Density enhancement methods and compositions

Patent metadata

Field	Value
Publication number	US-2016368057-A1
Application number	US-201615071004-A
Country	US
Kind code	A1
Filing date	Mar 15, 2016
Priority date	Aug 20, 2013
Publication date	Dec 22, 2016
Grant date	—

Abstract

The present invention relates to granular composite density enhancement, and related methods and compositions. The application where the properties are valuable include but are not limited to: 1) additive manufacturing (“3D printing”) involving metallic, ceramic, cermet, polymer, plastic, or other dry or solvent-suspended powders or gels, 2) concrete materials, 3) solid propellant materials, 4) cermet materials, 5) granular armors, 6) glass-metal and glass-plastic mixtures, and 7) ceramics comprising (or manufactured using) granular composites.

First claim

1 . A method of making a granular composite composition, comprising:
a) providing at least first and second separate groups of at least 100 particles, each group possessing an average particle size V i avg and a passing curve, representative of a particle volume probability density function P i (V) of each group, the passing curve exhibiting one or more local maxima, and b) mixing particles from said at least first and second separate groups under conditions such that a combination of at least 50 particles from each group yields a combined granular composite exhibiting a combined passing curve, representative of a particle volume probability density function P(V) of the combination, wherein said combined granular composite has the following features:
i. the combined passing curve exhibits at least two local maxima, a first maximum occurring at a smaller volume (point) V i and a second maximum occurring at a larger volume (point) V 2 , associated with different particle groups “1” and “2” such that a ratio of V 2 avg /V 1 avg is less than or equal to 10,000, where an average particle size V i avg for any group of particles is defined as integral of V*P i (V) (or equivalent summation) taken over all particles in the group;
ii. the combined passing curve exhibits at least one local minimum falling between the at least two local maxima such that a height of a passing curve at the local minimum is no more than 75% of a height of a passing curve at either local maxima; and
iii. two points V 1 and V r on a plot representing a combined passing curve, wherein V r /V 1 =10,000, such that integral of V*P(V) from V 1 to at least one of the local minima falling between the two local maxima is at least 2% of integral of V*P(V) from V 1 to V r , and such that integral from the at least one local minimum to V r is at least 2% of integral of V*P(V) from V 1 to V r .

2 . The method of claim 1 , wherein said mixing is done under conditions which inhibit phase separation.

3 . The method of claim 1 , wherein said combined composite exhibits a porosity, equal to one minus tap density, of less than 25%.

4 . The method of claim 1 , wherein said mixing reduces viscosity, or relative viscosity of the combined granular composite immersed in a solvent, a paste, a gel, a liquid, or a suspension, as compared to unmixed particles individually at comparable loading.

5 . The method of claim 1 , wherein at least two (labeled ‘1’ and “2”) of the potentially more than two mixed particle groups satisfy V 2 avg /V 1 avg <=2,000 and >=25.

6 . The method of claim 1 , wherein said mixing is in a container with a diameter and height at least 100 times larger than the average particle size of each of the at least first and second separate groups.

7 . The method of claim 5 , wherein said mixing of two groups of particles results in a final volume fraction of particles from the group with average particle size V 1 avg of 10-80%.

8 . The method of claim 1 , wherein at least one volume probability density function P i (V) among the groups exhibits an arithmetic standard deviation of less than 100%.

9 . A granular composite made by the method of claim 1 having a final porosity of less than 25%.

10 . A method of making concrete comprising mixing the granular composite of claim 9 with a liquid or a suspension.

11 . A method of laser sintering comprising sintering the granular composite of claim 9 with a laser.

12 . A method of laser melting comprising melting the granular composite of claim 9 with a laser.

13 . A method of additive manufacturing of ceramics comprising forming a ceramic with the granular composite of claim 9 as a powder or a suspension.

14 . A method of powder metallurgy comprising forming a structure with the granular composite of claim 9 as a powder or a suspension.

15 . A method of injection molding comprising injecting the granular composite of claim 9 as a powder or a suspension into a mold.

16 . A method of producing granular armors comprising preparing a granular armor with the granular composite of claim 9 as a powder or a suspension.

17 . The method of claim 1 , where the first and second separate particle groups are divided into subsets and combined to yield a low-porosity combined composite.

18 . A granular composite composition, comprising at least 100 particles, the granular composite composition exhibiting a passing curve representative of a particle volume probability density function P(V) of the at least 100 particles, the passing curve having the following features:
a) at least two local maxima occurring at points V i and V j , where V i <V j , and having at least one local minimum V i−f between V 1 and V j , such that a height of the passing curve at the local minimum is no more than 75% percent of the height of the passing curve at either of the two local maxima; b) average particle volumes V i avg and V j avg such that V j avg /V i avg ≦10,000, of particle groups “i” and “j” where an average particle size V i avg for any group of particles is defined as the integral of V*P i (V) (or the equivalent summation) taken over all particles in the group, where group “i” is a group containing all particles with volumes ranging from V h−i to V i−j including V i , and group “j” is a group containing all particles with volumes ranging from V i−j to V j−k including V j , and where V h−i is the larger of either a volume of a smallest particle in the composite or a minimum between maxima at points V h and V i , V h <V i , such that, a maximum at V h corresponds to another particle group “h” and where a point V j−k is a smaller than either a volume of a largest particle in the composite, or a minimum between maxima at V j and V k , V j <V k , such that V k corresponds to another particle group “k”; and c) V 1 and V r , V r /V 1 =10,000, such that integral of V*P(V) from V h−i to at least one of the local minima V i−j falling between the maxima at V i and V j is at least 2% of integral of V*P(V) from V 1 to V r , and such that integral from that same local minimum at V i−j to V j−k is at least 2% of integral of V*P(V) from V 1 to V r .

19 . The composition of claim 18 , wherein for at least one pair of particle groups “j” and “i”, V j avg >V i avg and V j avg /V i avg <=2,000 and >=25.

20 . The composition of claim 18 , wherein for at least one pair of particle groups adjacent by average volume, an average number of large-large nearest neighbors within a larger of the two groups by average volume is greater than or equal to one.

21 . The composition of claim 18 , wherein a relative volume of a smaller of at least one pair of particle groups adjacent by average volume is between 10% and 80% of a total volume of particles in the two adjacent groups.

22 . The composition of claim 18 , wherein a mixture of particle groups in fixed amounts occupies a larger volume of space than a volume of space occupied by any single particle group in its fixed amount on its own.

23 . The composition of claim 18 , wherein said granular composite exhibits a porosity of less than 25%.

24 . The composition of claim 18 , wherein said granular composite is immersed in a solvent, a paste, a gel, a liquid, or a suspension.

25 . The composition of claim 18 , wherein spatial phase separation of particles into groups does not occur for all groups of particles.

Assignees

• Hopkins Adam Bayne
• Univ Princeton

Inventors

• Hopkins Adam Bayne
• Torquato Salvatore

Classifications

• B29C64/371

  using an environment other than air, e.g. inert gas · CPC title

• B29C64/268

  using laser beams; using electron beams [EB] · CPC title

• C04B35/111 Primary

  Fine ceramics · CPC title

• B22F1/052

  characterised by a mixture of particles of different sizes or by the particle size distribution · CPC title

• B22F1/065

  Spherical particles · CPC title