WO2019191541A1 - Matériau particulaire et son procédé de formation - Google Patents

Matériau particulaire et son procédé de formation Download PDF

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Publication number
WO2019191541A1
WO2019191541A1 PCT/US2019/024759 US2019024759W WO2019191541A1 WO 2019191541 A1 WO2019191541 A1 WO 2019191541A1 US 2019024759 W US2019024759 W US 2019024759W WO 2019191541 A1 WO2019191541 A1 WO 2019191541A1
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WIPO (PCT)
Prior art keywords
phase
particulate material
vol
microns
boron nitride
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Application number
PCT/US2019/024759
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English (en)
Inventor
David E. Woolley
Nabil Nahas
Sarah Elizabeth PLAIN
Original Assignee
Saint-Gobain Ceramics & Plastics, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by Saint-Gobain Ceramics & Plastics, Inc. filed Critical Saint-Gobain Ceramics & Plastics, Inc.
Publication of WO2019191541A1 publication Critical patent/WO2019191541A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
    • C09K5/08—Materials not undergoing a change of physical state when used
    • C09K5/14—Solid materials, e.g. powdery or granular

Definitions

  • the following is directed to particulate material, and particularly, a particulate material including a first phase and a second phase.
  • a method for forming a particulate material comprises heating a first phase comprising boron nitride to form an intermediate body having at least a portion of the boron nitride particles bonded to each other within the intermediate body, infiltrating a porosity of the intermediate body with a second phase to form a body having a Normalized Thermal Conductivity of at least 0.01 Wcm 2 /g-K.
  • a particulate material in another aspect, includes a body having a Normalized Thermal Conductivity of at least 0.01 Wcm /g-K, a first phase including boron nitride particles, wherein at least a portion of the boron nitride particles are bonded to each other, and a second phase comprising an organic material contained within pores of the body.
  • a particulate material comprises a body including a first phase including boron nitride particles having an average contact length of at least 0.08 microns, and a second phase comprising an organic material contained within pores of the body.
  • a particulate material may have a body including a first phase including boron nitride particles, wherein at least 25% of the boron nitride particles are in direct contact with each other, and a second phase comprising an organic material contained within pores of the body.
  • FIG. 1 includes a flow chart of a process for forming a particulate material according to an embodiment.
  • FIG. 2 includes a cross-sectional illustration of a particulate material according to an embodiment.
  • FIG. 3 includes a cross-sectional illustration of a thermal management article including the particulate material according to an embodiment.
  • FIG. 4A includes a cross-sectional scanning electron microscope image of a particulate material including a boron nitride particles mixed with an organic material as provided in Comparative Example.
  • FIG. 4B includes a black and white image of FIG. 4A.
  • FIG. 5 includes a cross-sectional scanning electron microscope image of a particulate material including boron nitride particles infiltrated with an organic material as provided in Sample 1 and in accordance with an embodiment.
  • FIG. 6 includes a cross-sectional scanning electron microscope image of a particulate material including particles of a first phase infiltrated with an organic material used to measure the average contact length of the particles of the first phase.
  • FIGs. 7A and 7B include SEM images of a portion of a particulate material used for measuring dimensions of the polycrystalline particles.
  • the following is directed to a method of creating a particulate material, aspects of the particulate material, and thermal management articles incorporating the particulate material.
  • FIG. 1 includes a flow chart providing certain steps for forming the particulate material.
  • the process for forming a particulate material can include heating a first phase to form an intermediate body at step 101.
  • other processes may optionally precede heating.
  • the process can start with obtaining a raw material of the first phase, such as a particulate material including boron nitride.
  • the raw material particulate may be selected and processed to obtain a material with a select particle size distribution, shape, and composition.
  • the raw material particulate may be sourced from a vendor.
  • the raw material particulate may be created through one or more processes, including for example, but not limited to spray drying, which may facilitate creation of discrete raw material particles having a targeted size, shape, porosity, and composition. It will be appreciated that one may also use a combination of sourcing a raw material particulate and then processing the sourced raw material particulate to refine the size, shape, porosity, and composition.
  • the raw material particulate may consist essentially of the first phase, and more particularly, may consist essentially of boron nitride. In such a processing pathway, the raw material particulate may be heated as discrete particles to form an intermediate body that is in the form of a plurality of discrete particles.
  • Yet another optional process that may be utilized prior to heating can include mixing the raw material particulate of the first phase and/or shaping of the raw material particulate into a monolithic green body.
  • Mixing may be conducted using processes in the art.
  • Some suitable shaping processes can include, but is not limited to, pressing, molding, casting, punching, cutting, depositing, extruding, drying (e.g., freeze drying), or any combination thereof.
  • the monolithic green body may be formed to include some controlled content and size of porosity.
  • the monolithic green body may consist essentially of the first phase comprising boron nitride, and more particularly, may consist essentially of boron nitride.
  • Heating may be conducted on the monolithic green body to form an intermediate body, such that the monolithic intermediate body has substantially the same shape and size as the monolithic green body.
  • the process of heating can be conducted at a sintering temperature.
  • the sintering temperature may be within a range of at least l500°C to not greater than 2500°C.
  • the sintering temperature may be at least l600°C, such as at least l700°C or at least 1800 °C or at least l900°C see or even at least 2000°C.
  • the sintering temperature may be not greater than 2400°C, such as not greater than 2300°C or even not greater than 2200°C. It will be appreciated that the sintering temperature can be within range including any of the minimum and maximum values noted above.
  • Heating can be conducted in a non-oxidizing atmosphere, such as an inert or reducing atmosphere having a partial pressure of oxygen below 10 Pa or even below 1 Pa.
  • the process of heating can include bonding at least a portion of the boron nitride particles to each other within the intermediate body.
  • bonding can include joining at least a portion of the boron nitride particles to each other within the first phase. Bonding may not include simple contact between adjacent particles, but a fusing of adjacent particles to each other. In one particular embodiment, at least a portion of the boron nitride particles are sinter- bonded to each other within the intermediate body.
  • the process can continue at step 102 by infiltrating a porosity of the intermediate body with a second phase to form a body.
  • the second phase may include an organic material. Further details on the composition of the second phase are described herein.
  • the intermediate body may have various possible shapes, including but not limited to, a monolithic body of a certain type and content porosity or discrete particles each having a certain type and content of porosity.
  • the porosity of the intermediate body may be of a certain type and content suitable for infiltration by the second phase.
  • the intermediate body may have a porosity of at least 10 vol% for the total volume of the intermediate body, such as at least 25% vol% or at least 30 vol% or at least 40 vol% or at least 50 vol% or at least 60 vol% or at least 70 vol% or at least 80 vol%.
  • the porosity of the intermediate body may be not greater than 90 vol% for a total volume of the intermediate body, such as not greater than 80 vol% or not greater than 70 vol% or not greater than 60 vol% or not greater than 50 vol% or not greater than 40 vol% or not greater than 30 vol% or not greater than 20 vol%. It will be appreciated that the porosity of the intermediate body can be within a range including any of the minimum and maximum values noted above.
  • infiltration may include mixing the intermediate body with the second phase to infiltrate the porosity of the intermediate body with the second phase.
  • the intermediate body may be in the form of discrete particles that may be mixed within the second phase to facilitate infiltration of the second phase into the porosity of each of the discrete particles.
  • the process of infiltrating can include immersing the intermediate body in the second phase to infiltrate the porosity of the intermediate body with the second phase.
  • the process of immersing may be suitable for an intermediate body that is a monolithic body.
  • the process of infiltrating may further include applying a pressure differential to the intermediate body.
  • the application of a pressure differential may apply suitable force on the second phase to facilitate infiltration of the second phase into the porosity of the intermediate body.
  • infiltrating may include contacting at least a portion of the intermediate body with the second phase and reducing the pressure in the environment containing the intermediate body and the second phase to encourage the second phase to infiltrate the porosity of the intermediate body.
