zirconium hafnium exposure


1. IDENTIFICATION OF THE SUBSTANCE/PREPARATION AND …

Eye contact Not an expected route of exposure for product in massive form. Skin Contact May cause sensitization by skin contact. Ingestion Not an expected route of exposure for product in massive form. Chemical Name Oral LD50 Dermal LD50 Inhalation LC50 Zirconium 5000 mg/kg bw - >4.3 mg/L Hafnium > 5000 mg/kg bw - >4.3mg/L

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Hafnium - Wikipedia

Hafnium is a shiny, silvery, ductile metal that is corrosion-resistant and chemically similar to zirconium (due to its having the same number of valence electrons, being in the same group, but also to relativistic effects; the expected expansion of atomic radii from period 5 to 6 is almost exactly cancelled out by the lanthanide contraction).Hafnium changes from its alpha form, a hexagonal ...

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Hafnium - Periodic Table of Elements: Los Alamos National ...

Exposure Limits. NIOSH REL TWA 5 mg/m 3 ST 10 mg/m 3 [*Note: The REL applies to all zirconium compounds (as Zr) except Zirconium tetrachloride.] OSHA PEL TWA 5 mg/m 3 See Appendix G. Measurement Methods. NIOSH 7300, 7301, 9102; OSHA ID121 See: …

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Why Does Zirconium Explode? How to Solve It? – Zirconium …

All processes using zirconium and hafnium should be designed and ventilated to keep air pollution below exposure limits. Stanford Advanced Materials supplies high-quality zirconium products to meet our customers' R&D and production needs.

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Atomic Layer Deposition of Hafnium and Zirconium Oxides ...

as DRAM.2 Both hafnium and zirconium oxides have high dielectric constants (at least 4 times that of silicon dioxide); thus, a thick film of hafnium or zirconium oxide can be used to achieve the high performance resulting from a thin silicon dioxide layer without the high leakage current associated with a thin layer of material.

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Zirconium and Hafnium - USGS

Zirconium and hafnium are typically contained in zircon at a ratio of about 36 to 1. Zirconium chemicals were produced by the metal producer in Oregon and by at least 10 other companies. Ceramics, foundry sand, opacifiers, and refractories are the leading end uses …

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Why Does Zirconium Explode? How to Solve It? – Zirconium Metal

All processes using zirconium and hafnium should be designed and ventilated to keep air pollution below exposure limits. Stanford Advanced Materials supplies high-quality zirconium products to meet our customers' R&D and production needs.

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Reactive Metals. Zirconium, Hafnium, and Titanium (Journal ...

Zirconium, Hafnium, and Titanium}, author = {Spink, Donald}, abstractNote = {The reactive metals ---zirconium, hafnium and titanium --are finding increased usage in the chemical process industry. Reduced cost, avai1ability, and an inertness to wide variations in chemical exposure are the three factors behind the acceptance of these transition ...

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High-temperature oxidation behavior of Nb–Si–Cr alloys ...

Highlights Oxidation behavior of two alloys from the Nb–Cr–Si system containing hafnium has been investigated under isothermal and cyclic conditions. A gravimetric method was used to determine oxidation kinetics; weight gain per unit area as a function of temperature or time. Oxidation experiments revealed good oxidation resistance for both alloys at 700 °C and 800 °C and …

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192 ZIRCONIUM AND HAFNIUM - USGS

Zirconium and hafnium are typically contained in zircon at a ratio of about 36 to 1. Zirconium chemicals were produced by the metal producer in Oregon and by at least 10 other companies. Ceramics, foundry sand, opacifiers, and refractories are the leading end uses …

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Hafnium | Hafnium

Likely Routes of Exposure: Inhalation, skin, eyes. Symptoms of Exposure: May cause irritation if dusts or fumes are inhaled or swallowed. Fines/dusts may irritate skin and eyes. Acute and Chronic Effects: Hafnium: Hafnium metal is a mild irritant of the eyes, skin, and mucous membranes. No industrial poisonings involving hafnium have been reported.

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Zirconium and hafnium: Old minerals finding new prominence ...

Hafnium is chemically similar to zirconium and separating the two elements is difficult. Because of this, most commercial hafnium is a by-product of zirconium refining. Zircon is the primary source of all hafnium, containing it at a ratio of about 50 to 1.

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Mechanical properties and corrosion resistance of hafnium ...

The mechanical properties of hafnium are redlmed slightly'when the zirconium content is increased from 3 to 25%. No appreciable deterioration in the mechanical properties of hafnium containing 3% zirconium is produced by prolonged exposure to a steam-water medium at 350-400° C.

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Hafnium - Periodic Table of Elements: Los Alamos National ...

Hafnium is a ductile metal with a brilliant silver luster. Its properties are considerably influenced by presence of zirconium impurities. Of all the elements, zirconium and hafnium are two of the most difficult to separate. Although their chemistry is almost identical, the density of zirconium is about half of hafnium.

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Has anyone worked with hafnium? : jewelry

The pure metal is not considered toxic, but hafnium compounds should be handled as if they were toxic because the ionic forms of metals are normally at greatest risk for toxicity." My personal opinion is this puts up red flags that if the rings are not done correctly there could be the possibility of toxic exposure so maybe you should reconsider.

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SAFETY DATA SHEET - NIST

Hafnium oxide (Hafnia, hafnium dioxide) Components are listed in compliance with OSHA's 29 CFR 1910.1200 . ... Inhalation exposure to zirconia in animals resulted in no detectable effects. Acute inhalation of yttria, a rare earth, has caused sensitivity to heat and itching. Prolonged exposure to rare earth oxides has resulted

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High-temperature oxidation behavior of Nb–Si–Cr alloys ...

The oxidation behavior of two alloys from the Nb–Si–Cr system containing hafnium has been investigated under isothermal and cyclic conditions. Nb–20Si–20Cr– (5,10)Hf alloys (composition in atomic percent) were exposed to air for 24 and 168 h over a range of temperatures from 700 °C to 1400 °C. A gravimetric method was used to ...

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Zirconium and hafnium - USGS

Zirconium and hafnium are likely not essential to human health and generally are considered to be of low toxicity to humans. The main exposure risks are associated with industrial inhalation and dermal exposure. Because of the low solubility of zirconium and hafnium, ecological health concerns in the aquatic environment and in soils are minimal.

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