Zirconium

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M T Frost - One of the best experts on this subject based on the ideXlab platform.

  • alloying of pure magnesium with mg 33 3 wt zr master alloy
    Materials Science and Technology, 2003
    Co-Authors: Ma Qian, D. Graham, L. Zheng, David H. Stjohn, M T Frost
    Abstract:

    AbstractTo capitalise on the strengthening potential of Zirconium as a potent grain refiner for magnesium alloys, the mechanisms of adding Zirconium to magnesium and its subsequent grain refining action need to be understood. Using a Mg- 33.3Zr master alloy (Zirmax supplied by Magnesium Elektron Ltd) as a Zirconium alloying additive, the influence of different alloying conditions on the dissolution of Zirconium in magnesium was investigated. It was found that owing to the highly alloyable microstructure of Zirmax, the dissolution of Zirconium was generally complete within a few minutes in the temperature range 730 to 780°C. Prolonging and/or intensifying stirring were found to have no conspicuous influence on further enhancing the dissolution of Zirconium. In all cases studied, the average grain size increased with increasing holding time at temperature while the total Zirconium content decreased. The finest grain structure and highest total Zirconium content corresponded to sampling immediately after sti...

  • Zirconium alloying and grain refinement of magnesium alloys
    Magnesium Technology, 2003
    Co-Authors: Ma Qian, David H. Stjohn, M T Frost
    Abstract:

    Factors that influence alloying Zirconium to magnesium with a Mg-33.3Zr master alloy and the subsequent grain refinement are discussed based on a large number of experiments conducted at the laboratory scale (up to 30 kg of melt). It is shown that the Zirconium particles released from the Zirmax(R) master alloy must be brought into thorough contact with the melt by an appropriate stirring process in order to attain a good dissolution of Zirconium. The influence of alloying temperature on the recovery of Zirconium was found to be negligible in the range from 680 to 780 degreesC. An ideal Zirconium alloying process should end up with both high soluble and high total Zirconium in the melt in order to achieve the best grain refinement in the final alloy. The distribution of Zirconium in the final alloy microstructure is inhomogeneous and almost all of the Zirconium in solution is concentrated in Zirconium-rich cores in the microstructure.

Hongshi Zhao - One of the best experts on this subject based on the ideXlab platform.

  • The preparation of nanoparticle Zirconium phosphate
    Materials Letters, 2007
    Co-Authors: Yingjun Feng, Xudong Zhang, Xingtao Jia, Hongshi Zhao
    Abstract:

    Nano-sized Zirconium phosphate was synthesized by the solvothermal method using stoichiometric amounts of inorganic Zirconium and phosphate salts by surfactant anilin (An) and polyoxyethylene sorbitan monooleate (Tween). The formation of Zirconium phosphate was investigated by means of XRD. The pure Zirconium phosphate crystalline phase was obtained under mild synthesis conditions; this indicated that ethanol replaced part of water as solvent favoring the formation of Zirconium phosphate. TEM showed that Zirconium phosphate particles were basically regular in shapes, which included cube, hexagon and sphere. These particles were well dispersed and the mean grain size was about 100 nm, meanwhile, the successive processes occurring during the growth of hexagonal structure were investigated through TEM. SEM proved again that the morphology of Zirconium phosphate was regular and most particles had similar grain size.

Mohammad R. Islam - One of the best experts on this subject based on the ideXlab platform.

  • Preparation of Some Useful Compounds of Zirconium from Bangladeshi Zircon
    Industrial & Engineering Chemistry Research, 2012
    Co-Authors: Ranjit Kumar Biswas, M. A. Habib, Aneek Krishna Karmakar, Mohammad R. Islam
    Abstract:

    A number of useful Zirconium compounds, such as hydrated zirconyl chloride, hydrated Zirconium sulfate, Zirconium dioxide, γ-Zirconium ammonium phosphate, γ-Zirconium phosphate, γ-Zirconium phosphate phosphite, and γ-Zirconium phosphate hypophosphite have been prepared from Bangladeshi zircon following the NaOH-fusion, acid (HCl and H2SO4)-leaching, precipitation, calcination/pyrolysis, condensation polymerization, ion exchange and the tap tactic reaction methods. The products have been characterized by chemical and thermogravimetric analyses in all cases, together with the XRD patterns and sodium exchange capacities in some cases.

