Zr-free glasses

Glass-forming ability has been also observed in several Zr-free fluoride systems, like in In-based glass systems whose... 

It should be noted that SSNMR experiments are performed on samples packed within a rotor made of a durable material, typically zirconia (Zr02). Unfortunately, this poses significant problems for Zr SSNMR experiments, as the signal from the sample and broad Zr background signal from the rotor are likely to overlap and complicate spectral interpretation [45]. For these reasons, static Zr SSNMR experiments often use a glass tube, while MAS experiments commonly employ a rotor made of Zr-free material (i.e., silicon nitride). 

Be NMR has been used to detect slow atomic motion of beryllium in Zr-Ti-Cu-Ni-Be metallic glasses. The results, obtained by a spin alignment echo technique, are consistent with Be diffusion occuring by a mechanism involving thermal fluctuations of the spread-out free volume rather than by vacancy-assisted or interstitial diffusion mechanisms (Tang et al. 1998). 

Potentiometric titration experiments of Zr chloride, nitrate, sulphate and perchlorate solutions were conducted at (25.00 + 0.05)°C until the onset of precipitation. Initial solutions (0.038, 0.019, 0.0095 and 0.0047 M in Zr) contained < 0.4% Hf and had an excess of 2 M of the acid of the anion studied. Titrations were performed with carbonate free 0.101 N NaOH. Glass electrodes where calibrated regularly but no correction for differences between liquid junction potential of reference and measured solutions was performed. The pH convention used was not reported and it is assumed that a NBS type convention was used. The pH at the onset of precipitation and coagulation of an uncharacterised and presumably amorphous solid were determined optically. The pH of coagulation was the pH at whieh the precipitate coagulated and the supernatant solution was clear. Reproducibility of these characteristic pH values was within 0.05 to 0.07 pH units. 

Oxide surfaces may be on ceramics, glasses, or metals. Adhesion to oxide surfaces is generally attained by having a contaminant-free surface and using an oxygen-active film material such as Ti, Cr, Mo, or Zr. To avoid stress problems, the film thickness should be limited (<500 A) and the desired film properties generated using a multilayer film structure. 

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