US20230217971A1 - Nano-structured Aluminum Nitride (AlN) in a pure form and in the wurtzite phase of AlN from nut shells - Google Patents
Nano-structured Aluminum Nitride (AlN) in a pure form and in the wurtzite phase of AlN from nut shells Download PDFInfo
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- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 title claims abstract description 58
- PIGFYZPCRLYGLF-UHFFFAOYSA-N Aluminum nitride Chemical compound [Al]#N PIGFYZPCRLYGLF-UHFFFAOYSA-N 0.000 title claims abstract description 8
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- 239000000843 powder Substances 0.000 claims abstract description 45
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 19
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- 238000010438 heat treatment Methods 0.000 claims abstract description 7
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- 238000003825 pressing Methods 0.000 claims abstract 4
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- 238000001069 Raman spectroscopy Methods 0.000 claims description 5
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- 230000005855 radiation Effects 0.000 claims description 3
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- 244000144725 Amygdalus communis Species 0.000 description 17
- 235000020224 almond Nutrition 0.000 description 17
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- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 13
- 240000006711 Pistacia vera Species 0.000 description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 10
- 235000020234 walnut Nutrition 0.000 description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 244000060011 Cocos nucifera Species 0.000 description 8
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- 230000015572 biosynthetic process Effects 0.000 description 7
- 244000226021 Anacardium occidentale Species 0.000 description 6
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- 239000000203 mixture Substances 0.000 description 6
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
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- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000001157 Fourier transform infrared spectrum Methods 0.000 description 2
- 240000007594 Oryza sativa Species 0.000 description 2
- 235000007164 Oryza sativa Nutrition 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 241000209140 Triticum Species 0.000 description 2
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- 229910021529 ammonia Inorganic materials 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
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- 235000012431 wafers Nutrition 0.000 description 2
- XSMMCTCMFDWXIX-UHFFFAOYSA-N zinc silicate Chemical compound [Zn+2].[O-][Si]([O-])=O XSMMCTCMFDWXIX-UHFFFAOYSA-N 0.000 description 2
- 235000019352 zinc silicate Nutrition 0.000 description 2
- 235000017060 Arachis glabrata Nutrition 0.000 description 1
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 238000003991 Rietveld refinement Methods 0.000 description 1
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Images
Classifications
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- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
- A23L25/00—Food consisting mainly of nutmeat or seeds; Preparation or treatment thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
- B02C17/18—Details
- B02C17/20—Disintegrating members
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B21/00—Nitrogen; Compounds thereof
- C01B21/06—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
- C01B21/072—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with aluminium
- C01B21/0726—Preparation by carboreductive nitridation
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/80—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70
- C01P2002/82—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70 by IR- or Raman-data
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/04—Particle morphology depicted by an image obtained by TEM, STEM, STM or AFM
Definitions
- This invention concerns a new method for the formation of abundant quantities of Aluminum Nitride (AlN) from a thermal treatment of a mixture of aluminum oxide (Al 2 O 3 ) and shells of almond, cashew, coconuts, pistachio, and walnuts in a nitrogen atmosphere at temperatures in excess of 1450° C.
- AlN Aluminum Nitride
- This new method of synthesizing Aluminum Nitride from various Nut Shells uses conventional heating or microwave heating to produce nano-structures.
- Billions of pounds of agricultural waste of nut shells such as those of almonds, pistachios, walnuts, cashew, coconuts, macadamia etc. are generated every year all over the world.
- Aluminum Nitride (AlN) is a very useful material for industrial and electronic applications due to its unique physical properties.
- AlN is an insulator in electronic device applications because of high electrical resistivity, low thermal expansion, resistance to erosion and corrosion, excellent thermal shock resistance and chemical stability in air up to 1380° C. with surface oxidation occurring at 780° C.
- SAWs Surface acoustic wave sensors
- silicon wafers because of AlN's piezoelectric properties and AlN can be used as an RF filter for mobile phones.
- AlN is synthesized in the bulk form by the carbothermal reduction of aluminum oxide in the presence of gaseous nitrogen or ammonia or by direct nitridation of aluminum.
- Y 2 O 3 or CaO are required as additives during the hot pressing.
- Aluminum nitride is a wide gap semiconductor with band gap between 6.01-6.05 eV at room temperature. It crystallizes in wurtzite phase and has many potential applications in microelectronics due to its relatively high thermal conductivity (70-210 NV-m ⁇ 1 ⁇ K ⁇ 1 to 285 W ⁇ m ⁇ 1 K ⁇ 1 ).
