Role of Palladium in Hydrogen Absorption of Ti-Pd Alloy

Fukuzuka, Toshio; Shimogori, Kazutoshi; Satoh, Hiroshi

doi:10.3323/jcorr1974.29.12_622

Cited by 5 publications

(7 citation statements)

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“…These results are consistent with those of Fukuzuka et al [42], who showed enhanced proton reduction was possible at lower potentials on Pd-containing alloys than on Ti Grade 2. This indicates that redox transformations in the oxide are not a prerequisite for proton reduction.…”

Section: Metallurgical Aspects Of Titanium Alloyssupporting

confidence: 93%

“…Experimental evidence for the enhancement of hydrogen absorption due to Pd addition is not conclusive. Alloying Pd with titanium might promote hydrogen absorption [41], however other investigators showed that Ti-Pd alloys are not sensitive to hydrogen absorption [42,43]. Fukuzuka et al [42] demonstrated that, while the hydrogen absorption efficiency of Ti-Pd alloys increased with Pd content in deaerated HC1, both the corrosion rate and hydrogen absorption efficiency decreased when the HC1 was aerated.…”

Section: Effects Of Palladium and Other Alloying Additions On Hydrogementioning

confidence: 99%

“…Alloying Pd with titanium might promote hydrogen absorption [41], however other investigators showed that Ti-Pd alloys are not sensitive to hydrogen absorption [42,43]. Fukuzuka et al [42] demonstrated that, while the hydrogen absorption efficiency of Ti-Pd alloys increased with Pd content in deaerated HC1, both the corrosion rate and hydrogen absorption efficiency decreased when the HC1 was aerated. This influence of aeration was attributed to the ennoblement of the corrosion potential due to the addition of Pd, and to the low over-voltage of Pd for oxygen reduction.…”

Section: Effects Of Palladium and Other Alloying Additions On Hydrogementioning

confidence: 99%

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A Review Corrosion of TI Grade 7 and Other TI Alloys in Nuclear Waste Repository Environments

Fang¹,

Mon²,

Pasupathi³

et al. 2004

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IKoster [94] conducted SCC tests in aggressive chloride brines (some containing Mg and Ca) at 90, 170, and 200°C in the presence and absence of a gamma radiation field (lo5 rad/hr). They concluded that Ti Grade 7 was resistant to both localized corrosion and SCC in those environments.In test media relevant to the repository environments, SCC tests were conducted using U-bend (constant deflection) specimens of Ti Grades 7 and 12 [95]. The specimens were exposed for up to 4 years in SCW, SAW, and SDW solutions (Table 3) (Table 3) at 110°C and subjected to very low cyclic loading (-0.001 Hz).Crack length versus time was monitored in-situ using a reversing DC potential drop technique. A typical result is shown in Figure 15. The loading characteristics were modified at several times through the addition of long hold times at the maximum stress intensity factor (ISmax) culminating with a very long hold time (-2000 hours) about 4100 hours into the test. The crack growth rate to 800 pg/g (Ti Grade 2) and 400 to 600 pg/g (Ti Grade 12) have been determined [98,102].Ikeda and Quinn reported that the Hc value for Ti Grade 16 is between 1000 and 2000 pg/g [39,40]. . Since both Ti Grade 7 and Ti Grade 16 are virtually identical except for palladium content (Table 1) and are a-alloys containing minimal amounts of &phase, it is reasonable to expect that both alloys will exhibit very similar responses to applied stresses in acidic environments. Thus, the controlling factor in determining the Hc will be the solubility of the hydrogen in the alloy which increases with the Pd-content. This clearly suggests that the HIC behavior of Ti Grade 7 should be at least as good as that of Ti Grade 16 (Le. -1000 pg/g). Ikeda et al. studied the HIC behavior of Ti Grade 16 in comparison with TiGrades 2 and 12 [103, 1041 and concluded that the much higher Hc for Ti Grade 16 is due to prevention of hydride formation by the higher solubility of hydrogen in Pd intermetallic particles. The authors stated that intermetallic particles do not act as hydrogen absorption windows but may promote proton discharge favoring hydrogen gas production. 29An experimentally obtained critical hydrogen concentration for Ti Grade 24 is not available at this time. However, an approximate Hc value of this alloy can be inferred from the corrosion behavior of Ti Grade 5. Testing of Ti Grade 5 and its Pd-modified version, Ti Grade 24, showed that the addition of Pd improves the alloy's corrosion resistance in a manner similar to that observed when Pd is added to the Ti Grade 2 alloy to produce Ti Grade 16 [20, 27, 1051. For Ti Grade 5, Hardie and Ouyang showed that the fracture toughness was not significantly altered until the hydrogen level in the alloy exceeded 200 pg/g [106]. For smooth tensile specimens, the authors showed that the reduction in area and elongation of Ti Grade 5 did not decrease until the hydrogen concentration reached about 1,500 pg/g [ 1061. Addition of Pd to Ti Grade 5 (to produce Ti Grade 24) should lead to a higher value of Hc as it did for ad...