  • the process may further include curing the infiltrated body. Curing may cause cross
  • curing may be accomplished by the application of heat, radiation, additives, or any combination thereof.
  • curing may be accomplished via heating to a curing temperature to cure at least a portion of the second phase.
  • a suitable curing temperature may be within a range of at least 30°C to not greater than 200° C.
  • the curing temperature may be held for a particular duration noted as the curing duration.
  • a suitable curing duration may be within a range of at least one minute to not greater than two hours.
  • curing may include application of radiation to the infiltrated body.
  • the process may further include crushing of the infiltrated body to form a particulate material.
  • the crushing process may be optional, particularly for those processing pathways wherein the intermediate body is in the form of discrete particles.
  • the resulting infiltrated monolithic body may be formed into discrete particles via a crushing process. Any suitable crushing process may be utilized.
  • the process may further include an optional sorting process to create a batch of particulate material having the desired particle size distribution and shape distribution.
  • Sieving is a method that may be used to obtain a batch of particulate having the desired particle size distribution. Any suitable sieving and sorting process may be used.
  • Other optional processes may include the addition and/or functionalization of coupling agents, including for example, but not limited to, alkoxides, silanes, siloxanes or any combination thereof.
  • An illustration of an embodiment of a particulate material can be seen in FIG. 2.
  • the particulate material 200 can be an agglomerate of boron nitride particles (202), also called the first phase herein, which are sinter-bonded to each other and form a polycrystalline network.
  • a resin material (second phase) 203 has been infiltrated in the openings (also called herein pores) of the boron nitride network structure.
  • the particulate may have a certain average particle size suitable for use in a given application.
  • the particulate material can have an average particles size within a range of at least 10 microns and not greater than 300 microns, such as within a range including at least 40 microns to not greater than 250 microns or within a range including at least 40 microns and not greater than 200 microns or within a range including at least 50 microns and not greater than 150 microns or within a range including at least 60 microns and not greater than 120 microns.
  • the particulate material may have a certain maximum particle size making it suitable for use in certain applications.
  • the particulate material can have a maximum particles size within a range of at least 10 microns and not greater than 1000 microns.
  • the particulate material can have a maximum particle size of not greater than 900 microns or not greater than 800 microns or not greater than 700 microns or not greater than 600 microns or not greater than 500 microns or not greater than 400 microns or not greater than 300 microns or not greater than 200 microns or not greater than 150 microns or not greater than 100 microns or not greater than 70 microns.
  • the maximum particle size of the particulate material can be at least 15 microns or at least 20 microns or at least 25 microns or at least 50 microns or at least 100 microns or at last 200 microns. It will be appreciated that the maximum particle size of the particulate material can be within a range including any of the minimum and maximum values noted above.
  • the average particle size and maximum particle size of the particulate material can be evaluated by sieve analysis or Laser particle size distribution in dry or wet conditions, such as a Horiba LPS device.
  • the resulting particulate material may have certain characteristics suitable for use in various applications, including but not limited to, thermal management articles.
  • the particulate material may include a first phase including boron nitride particles, wherein at least a portion of the boron nitride particles are bonded to each other and a second phase comprising an organic material contained within the pores of the body.
  • the first phase may include a material that prides suitable characteristics to facilitate the use of the particulate material in thermal management articles.
  • the first phase can include boron nitride, and more particularly, hexagonal boron nitride.
  • the first phase can include a majority content of boron nitride, such as at least 60 vol% boron nitride for a total volume of the first phase, or at least 70 vol% or at least 80 vol% or at least 90 vol% or at least 95 vol% or at least 99 vol% boron nitride for a total volume of the body.
  • the first phase may include not greater than 99.99 vol% boron nitride, or not greater than 99.95 vol%, such as not greater than 99 vol% boron nitride for total volume of the first phase. It will be appreciated that the first phase can include a content of boron nitride within a range including any of the minimum and maximum values noted above. According to one particular embodiment, the first phase may consist essentially of hexagonal boron nitride.
  • the body may have limited contents of certain species, which may be undesirable depending upon the intended use of the particulate material.
  • the body may have a particular content of boron oxide (B 2 0 3 ), such as not greater than 1 wt% boron oxide for a total weight of the body, such as not greater than 0.9 wt% or not greater than 0.8 wt% or not greater than 0.7 wt% or not greater than 0.6 wt% or not greater than 0.5 wt%.
  • B 2 0 3 boron oxide
  • the particulate material may include a minimum content of calcium (Ca), such as not greater than 1 wt% calcium for a total weight of the body or not greater than 0.1 wt% or not greater than 0.01 wt% or even not greater than 0.001 wt% calcium for a total weight of the body.
  • the body may contain minimal content of alkali -containing species.
  • the body of the particulate material may have not greater than 1 wt% alkali-containing species for a total weight of the body, or not greater than 0.1 wt% or not greater than 0.01 wt% or not greater than 0.001 wt% of an alkali -containing species for total weight of the body.
  • the particulate material may be formed such that the body has a certain content of the first phase relative to the total volume of the body, which may facilitate improved performance of the particulate.
  • the body may include at least 10 vol% of the first phase the total on the body, such as at least 12 vol% or at least 15 vol% or at least 20 vol% or at least 25 vol% or at least 30 vol% or at least 35 vol% or at least 40 vol% or at least 45 vol% or at least 50 vol% or at least 55 vol% or at least 60 vol% or at least 65 vol% or at least 70 vol% or at least 75 vol% for a total volume of the body.
  • the body may include not greater than 80 vol% of the first phase for total volume of the body, such as not greater than 75 vol% or not greater than 70 vol% or not greater than 65 vol% or not greater than 60 vol% or not greater than 55 vol% or not greater than 50 vol% or not greater than 45 vol% or not greater than 40 vol% or not greater than 35 vol% or not greater than 30 vol% or not greater than 25 vol% or not greater than 20 vol% or not greater than 15 vol%.
  • the body may include a content of the first phase within a range including any of the minimum and maximum values noted above, including but not limited to, within a range of at least 10 vol% and not greater than 80 vol% for a total volume of body, such as within a range of at least 25% and not greater than 70 vol% or within a range of at least 30 vol% and not greater than 60 vol% or within a range including at least 35 vol% and not greater than 55 vol% or even within a range including at least 35 vol% percent and not greater than 50 vol% of the first phase for a total volume of the body.
  • the boron nitride particles contained within the first phase may be a crystalline material, and more specifically, a monocrystalline or polycrystalline material.
  • the material of the first phase may include a material that is formed of a plurality of grains (i.e. crystallites), wherein the crystallites define domains of single crystalline material.
  • the crystallites of the boron nitride particles contained within the body of the particulate material may be formed to have an average length within a range between 0.2 microns and not greater than 50 microns.
  • the first phase can include a network of crystalline (i.e. monocrystalline and/or polycrystalline) particles.
  • the crystalline particles can include boron nitride particles bonded to each other, which may result in a crystalline network extending through at least a portion of the first phase.
  • the boron nitride particles of the first phase can have a platelet shape.
  • the first phase may include other materials, including, but not limited to, other inorganic materials, such as oxides, carbides, nitrides, borides, silicon-containing compositions, or any combination thereof.
  • the bonding of the boron nitride particles to form a crystalline network may facilitate improved thermally conductive pathways for heat to flow through the particle.
  • the crystalline particles of the first phase may have an average length within a range of at least 0.2 microns and not greater than 50 microns, such as within a range including at least 1 micron to not greater than 40 microns or within a range including at least 2 microns and not greater than 30 microns or within a range including at least 3 microns and not greater than 20 microns or within a range including at least 5 microns and not greater than 10 microns.
  • the boron nitride particles of the first phase can have the same length as provided above for the crystalline particles of the first phase.
  • the boron nitride particles can have an average length within a range of at least 0.2 microns and not greater than 50 microns, such as within a range including at least 1 micron to not greater than 40 microns or within a range including at least 2 microns and not greater than 30 microns or within a range including at least 3 microns and not greater than 20 microns or within a range including at least 5 microns and not greater than 10 microns.