- other unique properties that make it an attractive for applications include high electrical resistivity, low thermal expansion, resistance to erosion and corrosion, excellent thermal shock resistance and chemical stability in air up to 1380° C. with surface oxidation occurring at 780° C.
- Epitaxially grown thin film crystalline aluminum nitride is used for surface acoustic wave sensors (SAWs) deposited on silicon wafers because of AlN's piezoelectric properties.
- SAWs surface acoustic wave sensors
- Another important application for AlN is its application as an RF filter which is widely used in mobile phones, which is also called a thin film bulk acoustic resonator (FBAR).
- FBAR thin film bulk acoustic resonator
- AlN is synthesized in the bulk form by the carbothermal reduction of aluminum oxide in the presence of gaseous nitrogen or ammonia or by direct nitridation of aluminum.
- Y 2 O 3 or CaO are required as additives during the hot pressing.
- the agriculture waste products there are two types, one containing silica and carbonaceous matter and the other one contains mostly carbonaceous matter and no silica.
- the first kind includes rice husk, wheat husk, and peanut shells. We have demonstrated that they can be utilized to produce industrially important materials such as SiO 2 , SiC, Si 3 N 4 , and zinc silicate by pyrolizing them in air, argon or in nitrogen atmospheres.
- the second kind of agriculture residues are nut shells which contain only carbonaceous matter such as almond, walnuts, pistachio, coconuts, macadamia, cashew, etc. Billions of pounds of nut shells are produced annually all over the world and will be available if they can be harnessed in the synthesis of industrially important materials. Recently, it was reported that mixed phases of SiC and Si 3 N 4 can be produced by carbothermal reduction and nitridation of a mixture of silica and macadamia powder.
- a new method of making Aluminum Nitride from Nut Shells involving the formation of abundant quantities of MN from a thermal treatment of a mixture of aluminum oxide (Al 2 O 3 ) and shells of almond, cashew, coconuts, pistachio, and walnuts in a nitrogen atmosphere at temperatures in excess of 1450° C.
- FIG. 1 illustrates X-ray diffraction patterns taken with CuK ⁇ radiation of AlN synthesized from Almond powder and aluminum oxide powder in nitrogen at a temperature of 1450° C. showing the wurtzite phase.
- FIG. 2 A illustrates a TEM micrograph of AlN samples fabricated from almond showing the nanocrystalline nature.
- FIG. 2 B illustrates a TEM micrograph of AlN samples fabricated from almond showing the nanocrystalline nature.
- FIG. 2 C illustrates a TEM micrograph of AlN samples fabricated from walnut showing the nanocrystalline nature.
- FIG. 2 D illustrates a TEM micrograph of AlN samples fabricated from walnut showing the nanocrystalline nature.
- FIG. 3 illustrates Raman Spectra of the AlN sample derived from almond confirming the wurtzite phase.
- FIG. 4 A illustrates X-ray diffraction scan of Al 2 O 3 mixed with almond showing peaks corresponding to corundum phase.
- the vertical lines correspond to the expected peaks of alumina.
- FIG. 4 B illustrates a Rietveld whole profile analysis of the diffraction pattern for the AlN sample derived from almond after pyrolising in a nitrogen atmosphere followed by treatment in air at 800° C.
- FIG. 5 A illustrates Raman spectra of AlN derived from pistachio showing the different Raman active modes.
- FIG. 5 B illustrates Raman spectra of AlN derived from almond showing the different Raman active modes.
- FIG. 5 C illustrates FTIR spectra of AlN derived from pistachio showing a broad band of 699 cm ⁇ 1 .
- FIG. 5 D illustrates FTIR spectra of AlN derived from almond showing a broad band of 698 cm ⁇ 1 .
- FIG. 6 illustrates EDX of AlN derived from almond nut shell after pyrolysing in N 2 and followed by heat treatment in O 2 to remove excessive carbon.
- the inventors have discovered a method of forming pure AlN by carbothermal reduction of Al 2 O 3 with raw nuts of almonds, coconuts, macadamia, pistachios, and walnuts in the presence of a N 2 atmosphere to produce nano-tubes and nanoparticles previously not formed by other processing then purified in an O 2 atmosphere in a Al 2 O 3 crucible.