Ma Qian - One of the best experts on this subject based on the ideXlab platform.

  • alloying of pure magnesium with mg 33 3 wt zr master alloy
    Materials Science and Technology, 2003
    Co-Authors: Ma Qian, D. Graham, L. Zheng, David H. Stjohn, M T Frost
    Abstract:

    AbstractTo capitalise on the strengthening potential of Zirconium as a potent grain refiner for magnesium alloys, the mechanisms of adding Zirconium to magnesium and its subsequent grain refining action need to be understood. Using a Mg- 33.3Zr master alloy (Zirmax supplied by Magnesium Elektron Ltd) as a Zirconium alloying additive, the influence of different alloying conditions on the dissolution of Zirconium in magnesium was investigated. It was found that owing to the highly alloyable microstructure of Zirmax, the dissolution of Zirconium was generally complete within a few minutes in the temperature range 730 to 780°C. Prolonging and/or intensifying stirring were found to have no conspicuous influence on further enhancing the dissolution of Zirconium. In all cases studied, the average grain size increased with increasing holding time at temperature while the total Zirconium content decreased. The finest grain structure and highest total Zirconium content corresponded to sampling immediately after sti...

  • Zirconium alloying and grain refinement of magnesium alloys
    Magnesium Technology, 2003
    Co-Authors: Ma Qian, David H. Stjohn, M T Frost
    Abstract:

    Factors that influence alloying Zirconium to magnesium with a Mg-33.3Zr master alloy and the subsequent grain refinement are discussed based on a large number of experiments conducted at the laboratory scale (up to 30 kg of melt). It is shown that the Zirconium particles released from the Zirmax(R) master alloy must be brought into thorough contact with the melt by an appropriate stirring process in order to attain a good dissolution of Zirconium. The influence of alloying temperature on the recovery of Zirconium was found to be negligible in the range from 680 to 780 degreesC. An ideal Zirconium alloying process should end up with both high soluble and high total Zirconium in the melt in order to achieve the best grain refinement in the final alloy. The distribution of Zirconium in the final alloy microstructure is inhomogeneous and almost all of the Zirconium in solution is concentrated in Zirconium-rich cores in the microstructure.

Ferdi Schuth - One of the best experts on this subject based on the ideXlab platform.

  • highly ordered porous zirconias from surfactant controlled syntheses Zirconium oxide sulfate and Zirconium oxo phosphate
    Chemistry of Materials, 1999
    Co-Authors: Ulrike Ciesla, Michael Froba, Gale D Stucky, Ferdi Schuth
    Abstract:

    The syntheses and characterization of mesostructured hexagonally ordered surfactant composites using Zirconium sulfate ions as inorganic precursor species are described. On the basis of the mesostructured Zirconium sulfate surfactant composites, two porous MCM-41 analogues have been synthesized:  Zirconium oxide−sulfate and Zirconium oxo phosphate. For the Zirconium oxo phosphates, a special postsynthetic treatment has been developed. The pore arrangements and wall structures were characterized by XRD, nitrogen adsorption, EXAFS, and TEM. The porous zirconia based materials show hexagonal arrangements of uniformly sized pores and amorphous pore walls. Both Zirconium oxide−sulfate and Zirconium oxo phosphate show remarkable thermal stability up to 500 °C. Therefore, the surfactant has been completely removed from the structures by calcination. So far, this is the highest thermal stability compared to other porous transition metal oxides prepared via surfactant-controlled synthesis.