  • the crystalline particulate of the first phase may have a particular thickness within a range of at least 0.1 microns to not greater than 5 microns.
  • the born nitride particles may have an average thickness or within a range including at least 0.5 microns to not greater than 4 microns or within a range including at least 0.8 microns and not greater than 4 microns or within a range including at least 1 micron and not greater than 4 microns or within a range including at least 1 microns and not greater than 3 microns.
  • the first phase may include platelet- shaped particles having a length, width, and thickness, wherein length>width>thickness. More specifically, the boron nitride particles of the first phase may include platelet -shaped particles having a length, width, and thickness, wherein length>width>thickness. In one embodiment, the particles of the first phase may have a particular shape defining a primary aspect ratio of length: thickness of at least 1:1 or at least 1.2:1 or at least 1.5:1 or at least 2:1 or at least 2.5:1 or at least 3:1 or at least 4: 1 or at least 5:1 or at least 10: 1.
  • the primary aspect ratio can be not greater than 50:1 or not greater than 30: 1 or not greater than 20:1 or not greater than 10:1 or not greater than 5 : 1 or not greater than 2: 1 or not greater than 1:1.
  • the primary aspect ratio of the first phase e.g., boron nitride particles
  • the primary aspect ratio can be evaluated using scanning electron microscope (SEM) images, such as shown in FIGs. 7A and 7B. The same sample preparation method as described herein for FIG. 7B may be used to obtain suitable SEM images for evaluating the primary aspect ratio.
  • the particulate may have a particular percentage of the boron nitride particles bonded to each other, which may facilitate improved performance of the particulate. That is, a certain minimum content of the boron nitride particles may be bonded to each other, and more particularly sinter-bonded to each other. For example, at least 25% of the boron nitride particles may be sinter-bonded to each other, such as at least 30% or at least 40% or at least 50% or at least 60% or at least 70% or at least 80% or at least 90%. Still another non limiting embodiment, not greater than 99% of the boron nitride particles of the first phase may be sinter-bonded to each other.
  • the content of boron nitride particles sinter- bonded to each other can be within a range between any of the minimum and maximum values noted above, including but not limited to, within a range of at least 25% and not greater than 99%, or within a range of at least 30% and not greater than 99%, or even within a range of at least 50% and not greater than 99% of the boron nitride particles within the first phase.
  • the boron nitride particles define a sintered polycrystalline network, wherein the boron nitride particles that are fused to each other and form a network extending throughout at least a portion of the body.
  • the creation of a particulate material having a body wherein a portion of the first phase comprising boron nitride particles are bonded to each other provides a suitable pathway for heat to move through the body of the particle, which may result in a body having improved thermal conductivity characteristics.
  • the body of the particulate material may have a certain Normalized Thermal Conductivity that can facilitate suitable transfer of heat through the body of the particle.
  • the body may have a Normalized Thermal Conductivity of at least 0.01 Wcm 2 /g-K, such as least 0.011 Wcm 2 /g-K or as least 0.012 Wcm 2 /g- K or at least 0.013 Wcm 2 /g-K or at least 0.014 Wcm 2 /g-K or at least 0.015 Wcm 2 /g-K or at least 0.016 Wcm 2 /g-K or at least 0.02 Wcm 2 /g ⁇ K or at least 0.022 Wcm 2 /g ⁇ K or at least 0.025 Wcm 2 /g ⁇ K or at least
  • the body may have a Normalized Thermal
  • the body can have a Normalized Thermal Conductivity within a range including any of the minimum and maximum values noted above, including for 2 example, a Normalized Thermal Conductivity within a range of at least 0.01 Wcm /g-K to not greater than 0.3 Wcm 2 / g-K, such as within a range including at least 0.012 Wcm 2 / g-K and not greater than 0.2 Wcm 2 / g-K, such as within a range including at least 0.015 Wcm 2 /g-K to not greater than 0.2 Wcm /g- K or within a range of at least 0.015 Wcm /g- K to not greater than 0.1 Wcm /g-K or even within range including at least 0.015 Wcm /g-K to not greater than 0.05 Wcm 2 /g-K.
  • the Normalized Thermal Conductivity of a body of a particulate material is measured according to the following test and analysis.
  • a composite body is formed using particulate material having an average particle size of approximately 115 to 130 microns that is mixed with silicone having a density (D sii ) of 0.97 g/cm , such as TSE3033commercially available from Momentive Performance Materials.
  • the silicone includes parts A and B that are mixed in equal quantity by weight.
  • ) is measured by Hg porosimetry (i.e.,“total intrusion volume” at 1 psi in Hg porosimetry) according to standard ISO 15901-1, and expressed in cm /g.
  • the mixture is formed to include 40 vol% of the particulate material and 60 vol% of the silicone based on the sum of the volume of the particulate material and the silicone. For each example, the weight of silicone oil per weight of particulate material equals TPVp*D sii .
  • the mixture is shaped via casting a film having a thickness of 5 mm and cured at 80°C for a duration of 4 hours.
  • the particulate material may have a certain microstructure, which may facilitate improved performance.
  • the first phase may have an average contact length of at least 0.08 microns, wherein average contact length is a characteristic defining the average contact length between two adjacent particles of the first phase as described in more detail below.
  • the average contact length of the first phase may be greater, such as least 0.09 microns or at least 0.1 microns or at least 0.11 microns or at least 0.12 microns or at least 0.13 microns or at least 0.14 microns or at least 0.15 microns or at least 0.16 microns or at least 0.17 microns or at least 0.18 microns or at least 0.19 microns or at least 0.2 microns.
  • the average contact length maybe not greater than 5 microns, such as not greater than 3 microns or not greater than 2 microns. It will be appreciated that the average contact length of the first phase may be within a range including any of the minimum and maximum values noted above.
  • the average contact length is measured by providing a suitable amount (e.g., 1 gram) of particulate material mounted in epoxy and prepared as one or more polished samples. At least five randomly selected scanning electron microscope images are taken of at least five randomly selected particulates. The images are taken at a magnification that is suitable for evaluating the contact between particles of the first phase (e.g., boron nitride particles), such as a magnification of 2500X as provided in FIG. 5. The image may be cropped to obtain a suitable number of particles for measurement.
  • a suitable amount e.g., 1 gram
  • At least five randomly selected scanning electron microscope images are taken of at least five randomly selected particulates.
  • the images are taken at a magnification that is suitable for evaluating the contact between particles of the first phase (e.g., boron nitride particles), such as a magnification of 2500X as provided in FIG. 5.
  • the image may be cropped to obtain a suitable number of particles for measurement.
  • a binary image i.e., only black and white
  • a binary image can be created by choosing an appropriate threshold gray scale value that distinguishes black and white and clearly delineates the edges of the particles from the back ground (i.e., epoxy).
  • Imaging software such as Image J l.48v may be used including the functions of “smooth” and“despeckle” to improve the binary image and assist with separating the particles of the first phase from the mounting epoxy.
  • Using a line tool function in Image J l.48v the contact length of those particles of the first phase in contact with each other is measured.
  • a suitable exemplary image is provided in FIG. 6. The measured values are used to calculate the average contact length.
  • the first phase may have a at least a minimum percentage of boron nitride particles that are in direct contact with each other, which may facilitate improved characteristics of the particulate material.
  • at least 25% of the boron nitride particles of the first phase may be in contact with each other such at least 27% or at least 30% or at least 33% or at least 35% or at least 37% or at least 40% or at least 43% or at least 45% or at least 47% or at least 50% or at least 52% or at least 55% or at least 57% or at least 60% or at least 62% or at least 65% or at least 67% or at least 70% or at least 72% or at least 75% or at least 77% or at least 80% or at least 82% or at least 85% or at least 87% or at least 90% or at least 92% or at least 95%.