- the production process involves preparing samples from powders of raw nuts of almonds, coconuts, macadamia, pistachios, and walnuts after mixing them with nanocrystalline Al 2 O 3 powder using ball milling with a SPEX 8000M including stainless steel milling media.
- the Al 2 O 3 sample along with the specific nut shell was combined and milled to obtain a uniform powder.
- a hydraulic press was used to pressurize the homogenous powder into 1 cm diameter disks with a 2.5-3 mm depth.
- the pellets were heat treated (pyrolised) in a conventional furnace at temperatures exceeding 1400° C. for an interval of 5-6 hours in a nitrogen atmosphere.
- the pellets were then placed in air at 670° C.
- XRD scans were obtained using a Rigaku 18 kW rotating anode generator and a high resolution powder diffractometer. The diffraction scans were collected using monochromatic CuK ⁇ radiation.
- Raman spectra were collected on an inVia Raman Microscope (Renishaw) using a 514 nm laser line.
- Scans were obtained at ca. 15 mW laser power at the sample and an integration period of 30 seconds.
- ethyl alcohol was mixed with the pyrolyzed sample; the mixture was then set in an ultrasonic cleaner.
- a carbon covered 200 mesh copper grid was submerged into the mixture to collect AlN particles.
- a FEI Tecnai G2 TEM was utilized to examine the sample at 300 kV.
- Nuts have very little SiO 2 uptake from the ground but still is a carbon source. Therefore nuts are a great candidate to mix with oxides to form a carbide and/or a nitride with further processing. The result is a pure nitride (in this case AlN) that is made in a simple cost effective process.
- AlN made from nuts such as almonds, pistachios, walnuts, cashew, coconuts, macadamia etc. can be made fully dense without the use of other dopants like AlN made in other ways. This provides a more pure bulk form of AlN.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Food Science & Technology (AREA)
- Nanotechnology (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Physics & Mathematics (AREA)
- Composite Materials (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Nutrition Science (AREA)
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- Crystallography & Structural Chemistry (AREA)
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- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
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Abstract
Nano-structures of Aluminum Nitride and a method of producing nano-structures of Aluminum Nitride from nut shells comprising milling agricultural nuts into a fine nut powder, milling nanocrystalline Al2O3 into a powder, mixing, pressing the fine nut powder and the powder of nanocrystalline Al2O3, heating the pellet, maintaining the temperature of the pellet at about 1400° C., cooling the pellet, eliminating the residual carbon, and forming nano-structures of AlN. An Aluminum Nitride (AlN) product made from the steps of preparing powders of agricultural nuts using ball milling, preparing powders of nanocrystalline Al2O3, mixing the powders of agricultural nuts and the powders of nanocrystalline Al2O3 forming a homogenous sample powder of agricultural nuts and Al2O3, pressurizing, pyrolizing the disk, and reacting the disk and the nitrogen atmosphere and forming AlN.
Description
- This application is a non-provisional of, and claims priority to and the benefits of, U.S. Patent Application No. 62/422,793 filed on Nov. 16, 2016 and U.S. patent application Ser. No. 15/786,180 filed on Oct. 17, 2017 and U.S. patent application Ser. No. 16/406,969 filed on May 8, 2019, and U.S. patent application Ser. No. 17/081,216 filed on Oct. 27, 2020, the entirety of each is hereby incorporated by reference.
- This invention concerns a new method for the formation of abundant quantities of Aluminum Nitride (AlN) from a thermal treatment of a mixture of aluminum oxide (Al2O3) and shells of almond, cashew, coconuts, pistachio, and walnuts in a nitrogen atmosphere at temperatures in excess of 1450° C.
- This new method of synthesizing Aluminum Nitride from various Nut Shells uses conventional heating or microwave heating to produce nano-structures.
- Billions of pounds of agricultural waste of nut shells such as those of almonds, pistachios, walnuts, cashew, coconuts, macadamia etc. are generated every year all over the world.
- Aluminum Nitride (AlN) is a very useful material for industrial and electronic applications due to its unique physical properties.
- AlN is an insulator in electronic device applications because of high electrical resistivity, low thermal expansion, resistance to erosion and corrosion, excellent thermal shock resistance and chemical stability in air up to 1380° C. with surface oxidation occurring at 780° C.
- Surface acoustic wave sensors (SAWs) can be deposited on silicon wafers because of AlN's piezoelectric properties and AlN can be used as an RF filter for mobile phones.
