The metallurgy and functional properties of hafnium

Tricot, R

doi:10.1016/0022-3115(92)90382-u

Cited by 30 publications

(22 citation statements)

References 5 publications

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“…Hafnium is always found associated with zirconium in ores and is primarily found in zircon, with a ratio Hf/Zr of about 2.5%. 2 Due to a number of interesting properties such as high ductility and strength, and resistance to corrosion and mechanical damage, 3 it has attracted interest for various applications. For instance, it is used as a control material for nuclear reactors and as an alloying element in some superalloys used in aircrafts engines.…”

Section: Introductionmentioning

confidence: 99%

Corrosion and tribocorrosion of hafnium in simulated body fluids

2013

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Hafnium is a passive metal with good biocompatibility and osteogenesis, however, little is known about its resistance to wear and corrosion in biological environments. The corrosion and tribocorrosion behavior of hafnium and commercially pure (CP) titanium in simulated body fluids were investigated using electrochemical techniques. Cyclic polarization scans and open circuit potential measurements were performed in 0.9% NaCl solution and 25% bovine calf serum solution to assess the effect of organic species on the corrosion behavior of the metal. A pin-on-plate configuration tribometer and a three electrode electrochemical cell were integrated to investigate the tribocorrosion performance of the studied materials. The results showed that hafnium has good corrosion resistance. The corrosion density currents measured in its passive state were lower than those measured in the case of CP titanium; however, it showed a higher tendency to suffer from localized corrosion, which was more acute when imperfections were present on the surface. The electrochemical breakdown of the oxide layer was retarded in the presence of proteins. Tribocorrosion tests showed that hafnium has the ability to quickly repassivate after the oxide layer was damaged; however, it showed higher volumetric loss than CP titanium in equivalent wear-corrosion conditions.

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Section: Introductionmentioning

confidence: 99%

Corrosion and tribocorrosion of hafnium in simulated body fluids

2013

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“…A large portion of the entire processing facility for the production of Zr and Hf metals is dedicated to handling a multiple-step solvent extraction process in the presence of a solvent. Furthermore, it also generates a huge volume of liquid waste, which is difficult to dispose of due to stringent environmental protection laws [17][18][19][20]. For example, isobutyl methylketone (MIBK), which is the most popular solvents used for Zr-Hf extraction, requires environmentally harmful cyanogen (CN) chemicals as an additive.…”

Section: Introductionmentioning

confidence: 99%

Design of an Extractive Distillation Column for the Environmentally Benign Separation of Zirconium and Hafnium Tetrachloride for Nuclear Power Reactor Applications

et al. 2015

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Nuclear power with strengthened safety regulations continues to be used as an important resource in the world for managing atmospheric greenhouse gases and associated climate change. This study examined the environmentally benign separation of zirconium tetrachloride (ZrCl4) and hafnium tetrachloride (HfCl4) for nuclear power reactor applications through extractive distillation using a NaCl-KCl molten salt mixture. The vapor-liquid equilibrium behavior of ZrCl4 and HfCl4 over the molten salt system was correlated with Raoult's law. The molten salt-based extractive distillation column was designed optimally using a rigorous commercial simulator for the feasible separation of ZrCl4 and HfCl4. The molten salt-based extractive distillation approach has many potential advantages for the commercial separation of ZrCl4 and HfCl4 compared to the conventional distillation because of its milder temperatures and pressure conditions, smaller number of required separation trays in the column, and lower energy requirement for separation, while still taking the advantage of environmentally benign feature by distillation. A heat-pump-assisted configuration was also explored to improve the energy efficiency of the extractive distillation process. The proposed enhanced configuration reduced the energy requirement drastically. Extractive distillation can be a promising option competing OPEN ACCESSEnergies 2015, 8 10355 with the existing extraction-based separation process for zirconium purification for nuclear power reactor applications.

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“…[3][4][5] Fused salt electrorefining in a bath of molten alkaline chlorides is an available process to prepare a high purity Hf with low nitrogen, but it is difficult to operate for refining of Hf on a large scale and then has not yet to be applied practically. On the other hand, the iodide process and EBM are commercially used for purification of Hf.…”

Section: Introductionmentioning

confidence: 99%

“…However, Ti, Zr and Fe in Hf can not be eliminated efficiently and furthermore the cost of this process is very high, due to its low productivity. 3,4) Therefore, a more efficient and practical refining and purification method for Hf has been required. So, in this work, the purification of Hf has been examined by hydrogen plasma arc melting that we developed.…”

Section: Introductionmentioning

confidence: 99%

“…However, it has been reported that some metallic impurities such as Ti, Fe, Cu and Al in Hf could not be reduced to less than 10 mass ppm, respectively, by EBM. 3,5) The iodide refining process is also an effective method to decrease a plenty of metallic impurities like Mg and Cr and some nonmetallic impurities like O and N in Hf. However, Ti, Zr and Fe in Hf can not be eliminated efficiently and furthermore the cost of this process is very high, due to its low productivity.…”

Section: Introductionmentioning

confidence: 99%

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Purification of Hafnium by Hydrogen Plasma Arc Melting

2011

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Purification of two kinds of Hf metal, a high-purity Hf (HP-Hf) with 99.7 mass% and a low-purity Hf (LP-Hf) with 98 mass%, by hydrogen plasma arc melting (HPAM) has been carried out and the removal behavior of various impurity elements has been examined. Many metallic impurities (Fe, Al, Cr, Cu, Mn, Sn, Ti etc.) in the melted Hf, with higher vapor pressures than that of Hf, were removed to the very low levels by vaporization during HPAM and their removal rates increased with the hydrogen content of plasma arc. Then, the purity (except for Zr, O, N and C) of LP-Hf and HP-Hf were improved to nearly 99.998% and above 99.999%, respectively, after 60 min of 20%H 2 +Ar plasma arc melting. For the removal of Fe, Al, Cu and Ti from Hf, the refining effect of HPAM under atmospheric pressure was found to be superior to that of EBM under high vacuum. Therefore, HPAM has been confirmed to be a very useful method for the purification of Hf and the dissociated and activated hydrogen atoms formed in the high temperature plasma arc must play an important role for the unique refining process of HPAM.

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The metallurgy and functional properties of hafnium

Cited by 30 publications

References 5 publications

Corrosion and tribocorrosion of hafnium in simulated body fluids

Corrosion and tribocorrosion of hafnium in simulated body fluids

Design of an Extractive Distillation Column for the Environmentally Benign Separation of Zirconium and Hafnium Tetrachloride for Nuclear Power Reactor Applications

Purification of Hafnium by Hydrogen Plasma Arc Melting

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