  • not greater than 99% of the boron nitride particles may be in direct contact with each other, such as not greater than 95% or not greater than 92% or not greater than 90% or not greater than 87% or not greater than 85% or not greater than 82% or not greater than 80% or not greater than 77% or not greater than 75% or not greater than 72% or not greater than 70% or not greater than 67% or not greater than 65% or not greater than 62% or not greater than 60% or not greater than 57% or not greater than 55% or not greater than 52% or not greater than 50% or not greater than 47% or not greater than 45% or not greater than 42% or not greater than 40% or not greater than 37% or not greater than 35% or not greater than 32% or not greater than 30% or not greater than 27%.
  • the percentage of boron nitride particles that are in direct contact with each other within the body of the particulate material may be within a range including any of the minimum and maximum values noted above. It will be understood that the percentage of boron nitride particles in contact with each other can be an average percentage based on measurements from a suitable sample of randomly selected particulates.
  • the percentage of boron nitride particles in direct contact with each other is evaluated using the same imaging technique as used to evaluate the average contact length. Specifically, samples are mounted as described above and images are taken at a magnification that is suitable for evaluating the contact between particles of the first phase (e.g., boron nitride particles), such as a magnification of 2500X as provided in FIGs. 4 and 5. After obtaining a suitable image, a binary image (i.e., only black and white) can be created by choosing an appropriate threshold gray scale value that distinguishes black and white and clearly delineates the edges of the particles from the back ground (i.e., epoxy).
  • a binary image i.e., only black and white
  • Imaging software such as ImageJ l.48v may be used including the functions of“smooth” and“despeckle” to improve the binary image and assist with separating the particles of the first phase from the mounting epoxy.
  • the total number of particles of the first phase is counted in the image, excluding those that are cropped by the edge of the image.
  • the total number of isolated particles of the first phase is also counted wherein isolated particles are those that are not in contact with any adjacent particles.
  • the percentage of boron nitride particles in contact with each other is evaluated by dividing the total number of boron nitride particles in contact with each other by the total number of boron nitride particles in the image.
  • the particulate material may have a certain minimum content of the first phase present at the exterior surface, such that the first phase intersects with the exterior surface and defines a portion of the exterior surface of the body. It is theorized that maintaining a certain minimum content of the first phase at the exterior surface of the particles may facilitate movement of heat between particles that are abutting each other, particularly when at least a portion of the interface between the abutting particles includes the first phase.
  • the particulate material can include a body having at least 5% of the exterior surface of the body including the first phase, such at least 8% of the exterior surface of the body comprising the first phase or at least 10% or at least 12% or at least 15% or at least 18% or at least 20% or at least 22% or at least 25% or at least 27% or at least 30% or at least 33% or at least 35% or at least 37% or at least 40% or at least 42% or at least 45% or at least 47% or at least 50% or at least 53% or at least 55% or at least 57% or at least 60% or at least 62% or at least 65% or at least 67% or at least 70% or at least 73% or at least 75% or at least 77% or at least 80% or at least 85%. Still in another non-limiting embodiment, not greater than 99% of the exterior surface of the body may include the first phase, such as not greater than 95% or not greater than 93% or not greater than 90% or not greater than 87% or not greater than
  • the content of the first phase of the exterior surface of the body may be within range including any of the minimum and maximum values noted above, including for example, but not limited to, within a range of at least 5% and not greater than 99% or within a range including at least 10% and not greater than 90% or within range of at least 20% and not greater than 80% or within a range including at least 30% and not greater than 60% or within a range including at least 30% and not greater than 50% of the exterior surface of the body including the first phase.
  • the percentage of the first phase present at the exterior surface of the particulate material may be evaluated using SEM images.
  • the mounting and imaging techniques may be the same as described above for evaluating the average contact length.
  • samples are mounted as described above and images are taken at a magnification that is suitable for evaluating the contact between particles of the first phase (e.g., boron nitride particles), such as a magnification of 2500X as provided in FIGs. 4 and 5.
  • a binary image i.e., only black and white
  • Imaging software such as ImageJ l.48v may be used including the functions of“smooth” and“despeckle” to improve the binary image and assist with separating the particles of the first phase from the mounting epoxy.
  • the total number of particles of the first phase intersecting the exterior surface of the particulate can be compared to the total number of particles of the first phase contained in the particle.
  • the percentage of particles of the first phase intersecting the exterior surface of the particulate can be calculated by dividing the number of particles of the first phase by the total number of particles of the first phase contained in the particulate and multiplying by 100%.
  • all measurements herein can be an average value based upon measurement of a suitable sample size to obtain a statistically relevant data set.
  • the Normalized Thermal Conductivity can be an average value based upon a suitable number of measurements to calculate a statistically relevant average value.
  • the features of average length, average width, and average thickness of the first phase can also be based upon multiple measurements of a suitable sample size on a plurality of randomly selected particles.
  • features such as the average contact length, percentage of boron nitride particles in contact with each other, and the percentage of the first phase at the exterior surface can be average values based upon measurements made on randomly selected samples, wherein the sample size is of a sufficient number to generate statistically relevant information.
  • a suitable sample size can include at least 5 measurements on randomly selected objects, or at least 10 or at least 15 or at least 20 measurements on randomly selected objects.
  • any feature of the particulate, body, first phase or second phase can be reference to a plurality.
  • a claim directed to a particulate material having a certain feature can also be interpreted as a claim to the same feature for a plurality of particulates.
  • the Normalized Thermal Conductivity may be relevant to a single particulate material or a plurality of particulate material.
  • the second phase can include an organic material.
  • the organic material may be specifically selected such that it properly infiltrates the intermediate body and further provides the desired mechanical, chemical, and thermal characteristics in the finally-formed particulate material.
  • the second phase may include a thermoset, thermoplastic, or any combination thereof.
  • the second phase may consist essentially of an organic material, such as a thermoset organic material.
  • the organic material of the second phase may include a material selected from the group of epoxies, polyacrylics, polyvinyls, polyesters, polyurethanes, phenolics, furans, ureas, formaldehydes, melamines, phthalates, benzoxazines, polyimides, polyamides, silicones, thiols, or any combination thereof.
  • the second phase may consist essentially of any one of polyacrylics, polyvinyls, polyesters, polyurethanes, phenolics, furans, ureas, formaldehydes, melamines, phthalates, benzoxazines, polyimides, polyamides, silicones, thiols, or any combination thereof.
  • the second phase may consist essentially of one of a silicone resin, epoxy resin, phenol formaldehyde, bismaleimide, cyanate ester, phenolic resin, or any combination thereof.
  • the second phase may include a certain content of organic material that may facilitate improved formation and characteristics of the particulate material.
  • second phase may include at least 50 vol% of a thermoset material for an entire volume of the second phase, such as lease 60 vol% or at least 70 vol% or at least 80 vol% or at least 90 vol% or at least 95 vol% of a thermoset for an entire volume of the second phase.
  • the second phase may consist essentially of a thermoset material.
  • the second phase may include not greater than 99 vol% of a thermoset material, such as not greater than 95 vol% or not greater than 90 vol%. It will be appreciated that the second phase can include a content of a thermoset material within a range including any of the minimum and maximum values noted above.
  • the body may include a particular content of the second phase that may facilitate improved formation and characteristics of the particulate material.
  • the body may include at least 10 vol% of second phase for a total volume of body or at least 12 vol% or at least 15 vol% or at least 20 vol% or at least 25 vol% or at least 30 vol% or at least 35 vol% or at least 40 vol% or at least 45 vol% or at least 50 vol% or at least 55 vol% or at least 60 vol% or at least 65 vol% or at least 70 vol% or at least 75 vol% for a total volume of the body.
  • the body may include not greater than 85% of the second phase for a total volume of the body, such as not to 75 vol% or not greater than 70 vol% or not greater than 65 vol% or not greater than 60 vol% or not greater than 55 vol% or not greater than 50 vol% or not greater than 45 vol% or not greater than 40 vol% or not greater than 35 vol% or not greater than 30 vol% or not greater than 25 vol% or not greater than 20 vol% or not greater than 15 vol%.