- AlN is synthesized in the bulk form by the carbothermal reduction of aluminum oxide in the presence of gaseous nitrogen or ammonia or by direct nitridation of aluminum. In order to get a fully dense form, Y2O3 or CaO are required as additives during the hot pressing.
- Aluminum nitride is a wide gap semiconductor with band gap between 6.01-6.05 eV at room temperature. It crystallizes in wurtzite phase and has many potential applications in microelectronics due to its relatively high thermal conductivity (70-210 NV-m−1·K−1 to 285 W·m−1K−1). In addition, other unique properties that make it an attractive for applications include high electrical resistivity, low thermal expansion, resistance to erosion and corrosion, excellent thermal shock resistance and chemical stability in air up to 1380° C. with surface oxidation occurring at 780° C.
- Epitaxially grown thin film crystalline aluminum nitride is used for surface acoustic wave sensors (SAWs) deposited on silicon wafers because of AlN's piezoelectric properties. Another important application for AlN is its application as an RF filter which is widely used in mobile phones, which is also called a thin film bulk acoustic resonator (FBAR). AlN is synthesized in the bulk form by the carbothermal reduction of aluminum oxide in the presence of gaseous nitrogen or ammonia or by direct nitridation of aluminum. In order to get fully dense form, Y2O3 or CaO are required as additives during the hot pressing.
- Among the agriculture waste products, there are two types, one containing silica and carbonaceous matter and the other one contains mostly carbonaceous matter and no silica. The first kind includes rice husk, wheat husk, and peanut shells. We have demonstrated that they can be utilized to produce industrially important materials such as SiO2, SiC, Si3N4, and zinc silicate by pyrolizing them in air, argon or in nitrogen atmospheres.
- The second kind of agriculture residues are nut shells which contain only carbonaceous matter such as almond, walnuts, pistachio, coconuts, macadamia, cashew, etc. Billions of pounds of nut shells are produced annually all over the world and will be available if they can be harnessed in the synthesis of industrially important materials. Recently, it was reported that mixed phases of SiC and Si3N4 can be produced by carbothermal reduction and nitridation of a mixture of silica and macadamia powder.
- We have demonstrated in our recent work that by adding ZnO to powder of wheat or rice husk, pure zinc silicate can be produced with photo-luminescent properties.
- Here, we have developed the formation of AlN from the nut shells powder by adding nanocrytalline powders of Al2O3 to the nut shells powder of almond, walnut, coconut, macadamia, pistachio and cashew and pyrolising them in nitrogen atmosphere at 1400 to 1500° C.
- Energy dispersive X-ray fluorescence technique was used to determine the elemental composition of the nuts with very slight variation among them. The formation of pure wurtzite phase of AlN was confirmed by x-ray diffraction and Rietveld analysis and Raman spectroscopy. Transmission electron microscopy was used to confirm the nanocrystallinity of AlN and to characterize the size distribution.
- A new method of making Aluminum Nitride from Nut Shells involving the formation of abundant quantities of MN from a thermal treatment of a mixture of aluminum oxide (Al2O3) and shells of almond, cashew, coconuts, pistachio, and walnuts in a nitrogen atmosphere at temperatures in excess of 1450° C.
- The following description and drawings set forth certain illustrative implementations of the disclosure in detail, which are indicative of several exemplary ways in which the various principles of the disclosure may be carried out. The illustrated examples, however, are not exhaustive of the many possible embodiments of the disclosure. Other objects, advantages and novel features of the disclosure will be set forth in the following detailed description when considered in conjunction with the drawings.
