Hydro-quebec

Mcgill University

Rival Societe En Commandite

Sabin Boily

Robert Schulz

Jacques Huot

Guy Lalande

John O Strom-Olsen

Leszek Zaluski

Alicja Zaluska

Andre Van Neste

André Van Neste

Guoxian Liang

Shize Jin

Reynald Rioux

Rene Dubuc

Guoxiang Liang

Houshang Alamdari

Alain Joly

Marco Blouin

Andr&eacute; Van Neste

Serge Bujold

Erwann Fraboulet

Jin Shize

The invention concerns a method for preparing a nanocomposite based on magnesium and another element or compound known to absorb hydrogen and hardly miscible when ground with magnesium or its hydride, such as vanadium, titanium or niobium. The method is characterised in that it consists in submitting magnesium or a compound based on magnesium known to absorb hydrogen to hydrogenation to obtain the corresponding hydride in powder form. Said resulting powder hydride is then mixed with the other element or compound or a hydride of said other element or compound and the resulting mixture is subjected to intense mechanical grinding until the corresponding nanocomposite is obtained in the form of a hydride. Finally, if necessary, the resulting nanocomposite is subjected to hydrogen desorption. The invention also concerns the resulting nanocomposite based on Mg, which has the advantage of being inexpensive and highly efficient for storing hydrogen owing to its microstructure (that is owing to the nature of its interfaces and the spatial distribution of its constituents) which is extremely fine and provides an excellent synergistic effect between Mg and the other element or compound.

Nanocomposites with activated interfaces prepared by mechanical grinding of magnesium hydrides and use for storing hydrogen

The invention concerns a piece based on one or several metal hydrides capable of reversibly absorbing hydrogen. Said piece is in the form of a thin and dense band, having a thickness preferably not more than 1 mm and porosity preferably less than 20%. The piece is obtained by rolling a powder of selected hydride(s), with or without additional component(s), such as binders or heat-transfer elements. Said piece can easily be produced on an industrial scale. By its very nature, it is particularly adapted for use as a base element in a tank for storing and transporting hydrogen. It can also be used in a Ni-MH typre battery for storing and transporting energy.

Metal hydride bands and use thereof for storing hydrogen

The invention concerns novel varistors based on zinc oxide and a method for making same, which consists in using as base products nanocrystalline powders obtained by high-intensity mechanical grinding and in subjecting the mixture resulting from said nanocrystalline powders a consolidating treatment such as sintering, in suitably selected temperature and time conditions so as to retain the smallest possible grain size of ZnO. The resulting varistors have a very fine homogeneous microstructure and an average grain size characteristically not more than 3 mu m, i.e. five times smaller than standard materials. Said novel varistors have a larger number of grain boundaries per length unit and therefore a much higher breakdown voltage. Said voltage is characteristically higher than 10 kV/cm and can reach 17 kV/cm which is almost one order of magnitude above the breakdown voltage of standard varistors. The non-linearity coefficient of the current-voltage curve is also improved, and is greater than 20 and can reach values as high as 60. Moreover, the leakage currents below the breakdown voltage of said varistors, are much weaker.

Varistors based on nanocrystalline powders produced by mechanical grinding

The invention concerns an apparatus for the titration and circulation of gases to determine metal hydride storing properties, with improved response time, greater dynamic range in terms of the usable amount of powder and the maximum pressure accessible and increased sensitivity. The invention also concerns a circulating apparatus considerably reducing the time for analysing and determining the properties of absorbent and adsorbent materials during a large number of adsorption-desorption cycles. Both sets of apparatus are provided with a reference tube inside their oven, near the sample-holder. Said sample-holder tube and reference tube are connected on either side of the differential pressure sensor, thereby considerably enhancing the overall performance of the titration system.

Apparatus for titration and circulation of gases and circulation of an absorbent or adsorbent substance

An improved method is disclosed for producing gaseous hydrogen by subjecting a metal or a metal hydride to a chemical reaction. In this method, the metal or metal hydride subjected to the chemical reaction is nanocrystalline. Indeed, it has been found that when, instead of using conventional metal hydrides (Mg-based or others), use is made of a metal or metal hydride that is or has been subjected to intensive mechanical deformations, such as a metastable nanocrystalline metal hydride, then the chemical reaction, especially hydrolysis, will take place much more readily, at a much higher rate and, most of the time, up to completion.

Method for producing gaseous hydrogen by chemical reaction of metals or metal hydrides subjected to intense mechanical deformations

Disclosed is a nanocrystalline composite useful for hydrogen storage, which provides optimum hydrogenation conditions along with high hydrogen storage capacity. This composite is the combination of at least one high temperature metal hydride such as Mg or Mg.sub.2 Ni, which has a high hydrogen storage capacity by weight but requires high temperatures for hydrogen absorption and desorption, with at least one low temperature metal hydride such as FeTi, LaNi.sub.5, Nb, Mn or Pd, which has a low hydrogen storage capacity by weight but does not require high temperatures for hydrogen absorption and desorption. The high and low temperature metal hydrides are in direct contact with each other and each in the form of a nanocrystalline powder or layer. This composite is particularly useful as a hydrogen supply source for hydrogen-fueled vehicles.

Nanocrystalline composite for hydrogen storage

A process is described for preparing a nanocrystalline powder of an alloy of at least two metals by an intensive mechanical grinding step performed upon powders of the metals which make up the alloy. The grinding is performed at atmospheric pressure under an inert atmosphere, and is carried out at a temperature in the range of 100.degree.-400.degree. C. In this manner, one obtains crystallites of the alloy having a grain size lower than 100 nm by grinding for a period of time lower by about an order of magnitude than the time necessary to achieve this grain size by a similar grinding step carried out at ambient temperature.

Preparation of nanocrystalline alloys by mechanical alloying carried out

Alloys of Ti Ru Fe and O and use thereof for the manufacture of cathodes

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Chambly, Canada

Sabin Boily