  • the content of the second phase in the body may be within a range including any of the minimum and maximum percentages noted above, including but not limited to, within a range of at least 10 vol% and not greater than 80 vol% or within a range including at least 20 vol% and not greater than 75% or within range including at least three vol% and not 60 vol% of the second phase for total volume of body
  • the body may consist essentially of the first phase of the second phase.
  • the body can include only the first phase and the second phase and may include minimal or trace amounts of other materials that do not substantially affect the characteristics of the particulate material.
  • the second phase can include a material having a certain hardness, such as a Rockwell R hardness of at least 100 or at least 110 or at least 120 or at least 130 or at least 140 or at least 150. Still, in one non-limiting embodiment, the Rockwell R hardness can be not greater than 200 or not greater than 180 or not greater than 150.
  • the Izod impact strength can be not greater than 1 ft-lb/in or not greater than 0.8 ft- lb/in or not greater than 0.6 ft-lb/in or not greater than 0.4 ft-lb/in.
  • the second phase may have a particular water absorption of not greater than 0.5% according to ASTM D570 standard, such as not greater than 0.3% or not greater than 0.2%.
  • the second phase may have a particular flammability, such as a flammability of V-0 according to UL94 standard.
  • one or more optional additives may be incorporated into the body of the particulate material.
  • the one or more additives may be contained within the second phase.
  • some suitable examples of additives can include an inorganic material, such as a ceramic, glass, metal, or a metal alloy. More particularly, the additive may include an oxide, carbide, nitride, boride, or any combination thereof.
  • the additive may include a composition including at least one element from the group consisting of an alkali element, alkali earth element, a transition metal element, a lanthanide, a chalcogenide, a halogen, or any combination thereof.
  • the additives may be included within the body for certain functionality, including for example, an additive may be a pigment to provide color to the body of the particulate material.
  • the additive may include a material useful as electrical conductivity modifying agent.
  • the additive may include a material such as graphite, carbon black, or nickel and may have an electrical resistivity of at most 10 W.ah.
  • the additive may be a high permittivity agent, configured to absorb radiation in the lOOMHz to 10 GHz range.
  • Some suitable examples of such additives include Ti0 2 , BaTi0 3 , or CaZr0 3 and may have a dielectric constant of at least 20 at 1 GHz.
  • the additive may be a particulate material having an average particle size less than the average length of the boron nitride particles of the first phase.
  • the additive may be a particle having an average particle size less than an average width of the boron nitride particles of the first phase.
  • the additive can be a particle having an average particle size less than an average thickness of the boron nitride particles on the first phase.
  • the particulate material of the embodiments herein may be added to certain objects and materials to form thermally conductive members, including but not limited to articles such as thermal interface materials (e.g., thermal pastes or thermal dissipaters), laminates, pre-pregs for electronic devices (e.g., printed circuit boards), and the like.
  • thermal interface materials e.g., thermal pastes or thermal dissipaters
  • laminates e.g., laminates
  • pre-pregs for electronic devices e.g., printed circuit boards
  • FIG. 3 includes a cross-sectional illustration of a thermal management article according to an embodiment.
  • the thermal management article 300 includes a body 301 including particulate material 302 and a binder material 303 contained within the body.
  • the thermal management article 300 may be positioned within electronic devices to draw heat away from sensitive electronic components. For example, at least one of the exterior surfaces 311 or 312 of the body 301 may be in contact with electronic devices that create heat.
  • the 301 is used to draw heat away from the sensitive electronic components positioned on one of the exterior surface 311 or 312 and through the body 301.
  • binder material 303 in the body 301 can vary depending upon the intended application.
  • the binder material can include an organic material, inorganic material or any combination thereof.
  • the binder material may include an organic material such as a thermoplastic, thermoset, or any combination thereof. More specifically, the binder material may include a material select from the group of polyurethane, epoxy, formaldehyde, phenolic, silicone, fluoropolymer, polysulfone, sulfite, polycarbonate, polyacrylic, polyamide, polyimide, polyester, or any combination thereof.
  • Embodiment 1 A particulate material comprising:
  • a second phase comprising an organic material contained within pores of the body.
  • Embodiment 2 A particulate material comprising:
  • a body including:
  • a first phase including boron nitride particles, having an average contact length of at least 0.08 microns;
  • a second phase comprising an organic material contained within pores of the body.
  • Embodiment 3 A particulate material comprising:
  • a body including:
  • a first phase including boron nitride particles, wherein at least 25% of the boron nitride particles are in direct contact with each other;
  • Embodiment 4 The particulate material of any one of embodiments 1, 2 and 3, wherein the first phase comprises hexagonal boron nitride.
  • Embodiment 5 The particulate material of any one of embodiments 1, 2 and 3, wherein the first phase comprises a majority content of boron nitride.
  • Embodiment 6 The particulate material of any one of embodiments 1, 2, and 3, wherein the first phase comprises at least 60 vol% boron nitride for a total volume of the first phase or at least 70 vol% or at least 80 vol% or at least 90 vol% or at least 95 vol% or at least 99 vol% boron nitride for a total volume of the body.
  • Embodiment 7 The particulate material of any one of embodiments 1, 2 and 3, wherein the first phase consists essentially of hexagonal boron nitride.
  • Embodiment 8 The particulate material of any one of embodiments 1, 2 and 3, wherein the body comprises not greater than 1 wt% of boron oxide (B203) for a total weight of the body or not greater than 0.9 wt% or not greater than 0.8 wt% or not greater than 0.7 wt% or not greater than 0.6 wt% or not greater than 0.5 wt%.
  • B203 boron oxide
  • Embodiment 9 The particulate material of any one of embodiments 1, 2 and 3, wherein the body comprises not greater than 1 wt% of Ca for a total weight of the body, or not greater than 0.1 wt%, or not greater than 0.05 wt%, or not greater than 0.01 wt%, or not greater than 0.001 wt%.
  • Embodiment 10 The particulate material of any one of embodiments 1, 2 and 3, wherein the body comprises not greater than 1 wt% of an alkali-containing species for a total weight of the body or not greater than 0.1 wt% or not greater than 0.01 wt% or not greater than 0.001 wt% of an alkali-containing species for a total weight of the body.
  • Embodiment 11 The particulate material of any one of embodiments 1, 2 and 3, wherein the body comprises at least 10 vol% and not greater than 80 vol% content of the first phase for a total volume of the body or within a range of at least 20 vol% and not greater than 70 vol% or within a range including at least 30 vol% and not greater than 60 vol% or within a range of at least 35 vol% and not greater than 55 vol% or within a range including at least 35 vol% and not greater than 50 vol%.
  • Embodiment 12 The particulate material of any one of embodiments 1, 2 and 3, wherein the body comprises at least 10 vol% of the first phase for a total volume of the body or at least 12 vol% or at least 15 vol% or at least 20 vol% or at least 25 vol% or at least 30 vol% or at least 35 vol% or at least 40 vol% or at least 45 vol% or at least 50 vol% or at least 55 vol% or at least 60 vol% or at least 65 vol% or at least 70 vol% or at least 75 vol% for a total volume of the body.
  • Embodiment 13 The particulate material of any one of embodiments 1, 2 and 3, wherein the body comprises not greater than 80 vol% of the first phase for a total volume of the body or not greater than 75 vol% or not greater than 70 vol% or not greater than 65 vol% or not greater than 60 vol% or not greater than 55 vol% or not greater than 50 vol% or not greater than 45 vol% or not greater than 40 vol% or not greater than 35 vol% or not greater than 30 vol% or not greater than 25 vol% or not greater than 20 vol% or not greater than 15 vol%.
  • Embodiment 14 The particulate material of any one of embodiments 1, 2 and 3, wherein the first phase comprises a network of polycrystalline particles, wherein the
  • polycrystalline particles have an average length of at least 0.2 micron and not greater than 50 microns or within a range including at least 1 micron to not greater than 40 microns or within a range including at least 2 microns and not greater than 30 microns or within a range including at least 3 microns and not greater than 20 microns or within a range including at least 5 microns and not greater than 10 microns.