-
FIG. 1 illustrates X-ray diffraction patterns taken with CuKα radiation of AlN synthesized from Almond powder and aluminum oxide powder in nitrogen at a temperature of 1450° C. showing the wurtzite phase. -
FIG. 2A illustrates a TEM micrograph of AlN samples fabricated from almond showing the nanocrystalline nature. -
FIG. 2B illustrates a TEM micrograph of AlN samples fabricated from almond showing the nanocrystalline nature. -
FIG. 2C illustrates a TEM micrograph of AlN samples fabricated from walnut showing the nanocrystalline nature. -
FIG. 2D illustrates a TEM micrograph of AlN samples fabricated from walnut showing the nanocrystalline nature. -
FIG. 3 illustrates Raman Spectra of the AlN sample derived from almond confirming the wurtzite phase. -
FIG. 4A illustrates X-ray diffraction scan of Al2O3 mixed with almond showing peaks corresponding to corundum phase. The vertical lines correspond to the expected peaks of alumina. -
FIG. 4B illustrates a Rietveld whole profile analysis of the diffraction pattern for the AlN sample derived from almond after pyrolising in a nitrogen atmosphere followed by treatment in air at 800° C. -
FIG. 5A illustrates Raman spectra of AlN derived from pistachio showing the different Raman active modes. -
FIG. 5B illustrates Raman spectra of AlN derived from almond showing the different Raman active modes. -
FIG. 5C illustrates FTIR spectra of AlN derived from pistachio showing a broad band of 699 cm−1. -
FIG. 5D illustrates FTIR spectra of AlN derived from almond showing a broad band of 698 cm−1. -
FIG. 6 illustrates EDX of AlN derived from almond nut shell after pyrolysing in N2 and followed by heat treatment in O2 to remove excessive carbon. - A method of making Aluminum Nitride Synthesis from Nut Shells.
- Here, the inventors have discovered a method of forming pure AlN by carbothermal reduction of Al2O3 with raw nuts of almonds, coconuts, macadamia, pistachios, and walnuts in the presence of a N2 atmosphere to produce nano-tubes and nanoparticles previously not formed by other processing then purified in an O2 atmosphere in a Al2O3 crucible.
- The production process involves preparing samples from powders of raw nuts of almonds, coconuts, macadamia, pistachios, and walnuts after mixing them with nanocrystalline Al2O3 powder using ball milling with a SPEX 8000M including stainless steel milling media.
- The Al2O3 sample along with the specific nut shell was combined and milled to obtain a uniform powder. A hydraulic press was used to pressurize the homogenous powder into 1 cm diameter disks with a 2.5-3 mm depth.
- The pellets were heat treated (pyrolised) in a conventional furnace at temperatures exceeding 1400° C. for an interval of 5-6 hours in a nitrogen atmosphere.
- In order to eliminate the residual carbon, the pellets were then placed in air at 670° C.
- XRD scans were obtained using a Rigaku 18 kW rotating anode generator and a high resolution powder diffractometer. The diffraction scans were collected using monochromatic CuKα radiation.
- Raman spectra were collected on an inVia Raman Microscope (Renishaw) using a 514 nm laser line.
- Scans were obtained at ca. 15 mW laser power at the sample and an integration period of 30 seconds.
- Fourier Transform Infrared (FTIR) spectra were collected using Thermo Scientific Nicolet FT-IR spectrometer with Diffuse Reflectance Infrared Transform Spectroscopy (DRIFTS) accessory.
- In order to conduct the TEM analysis, ethyl alcohol was mixed with the pyrolyzed sample; the mixture was then set in an ultrasonic cleaner.
- A carbon covered 200 mesh copper grid was submerged into the mixture to collect AlN particles.
- A FEI Tecnai G2 TEM was utilized to examine the sample at 300 kV.
- Nuts have very little SiO2 uptake from the ground but still is a carbon source. Therefore nuts are a great candidate to mix with oxides to form a carbide and/or a nitride with further processing. The result is a pure nitride (in this case AlN) that is made in a simple cost effective process.
- AlN made from nuts such as almonds, pistachios, walnuts, cashew, coconuts, macadamia etc. can be made fully dense without the use of other dopants like AlN made in other ways. This provides a more pure bulk form of AlN.
- Due to its unique properties, it is extremely useful for the Navy. AlN its applications have been developed mainly for military aeronautics and transport fields.
- Other applications of AlN lie in refractory composites for handling of aggressive molten metals, and high efficiency heat exchange systems.
- The formation of pure AlN from nut shells offers a simple route as compared to complicated reactions currently being used involving carbon rich agents and at elevated temperatures.
- Moving to more environmentally greener processes is important. This process should become the standard processing for obtaining Pure AlN.
- The above examples are merely illustrative of several possible embodiments of various aspects of the present disclosure, wherein equivalent alterations and/or modifications will occur to others skilled in the art upon reading and understanding this specification and the annexed drawings. In addition, although a particular feature of the disclosure may have been illustrated and/or described with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Also, to the extent that the terms “including”, “includes”, “having”, “has”, “with”, or variants thereof are used in the detailed description and/or in the claims, such terms are intended to be inclusive in a manner similar to the term “comprising”.