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Section: Metallurgical Aspects Of Titanium Alloyssupporting

confidence: 93%

Section: Effects Of Palladium and Other Alloying Additions On Hydrogementioning

confidence: 99%

Section: Effects Of Palladium and Other Alloying Additions On Hydrogementioning

confidence: 99%

See 1 more Smart Citation

A Review Corrosion of TI Grade 7 and Other TI Alloys in Nuclear Waste Repository Environments

Fang¹,

Mon²,

Pasupathi³

et al. 2004

View full text Add to dashboard Cite

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“…The significantly reduced Tafel values of -0.03 V to -0.05 V measured for the Ti-Pd alloy, however, indicates that either H ads recombination (Equation [3]) 59 or the electrodic desorption step (Equation [4]) 61 become rate determining, depending on the extent of absorbed hydrogen surface coverage (θ H ). Thus, the PGM-enriched surface "de-bottlenecks" and dramatically facilitates the hydrogen discharge step, such that the kinetically rapid hydrogen recombination/ desorption steps become rate limiting for the HER.…”

Section: Why Pgms Are Especially Potent Cathode Modifiersmentioning

confidence: 96%

“…Cathodic Tafel slopes determined for unalloyed titanium and Ti-Pd alloys in hot, dilute HCl solutions 59,61 indicate that the rate-determining step for titanium is normally the discharge step (Equation [2]). The significantly reduced Tafel values of -0.03 V to -0.05 V measured for the Ti-Pd alloy, however, indicates that either H ads recombination (Equation [3]) 59 or the electrodic desorption step (Equation [4]) 61 become rate determining, depending on the extent of absorbed hydrogen surface coverage (θ H ).…”

Section: Why Pgms Are Especially Potent Cathode Modifiersmentioning

confidence: 99%

2003 F.N. Speller Award Lecture:Platinum Group Metal Additions to Titanium: A Highly Effective Strategy for Enhancing Corrosion Resistance

Schutz¹

2003

CORROSION

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Although recognized for their exceptional corrosion resistance in a wide range of chemical environments, titanium and its alloys can be susceptible to corrosion in reducing acid media, crevice attack in hot chlorides and other halide solutions, and/or stress corrosion in certain higher-strength alloys. These serious limitations may be practically and costeffectively overcome to a great extent by the addition of very minor (<0.25 wt%) amounts of platinum group metals (PGMs) to titanium and its alloys; while imparting little or no effect on alloy mechanical/physical properties or metallurgy. Through the catalytic facilitation of cathodic reduction reactions (primarily the hydrogen evolution reaction [HER]) in acidic aqueous media, these PGM alloy additions shift titanium toward noble (positive) potentials where the protective titanium oxide surface film is stable. This radically decreases alloy corrosion rates in dilute inorganic and organic acids with no detrimental influence in oxidizing media or to hydrogen absorption resistance; and dramatically elevates alloy crevice and stress corrosion temperature threshold limits in aqueous chloride (halide) environments. Although any PGM may be effective, titanium alloys based on minimal Pd and/or Ru alloying additions have been commercialized and proven to be most cost-effective to date. This paper presents an overview of the commercial PGM-enhanced titanium alloys available today, their historical evolution and metallurgy, insight into corrosion-resistance enhancement mechanisms, the scope of expanded alloy corrosion performance limits achieved, relative cost impact, and relevant current and candidate applications.

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Hydriding of titanium: Recent trends and perspectives in advanced characterization and multiscale modeling

Zhu

Heo

Rodríguez

et al. 2022

Current Opinion in Solid State and Materials Science

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Role of Palladium in Hydrogen Absorption of Ti-Pd Alloy

Cited by 5 publications

References 0 publications

A Review Corrosion of TI Grade 7 and Other TI Alloys in Nuclear Waste Repository Environments

A Review Corrosion of TI Grade 7 and Other TI Alloys in Nuclear Waste Repository Environments

2003 F.N. Speller Award Lecture:Platinum Group Metal Additions to Titanium: A Highly Effective Strategy for Enhancing Corrosion Resistance

Hydriding of titanium: Recent trends and perspectives in advanced characterization and multiscale modeling

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