  • Embodiment 15 The particulate material of any one of embodiments 1, 2 and 3, wherein the boron nitride particles comprise an average length of at least 0.2 micron and not greater than 50 microns or within a range including at least 1 micron to not greater than 40 microns or within a range including at least 2 microns and not greater than 30 microns or within a range including at least 3 microns and not greater than 20 microns or within a range including at least 5 microns and not greater than 10 microns.
  • Embodiment 16 The particulate material of any one of embodiments 1, 2 and 3, wherein the boron nitride particles comprise an average thickness within a range of at least 0.1 microns and not greater than 5 microns or within a range including at least 0.5 microns to not greater than 4 microns or within a range including at least 0.8 microns and not greater than 4 microns or within a range including at least 1 micron and not greater than 4 microns or within a range including at least 1 microns and not greater than 3 microns.
  • Embodiment 17 The particulate material of any one of embodiments 1, 2 and 3, wherein the boron nitride particles are platelet- shaped particles having a length, a width, and a thickness, wherein the length>width>thickness.
  • Embodiment 18 The particulate material of embodiment 17, wherein the boron nitride particles comprise a primary aspect ratio of lengthdhickness of at least 1: 1 or at least 1.2: 1 or at least 1.5: 1 or at least 2: 1 or at least 2.5: 1 or at least 3: 1 or at least 4: 1 or at least 5: 1 or at least 10: 1.
  • Embodiment 19 The particulate material of embodiment 17, wherein the boron nitride particles comprise a primary aspect ratio of lengthdhickness of not greater than 50: 1 or not greater than 30: 1 or not greater than 20: 1 or not greater than 10: 1 or not greater than 5: 1 or not greater than 2: 1 or not greater than 1: 1.
  • Embodiment 20 The particulate material of any one of embodiments 1, 2 and 3, wherein at least a portion of the boron nitride particles are sinter-bonded to each other.
  • Embodiment 21 The particulate material of embodiment 20, wherein at least 25% of the boron nitride particles are sinter-bonded to each other, or at least 30% or at least 40% or at least 50% or at least 60% or at least 70% or at least 80% or at least 90%.
  • Embodiment 22 The particulate material of embodiment 20, wherein not greater than 99% of the boron nitride particles are sinter-bonded to each other.
  • Embodiment 23 The particulate material of any one of embodiments 1, 2 and 3, wherein at least a portion of the boron nitride particles define a sintered polycrystalline network.
  • Embodiment 24 The particulate material of any one of embodiments 2 and 3, wherein the body comprises a Normalized Thermal Conductivity of at least 0.01 Wcm /g-K.
  • Embodiment 25 The particulate material of any one of embodiments 1 and 24, wherein the body comprises a Normalized Thermal Conductivity of at least 0.011 Wcm /g-K or at least 0.012 Wcm 2 /g- K or at least 0.013 Wcm 2 /g- K or at least 0.014 Wcm 2 /g- K or at least 0.015 Wcm 2 /g-K or at least 0.016 Wcm 2 /g-K or at least 0.02 Wcm 2 /g-K or at least 0.022 Wcm 2 /g- K or at least 0.025 Wcm 2 /g- K or at least 0.028 Wcm 2 /g- K.
  • a Normalized Thermal Conductivity of at least 0.011 Wcm /g-K or at least 0.012 Wcm 2 /g- K or at least 0.013 Wcm 2 /g- K or at least 0.014 Wcm 2 /g- K or at least 0.015
  • Embodiment 26 The particulate material of any one of embodiments 1 and 24, wherein the body comprises a Normalized Thermal Conductivity of not greater than 0.3
  • Wcm /g- K or not greater than 0.2 Wcm /g- K or not greater than 0.1 Wcm /g- K or not greater than 0.05 Wcm 2 /g- K.
  • Embodiment 27 The particulate material of any one of embodiments 1, 2 and 3, wherein the first phase has an average contact length of at least 0.08 microns.
  • Embodiment 28 The particulate material of any one of embodiments 2 and 27, wherein the average contact length is at least 0.09 microns or at least 0.1 microns or at least 0.11 microns or at least 0.12 microns or at least 0.13 microns or at least 0.14 microns or at least 0.15 microns or at least 0.16 microns or at least 0.17 microns or at least 0.18 microns or at least 0.19 microns or at least 0.2 microns.
  • Embodiment 29 The particulate material of any one of embodiments 2 and 27, wherein the average contact length is not greater than 5 microns or not greater than 4 microns or not greater than 3 microns or not greater than 2 microns.
  • Embodiment 30 The particulate material of embodiment 1, wherein at least 5% of the exterior surface of the body comprises the first phase.
  • Embodiment 31 The particulate material of any one of embodiments 2 and 3, and 30, wherein at least 8% of the exterior surface of the body comprises the first phase or at least 10% or at least 12% or at least 15% or at least 18% or at least 20% or at least 22% or at least
  • Embodiment 32 The particulate material of any one of embodiments 2 and 3, and 30, wherein not greater than 99% of the exterior surface of the body comprises the first phase or not greater than 95% or not greater than 93% or not greater than 90% or not greater than 87% or not greater than 85% or not greater than 83% or not greater than 80% or not greater than 77% or not greater than 75% or not greater than 73% or not greater than 70% or not greater than 67% or not greater than 65% or not greater than 63% or not greater than 60% or not greater than 57% or not greater than 55% or not greater than 53% or not greater than 50% or not greater than 47% or not greater than 45% or not greater than 43% or not greater than 40% or not greater than 37% or not greater than 35% or not greater than 33% or not greater than 30% or not greater than 27% or not greater than 25% or not greater than 23% or not greater than 20% or not greater than 17% or not greater than 15% or not greater than 13% or not greater than 10% or not greater than 7%.
  • Embodiment 33 The particulate material of any one of embodiments 2 and 3, and 30, wherein at least 5% and not greater than 99% of the exterior surface of the body comprises the first phase or at least 10% and not greater than 90% of the exterior surface of the body comprises the first phase or at least 20% and not greater than 80% of the exterior surface of the body comprises the first phase or at least 30% and not greater than 60% of the exterior surface of the body comprises the first phase or at least 30% and not greater than 50% of the exterior surface of the body comprises the first phase.
  • Embodiment 34 The particulate material of any one of embodiments 1 and 2, wherein at least 25% of the boron nitride particles are in direct contact with each other.
  • Embodiment 35 The particulate material of any one of embodiments 3 and 34, wherein at least 27% of the boron nitride particles are in direct contact with each other or at least 30% or at least 33% or at least 35% or at least 37% or at least 40% or at least 43% or at least
  • Embodiment 36 The particulate material of any one of embodiments 3 and 34, wherein not greater than 99% of the boron nitride particles are in direct contact with each other or not greater than 95% or not greater than 92% or not greater than 90% or not greater than 87% or not greater than 85% or not greater than 82% or not greater than 80% or not greater than 77% or not greater than 75% or not greater than 72% or not greater than 70% or not greater than 67% or not greater than 65% or not greater than 62% or not greater than 60% or not greater than 57% or not greater than 55% or not greater than 52% or not greater than 50% or not greater than 47% or not greater than 45% or not greater than 42% or not greater than 40% or not greater than 37% or not greater than 35% or not greater than 32% or not greater than 30% or not greater than 27%.
  • Embodiment 37 The particulate material of any one of embodiments 1, 2 and 3, wherein the organic material of the second phase comprises a material selected from the group consisting of a thermoset, a thermoplastic, or any combination thereof.
  • Embodiment 38 The particulate material of any one of embodiments 1, 2 and 3, wherein the organic material of the second phase comprises a material selected from the group consisting of acrylics, vinyls, esters, polyesters, urethanes, phenolics, furans, ureas,
  • thermoset for an entire volume of the second phase or at least 60 vol% or at least 70 vol% or at least 80 vol% or at least 90 vol% or at least 95 vol% of a thermoset for an entire volume of the second phase.
