2 and 5 mm/min growth rates were composed of the γ phase with a face-centered cubic structure (fcc-γ phase) and ε-phase with a hexagonal close-packed structure (hcp-ε phase), and the ratio of the fcc-γ phase in the fiber fabricated at 5 mm/min growth rate was higher than that in the fiber fabricated at 2 mm/min. The results suggest that a faster growth rate increases the ratio of the fcc-γ phase in the Co-Cr-Mo fiber fabricated by unidirectional solidification.

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Fabrication of flexible Ir and Ir-Rh wires and application for thermocouple

Cited by 16 publications

References 9 publications

Growth, Microstructure, and Mechanical Properties of Co–Cr–Mo Crystal Fibers Fabricated from the Melt by Unidirectional Solidification

Growth, Microstructure, and Mechanical Properties of Co–Cr–Mo Crystal Fibers Fabricated from the Melt by Unidirectional Solidification

Microstructure and Isothermal Oxidation of Ir–Rh Spark Plug Electrodes

Control of Microstructure for Co-Cr-Mo Fibers Fabricated by Unidirectional Solidification

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