Porous metal hydride composite and preparation and uses thereof
AssigneeThe United States of America as represented by the United States Department of Energy
InventorsWilliam A. Steyert, Clayton E. Olsen
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Abstract
A composite formed from large pieces of aggregate formed from (1) metal hydride (or hydride-former) powder and (2) either metal powder or plastic powder or both is prepared. The composite has large macroscopic interconnected pores (much larger than the sizes of the powders which are used) and will have a very fast heat transfer rate and low windage loss. It will be useful, for example, in heat engines, hydrogen storage devices, and refrigerator components which depend for their utility upon both a fast rate of hydriding and dehydriding. Additionally, a method of preparing the composite and a method of increasing the rates of hydriding and dehydriding of metal hydrides are also given.
Claims19
A composite comprising:
- a plurality of aggregates arranged in a random array so that interconnected large pores having an average largest linear dimension C exist between individual aggregates, each of said aggregates comprising:
- (a) first powder particles comprising particles of an interstitial metal hydride and having an average largest linear dimension a after initial activation by hydriding, and
- (b) second powder particles comprising lead powder,
- wherein said first powder particles are separated from each other by said lead powder,
- wherein said first powder particles are substantially inert to said lead powder,
- wherein said lead powder forms permeable cages around said first powder particles, a plurality of said cages forming one of said aggregates,
- wherein C is at least about 100 .mu.m, and wherein C is much greater than a.
A method of forming a highly porous metal hydride composite comprises:
- (a) mixing together (1) first powder particles comprising at least one material selected from the group consisting of interstitial metal hydrides and interstitial metal hydride-formers, said first powder particles having an average largest dimension after initial activation by hydriding, a, and (2) second powder particles which are lead powder, wherein said first powder particles are separated from each other by said lead powder, wherein said first powder particles are substantially inert to said lead powder, and wherein said lead powder forms permeable cages around said first powder particles, so as to form a first mixture;
- (b) treating said first mixture so as to form a cohesive large aggregate mass;
- (c) breaking said large aggregate mass into pieces of aggregate;
- (d) arranging said pieces of aggregate in a random array so as to form a composite having large interconnected pores located between said pieces of aggregate,
- wherein said large interconnected pores have an average largest linear dimension, C, which is at least about 100 .mu.m and which is much greater than a.
A method for increasing the rate of hydriding of a metal hydride-former and increasing the rate of dehydriding of a ductile metal hydride comprises:
- (a) forming a composite by:
- (1) mixing together (1) first powder particles of at least one material selected from the group consisting of metal hydrides and metal hydride-formers with (2) second powder particles of at least one material selected from the group consisting of metals and plastics, so as to form a first mixture;
- (2) treating said first mixture so as to form a cohesive large aggregate mass;
- (3) breaking said large aggregate mass into pieces of aggregate;
- and
- (4) arranging said pieces of aggregate in a random array so that large interconnected pores exist between said pieces of aggregate, said pores having an average largest linear dimension C greater than about 100 .mu.m;
- and then
- (b) passing hydrogen gas through said composite in sufficient quantity to both (1) perform at least one function selected from the group consisting of hydriding and dehydriding said composite and (2) perform at least one function selected from the group consisting of supplying and removing by forced convection substantially all heat required for hydriding and for dehydriding.
A method for increasing the rate of hydriding of a metal hydride-former and increasing the rate of dehydriding of a ductile metal hydride comprises:
- (a) forming a composite by:
- (1) mixing together (i) first powder particles comprising at least one material selected from the group consisting of interstitial metal hydrides and interstitial metal hydride-formers and wherein said first powder particles have at least a partial coating of palladium metal thereon with (ii) second powder particles comprising at least one second material which is lead, so as to form a first mixture;
- (2) treating said first mixture so as to form a cohesive large aggregate mass;
- (3) breaking said large aggregate mass into pieces of aggregate;
- and
- (4) arranging said pieces of aggregate in a random array so that large interconnected pores exist between said pieces of aggregate, said pores having an average largest linear dimension C greater than about 100 .mu.m;
- and then
- (b) passing hydrogen gas through said composite in sufficient quantity to both (1) perform at least one function selected from the group consisting of hydriding and dehydriding said composite and (2) perform at least one function selected from the group consisting of supplying and removing by forced convection substantially all heat required for hydriding and for dehydriding,
- wherein said pieces of aggregate have a volume of inner void space between said pieces of aggregate which is within the range from about 20 to about 60% of the total volume occupied by said pieces of aggregate.
Dependencies are inferred from the claim text.