  • Embodiment 40 The particulate material of any one of embodiments 1, 2 and 3, wherein the second phase consists essentially of an organic material.
  • Embodiment 41 The particulate material of any one of embodiments 1, 2 and 3, wherein the second phase consists essentially of one of a silicone resin, epoxy resin, phenolformaldehyde, bismaleimide, cyanate ester, phenolic resin, or any combination thereof.
  • Embodiment 42 The particulate material of any one of embodiments 1, 2 and 3, wherein the body comprises at least 10 vol% of the second phase for a total volume of the body or at least 12 vol% or at least 15 vol% or at least 20 vol% or at least 25 vol% or at least 30 vol% or at least 35 vol% or at least 40 vol% or at least 45 vol% or at least 50 vol% or at least 55 vol% or at least 60 vol% or at least 65 vol% or at least 70 vol% or at least 75 vol% for a total volume of the body.
  • Embodiment 43 The particulate material of any one of embodiments 1, 2 and 3, wherein the body comprises not greater than 80 vol% of the second phase for a total volume of the body or not greater than 75 vol% or not greater than 70 vol% or not greater than 65 vol% or not greater than 60 vol% or not greater than 55 vol% or not greater than 50 vol% or not greater than 45 vol% or not greater than 40 vol% or not greater than 35 vol% or not greater than 30 vol% or not greater than 25 vol% or not greater than 20 vol% or not greater than 15 vol%.
  • Embodiment 44 The particulate material of any one of embodiments 1, 2 and 3, wherein the body consists essentially of the first phase and the second phase.
  • Embodiment 45 The particulate material of any one of embodiments 1, 2 and 3, wherein the second phase comprises a Rockwell R hardness of at least 100 or at least 110 or at least 120 or at least 130 or at least 140 or at least 150.
  • Embodiment 46 The particulate material of any one of embodiments 1, 2 and 3, wherein the second phase comprises an Izod Impact strength of at least 0.1 ft- lb/in or at least 0.2 ft-lb/in or at least 0.3 ft-lb/in or at least 0.4 ft-lb/in or at least 0.5 ft-lb/in.
  • Embodiment 47 The particulate material of any one of embodiments 1, 2 and 3, wherein the second phase comprises a water absorption of not greater than 0.5% according to ASTM D570 standard.
  • Embodiment 48 The particulate material of any one of embodiments 1, 2 and 3, wherein the second phase comprises a flammability of V-0 according UL94 standard.
  • Embodiment 49 The particulate material of any one of embodiments 1, 2 and 3, further comprising at least one additive contained within the second phase.
  • Embodiment 50 The particulate material of embodiment 49, wherein the additive includes an inorganic material.
  • Embodiment 51 The particulate material of embodiment 49, wherein the additive includes at least one composition selected from the group consisting of oxides, carbides, nitrides, borides, or any combination thereof.
  • Embodiment 52 The particulate material of embodiment 49, wherein the additive includes a ceramic, a glass, a metal or metal alloy.
  • Embodiment 53 The particulate material of embodiment 49, wherein the additive comprises a composition including at least one element from the group consisting of an alkali element, alkali earth element, a transition metal element, a lanthanide, a chalcogenide, a halogen, or any combination thereof.
  • Embodiment 54 The particulate material of embodiment 49, wherein the additive includes a pigment.
  • Embodiment 55 The particulate material of embodiment 49, wherein the additive includes an electrical conductivity modifying agent.
  • Embodiment 56 The particulate material of embodiment 49, wherein the additive includes a luminescent agent.
  • Embodiment 57 The particulate material of embodiment 49, wherein the additive is a particulate comprising an average particle size less than the average length of the boron nitride particles of the first phase.
  • Embodiment 58 The particulate material of embodiment 49, wherein the additive is a particulate comprising an average particle size less than the average width of the boron nitride particles of the first phase.
  • Embodiment 59 The particulate material of embodiment 49, wherein the additive is a particulate comprising an average particle size less than the average thickness of the boron nitride particles of the first phase.
  • Embodiment 60 The particulate material of any one of embodiments 1, 2 and 3, wherein the particulate is contained within a binder material.
  • Embodiment 61 The particulate material of embodiment 60, wherein the binder material comprises an organic material, an inorganic material or any combination thereof.
  • Embodiment 62 The particulate material of embodiment 60, wherein the binder material comprises an organic material selected from the group consisting of thermoplastics, thermosets or any combination thereof.
  • Embodiment 63 The particulate material of embodiment 60, wherein the binder material comprises a material selected from the group consisting of urethane, resin, epoxy, formaldehyde, phenolic, silicone, fluoropolymer, sulfone, sulfite, carbonate, acrylic, polyamide, polyimide, ester, or any combination thereof.
  • the binder material comprises a material selected from the group consisting of urethane, resin, epoxy, formaldehyde, phenolic, silicone, fluoropolymer, sulfone, sulfite, carbonate, acrylic, polyamide, polyimide, ester, or any combination thereof.
  • Embodiment 64 A thermal management article including the particulate material of any one of embodiments 1, 2, and 3 and a binder.
  • Embodiment 65 An electronic device coupled to a substrate, wherein the substrate comprises the particulate material of any one of embodiments 1, 2 and 3.
  • Embodiment 66 A laminate material comprising the particulate material of any one of embodiments 1, 2, and 3.
  • Embodiment 67 A paste material comprising the particulate material of any one of embodiments 1, 2, and 3.
  • Embodiment 68 A method for forming a particulate material comprising: heating a first phase comprising boron nitride to form an intermediate body having at least a portion of the boron nitride particles bonded to each other within the intermediate body; and infiltrating a porosity of the intermediate body with a second phase to form a body having a Normalized Thermal Conductivity of at least 0.01 Wcm /g-K.
  • Embodiment 69 The method of embodiment 68, wherein heating comprises sintering at least a portin of the boron nitride particles to each other.
  • Embodiment 70 The method of embodiment 68, wherein heating comprises forming a sinter-bond between at least a portion of the boron nitride particles.
  • Embodiment 71 The method of embodiment 68, wherein heating is conducted at a sintering temperature within a range of at least l500°C to not greater than 2500°C.
  • Embodiment 72 The method of embodiment 68, further comprising shaping the first phase using a process selected from the group consisting of pressing, molding, cutting, extruding, drying, or any combination thereof.
  • Embodiment 73 The method of embodiment 72, wherein shaping is conducted prior to heating.
  • Embodiment 74 The method of embodiment 68, wherein the intermediate body includes a plurality of discrete particles comprising boron nitride, each of the discrete particles having the porosity to be infiltrated by the second phase.
  • Embodiment 75 The method of embodiment 68, wherein the intermediate body is a single monolithic body comprising boron nitride and the porosity within the intermediate body to be infiltrated by the second phase.
  • Embodiment 76 The method of embodiment 68, wherein the porosity of the intermediate body is at least 10 vol% for the total volume of the intermediate body or at least 20 vol% or at least 30 vol% or at least 40 vol% or at least 50 vol% or at least 60 vol% or at least 70 vol% or at least 80 vol%.
  • Embodiment 77 The method of embodiment 68, wherein the porosity of the intermediate body is not greater than 90 vol% for a total volume of the intermediate body or not greater than 80 vol% or not greater than 70 vol% or not greater than 60 vol% or not greater than 50 vol% or not greater than 40 vol% or not greater than 30 vol% or not greater than 20 vol%.
  • Embodiment 78 The method of embodiment 68, wherein infiltrating includes mixing the intermediate body with the second phase to infiltrate the porosity of the intermediate body with the second phase.
  • Embodiment 79 The method of embodiment 68, wherein infiltrating comprises immersing the intermediate body in the second phase to infiltrate the porosity of the intermediate body with the second phase
  • Embodiment 80 The method of embodiment 68, wherein infiltrating further comprises applying a pressure differential to the intermediate body and applying a force on the second phase to infiltrate the porosity of the intermediate body with the second phase.