Claims (6)
1. A nano-structured Aluminum Nitride (AlN) in a pure form and in the wurtzite phase of AlN from nut shells made from the steps of:
preparing powders of agricultural nuts using ball milling including stainless steel milling media;
preparing powders of nanocrystalline Al2O3 using ball milling including stainless steel milling media;
mixing the powders of agricultural nuts and the powders of nanocrystalline Al2O3 using ball milling including stainless steel milling media and thereby forming a homogenous sample powder of agricultural nuts and Al2O3;
pressurizing the homogenous sample powder of agricultural nuts and Al2O3 into a disk;
heat treating or pyrolizing the disk in a nitrogen atmosphere; and
reacting the disk and the nitrogen atmosphere and forming AlN;
wherein the AlN is nano-structured AlN and in a pure form and in the wurtzite phase of AlN.
2. The nano-structured Aluminum Nitride (AlN) in a pure form and in the wurtzite phase of AlN from nut shells of claim 1 further comprising the step of:
eliminating residual carbon by placing the disk in air after the step of reacting the disk and the nitrogen atmosphere and forming AlN.
3. The nano-structured Aluminum Nitride (AlN) in a pure form and in the wurtzite phase of AlN from nut shells of claim 2
wherein the step of heat treating or pyrolizing the disk comprises temperatures exceeding 1400° C. for an interval of 5-6 hours in a nitrogen atmosphere.
4. The nano-structured Aluminum Nitride (AlN) in a pure form and in the wurtzite phase of AlN from nut shells of claim 1
wherein the step of eliminating the residual carbon by placing the disk in air involves a temperature of 670° C.; and
wherein the step of heat treating or pyrolizing the disk comprises a conventional furnace.
5. A nano-structured Aluminum Nitride product from nut shells in a pure form and in the wurtzite phase from the steps comprising:
milling agricultural nuts into a fine nut powder;
milling nanocrystalline Al2O3 into a powder;
mixing the fine nut powder with the powder of nanocrystalline Al2O3;
pressing the fine nut powder and the powder of nanocrystalline Al2O3 into a pellet;
providing a nitrogen atmosphere;
heating the pellet to a temperature of about 1400° C.;
maintaining the temperature of the pellet at about 1400° C.;
cooling the pellet in air to a temperature of about 670° C.;
eliminating the residual carbon; and
forming nano-structures of AlN.
6. A nano-structured Aluminum Nitride product from nut shells in a pure form and in the wurtzite phase from the steps comprising:
milling agricultural nuts into a fine nut powder;
milling nanocrystalline Al2O3 into a powder;
mixing the fine nut powder with the powder of nanocrystalline Al2O3;
wherein the fine nut powder of agricultural nuts is prepared using ball milling with a SPEX 8000M including stainless steel milling media;
wherein the powder of nanocrystalline Al2O3 is prepared using ball milling including stainless steel milling media;
wherein the fine nut powder of agricultural nuts and the powder of nanocrystalline Al2O3 are mixed using ball milling including stainless steel milling media and thereby forming a homogenous sample powder of agricultural nuts and Al2O3;
pressing the fine nut powder and the powder of nanocrystalline Al2O3 into a pellet;
providing a nitrogen atmosphere;
heating the pellet to a temperature of about 1400° C.;
wherein the step of heating the pellet comprises a conventional furnace; and
wherein the step of pressing utilizes a hydraulic press;
maintaining the temperature of the pellet at about 1400° C.;
cooling the pellet in air to a temperature of about 670° C.;
eliminating the residual carbon; and
forming nano-structures of AlN;
wherein the AlN is nano-structured AlN and in a pure form and in the wurtzite phase of
wherein an 18 kW rotating anode generator and a high resolution powder diffractometer characterize the structure of the nano-structured AlN in a pure form and in the wurtzite phase with monochromatic CuKα radiation and further using a 514 nm laser line to obtain Raman spectra on an inVia Raman Microscope and scanning at about 15 mW laser power and an integration period of 30 seconds.
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US16/406,969 US20190261664A1 (en) | 2016-11-16 | 2019-05-08 | Aluminum Nitride Synthesis from Nut Shells |
US17/081,216 US11602158B2 (en) | 2016-11-16 | 2020-10-27 | Aluminum nitride synthesis from nut shells |
US18/118,921 US20230217971A1 (en) | 2016-11-16 | 2023-03-08 | Nano-structured Aluminum Nitride (AlN) in a pure form and in the wurtzite phase of AlN from nut shells |
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