  • Embodiment 81 The method of embodiment 68, further comprising heating the particulate after infiltration.
  • Embodiment 82 The method of embodiment 81, wherein heating includes heating to a curing temperature to cure at least a portion of the second phase.
  • Embodiment 83 The method of embodiment 82, wherein the curing temperature is within a range of at least 30°C to not greater than 200°C.
  • Embodiment 84 The method of embodiment 82, wherein heating comprises holding the body at the curing temperature for a curing duration within a range of at least 1 minute to not greater than 2 hours.
  • Embodiment 85 The method of embodiment 68, further comprising crushing the body after infiltration to form a particulate material.
  • Embodiment 86 The method of embodiment 85, further comprising sieving the particulate material after crushing.
  • Embodiment 87 The method of embodiment 85, wherein a maximum particle size of the particulate material is not greater than 500 microns, such as not greater than 400 microns, not greater than 300 microns, or not greater than 200 microns.
  • Embodiment 88 The method of embodiment 68, wherein the body includes any feature of any of the preceding embodiments.
  • a comparative example (Sample CS1) was formed by creating a mixture of 40 wt% particulate material with 60 wt% polyamide 6.
  • the particulate material was PCTP-8 BN powder commercialized by Saint-Gobain.
  • the polyamide 6 was H35ZI PA 6 commercialized by AdvanSix Aegis.
  • the particulate material and polyamide 6 were mixed in a twin screw extruder from Leistriz, ZSE-18 HP-e 40D with an 18 mm diameter barrel, using co-rotating conditions with a screw speed of 300 rpm. The extruded pellets were crushed under dry conditions then sieved to to a range of 50 microns and to 150 microns.
  • FIG. 4A includes a cross-sectional scanning electron microscope image of the particulate material of Sample CS 1.
  • the image of FIG. 4A includes a portion of a body 401 including a first phase 402 including particles of boron nitride and a second phase 403 of the polyamide 6.
  • Sample CS1 has a Normalized Thermal Conductivity of 0.007 Wcm /g-K, a percentage of boron nitride particles in contact with each other of 20% and an average contact length of 0.05 microns.
  • FIG. 4B includes a black and white image used to evaluate the percentage of boron nitride particles in contact with each other and the average contact length.
  • sample S2 A representative sample (Sample S2) was formed by mixing 114.5 g of NuSil GEL- 8100 Parts A & B in a 1: 1 ratio to form a second phase material. Approximately 200 grams of sintered boron nitride particulate raw material was mixed with the second phase material.
  • the sintered boron nitride particulate raw material was available as CTS7M from Saint-Gobain Corporation and consists essentially of h-BN with less than 0.25 wt% oxygen, less than 0.2 wt% boron oxide, less than 500 ppm of silicon and less than 500 ppm of calcium.
  • the sintered boron nitride particulate raw material had an average particle size of approximately 120 microns, a maximum particle size of approximately 180 microns, a bulk porosity of approximately 0.8 g/cc, an average pore size of approximately 1 micron, an average platelet length of 6-7 microns.
  • Sample S2 had a Normalized Thermal Conductivity of 0.015 W/mK, a percentage of boron nitride particles in contact with each other of 95% and an average contact length of 0.2 microns.
  • sample S3 A representative sample (Sample S3) was formed by cold isostatic pressing boron nitride powder into a green body having a 50 mm diameter and a density of approximately 1.4 g/cc.
  • the boron nitride particulate raw material consisted essentially of h-BN with less than 10 wt% oxygen, a bulk density of approximately 2 g/cm3, a specific surface area of 26 m2/g, and an average particle size (D50) of approximately 5 microns.
  • the green body was sintered to a sintered body in a non-oxidizing (i.e., nitrogen) atmosphere at 2050°C for 5 hours.
  • the sintered body was crushed and sieved into a boron nitride particulate raw material (herein also called sintered intermediate body) having a D50 particle size of about 5 microns, wherein each particle of the raw material contained a plurality of fused boron nitride particles forming an interconnected network.
  • the sintered, intermediate body consisted essentially of h-BN with less than 0.25 wt% oxygen, less than 0.2 wt% boron oxide, and less than 500 ppm of calcium.
  • the sintered, intermediate body had a bulk porosity of approximately 0.6 g/cc, and each particle of the sintered intermediate body had an average pore size of approximately 1 micron, an average platelet length of 6-7 microns.
  • the sintered, intermediate body was infiltrated by immersing the particles of the intermediate body in a second phase material of epoxy commercially available as EpoKwick FC from Buehler. During immersion, a reduced pressure atmosphere was provided of approximately 10 Pa for a duration of 10 minutes. The resulting infiltrated body was removed from the epoxy and the excess epoxy was removed from the exterior surface. The infiltrated body was cured at room temperature for at least 2 hours. The monolithic and infiltrated body was crushed in a roll crusher and sieved between 75 microns and 180 microns.
  • the resulting particulate material contained approximately 55 vol% epoxy, an average particle size of approximately 110 microns, a maximum particle size of approximately 180 microns, a surface area of approximately 0.4m /g, and a bulk porosity of less than 0.1 cc/g.
  • FIG. 5 includes a cross-sectional scanning electron microscope image of one representatice particle agglomerate of the particulate material of Sample S3. The image of FIG.
  • Sample S3 shows a magnified portion of the particle agglomerate having a first phase 502 including particles of boron nitride and a second phase 503 of the epoxy.
  • Sample S3 had a Normalized Thermal Conductivity of 0.015 Wcm / g-K, a percentage of boron nitride particles in contact with each other of approximately 95% and an average contact length of 0.2 microns.

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Abstract

La présente invention concerne un matériau particulaire comprenant un corps ayant une conductivité thermique normalisée d'au moins 0,01 Wcm2/g•K, le corps comprenant en outre une première phase comprenant des particules de nitrure de bore, au moins une partie des particules de nitrure de bore étant liées l'une à l'autre, et une seconde phase comprenant un matériau organique contenu dans les pores du corps.
PCT/US2019/024759 2018-03-30 2019-03-29 Matériau particulaire et son procédé de formation WO2019191541A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105453707A (zh) * 2013-08-14 2016-03-30 电化株式会社 氮化硼-树脂复合体电路基板、氮化硼-树脂复合体散热板一体型电路基板
US20160130187A1 (en) * 2013-06-03 2016-05-12 Denka Company Limited Resin-impregnated boron nitride sintered body and use for same
US20160145411A1 (en) * 2013-06-19 2016-05-26 3M Innovative Properties Company Component part produced from a polymer/boron nitride compound; polymer/boron nitride compound for producing such a component part and use thereof
US20170362440A1 (en) * 2016-05-27 2017-12-21 Saint-Gobain Ceramics & Plastics, Inc. Process for manufacturing boron nitride agglomerates
CN107735437A (zh) * 2015-06-17 2018-02-23 欧洲技术研究圣戈班中心 基于氮化硼的聚集体的粉末

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160130187A1 (en) * 2013-06-03 2016-05-12 Denka Company Limited Resin-impregnated boron nitride sintered body and use for same
US20160145411A1 (en) * 2013-06-19 2016-05-26 3M Innovative Properties Company Component part produced from a polymer/boron nitride compound; polymer/boron nitride compound for producing such a component part and use thereof
CN105453707A (zh) * 2013-08-14 2016-03-30 电化株式会社 氮化硼-树脂复合体电路基板、氮化硼-树脂复合体散热板一体型电路基板
CN107735437A (zh) * 2015-06-17 2018-02-23 欧洲技术研究圣戈班中心 基于氮化硼的聚集体的粉末
US20170362440A1 (en) * 2016-05-27 2017-12-21 Saint-Gobain Ceramics & Plastics, Inc. Process for manufacturing boron nitride agglomerates

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