LOW POWER HIGH-EFFICIENCY HEATING ELEMENT

Abstract

A heating element comprising a metal ribbon coated with heat resistant coatings adapted to produce radiant heat rapidly and with higher efficiency than prior known heating elements.

Claims

1. A heater element comprising an electrically conducting filament coated with at least the following substances: a hafnium compound and a zirconium compound.

2. The heater element of claim 1 wherein the electrically conducting filament is coated with at least hafnium diboride and zirconium diboride.

3. The heater element of claim 1 wherein the electrically conducting filament is coated with at least hafnium carbide and zirconium dioxide.

4. The heater element of claim 1 additionally coated with a tantalum compound.

5. The heater element of claim 4 wherein the tantalum compound is tantalum carbide.

6. The heater element of claim 1 additionally coated with a zirconium compound.

7. The heater element of claim 6 wherein the zirconium compound is selected from the group consisting of oxychlorides, hydrochlorides, orthosulphates and acetates.

8. The heater element of claim 6 wherein the zirconium compound is zirconium carbide.

9. The heater element of claim 1 coated with at least a hafnium compound, a zirconium compound and a tantalum compound.

10. The heater element of claim 8 coated with at least hafnium diboride and zirconium diboride and tantalum carbide.

11. The heater element of claim 2 wherein the electrically conducting filament is coated with at least hafnium diboride and zirconium diboride and is additionally coated with one of more compounds selected from the group consisting of: hafnium nitride (HfN), zirconium nitride (ZrN), titanium carbide (TiC), titanium nitride (TiN), thorium dioxide (ThO2) and tantalum carbide (TaC).

12. The heater element of claim 2 wherein the electrically conducting filament is additionally coated with one of more compounds selected from the group consisting of graphite, silica carbide, and yttrium aluminum garnet.

13. The heater element of claim 2 wherein the electrically conducting filament is additionally surrounded by a partial vacuum.

14. The heater element of claim 2 wherein the electrically conducting filament is additionally surrounded by a vacuum of less than 380 mm Hg.

15. The heater element of claim 2 wherein the electrically conducting filament is made of tungsten.

16. The heater element of claim 2 where the coatings consist of only hafnium diboride and zirconium diboride.

17. The heater element of claim 2 where the coatings consist of only hafnium carbide and zirconium dioxide.

18. The heater element of claim 2 where the coatings consist of only hafnium diboride and zirconium diboride and tantalum carbide.

19. The heater element of claim 2 where the coatings consist of only hafnium carbide and zirconium dioxide and tantalum carbide.

20. The heater element of claim 19 additionally surrounded by a vacuum of less than 380 mm Hg.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0038] FIG. 1 A schematic of a heating element wound around an insulated armature scaffold.

[0039] FIG. 2 Shows temperature and power vs time in seconds for low energy heater element.

[0040] FIG. 3 showing temperature and power vs time in seconds for NiCr heater element.

[0041] FIG. 4 showing temperature and power vs time in seconds for another NiCr heater element.

DETAILED DESCRIPTION OF THE INVENTION

[0042] The invention encompasses a heater element comprising an electrically conducting filament coated with at least the following substances: a hafnium compound and a zirconium compound. In preferred embodiments the heater filament is coated with at least hafnium diboride and zirconium diboride, for example with at least hafnium carbide and zirconium dioxide.

[0043] The heater element may be coated with at least hafnium diboride and zirconium diboride and additionally coated with one of more compounds selected from the group consisting of: hafnium nitride (HfN), zirconium nitride (ZrN), titanium carbide (TiC), titanium nitride (TiN), thorium dioxide (ThO2) and tantalum carbide (TaC). The filament may be additionally coated with one of more compounds selected from the group consisting of graphite, silica carbide, and yttrium aluminum garnet.

[0044] The filament may additionally be surrounded by a partial vacuum, for example by a vacuum of less than 380 mm Hg.

[0045] In various embodiments the invention is directed to electrical heating elements made from steel, copper, Nichrome, Iron-Chromium-Aluminum alloys, Cupronickel, and Platinum, and coated with at least the following: zirconium carbide, zirconium dioxide, hafnium carbide and tantalum carbide, and with various combinations of other heat-insulating and electrically-insulating materials.

[0046] In certain embodiments the invention encompasses a heater element made from a metal ribbon coated with chemical mixture of graphite and zirconia, or graphite and silica carbide, or other highly retractile, heat resistant insulating materials.

[0047] In certain embodiments, the present invention includes heating elements coated with hafnium diboride and zirconium diboride. In other embodiments the coatings may be one or more of graphite and/or silica carbide and/or hafnium carbide and/or tantalum carbide and/or titanium diboride and/or yttrium aluminum garnet in various combinations. In a specific embodiment, the present invention recites heating elements coated with at least (including but not limited to) the following: zirconium carbide, zirconium dioxide, hafnium carbide and tantalum carbide. It is believed by the applicant that this combination of coatings is unique and novel in the field of coating a heating filament, and has been selected for its effect on heat production using low energy input through a DC current.

[0048] The heater element of the invention has improved heat efficiency and can generate heat rapidly. The electricity conversion ration reaches almost 99.99% and the surface temperature on the heating element can be adjusted according to the design, surface area, length and structural design required.

[0049] The disclosed heater element is coated with chemical mixture of graphite and zirconia to ensure thermal lost is kept to below 0.2%. The heater design uses low voltage DC which is safer than AC and prevents short circuits.

[0050] Coatings. The metal ribbon is coated with highly retractile, heat resistant insulating materials. Such coatings may include ceramics, resins, zirconium, titanium dioxide, or chemical mixtures of graphite and zirconia, or graphite and silica carbide.

[0051] Zirconium is a preferred insulating coating and can be produced as a number of related compounds including oxychloride, hydrochloride, orthosulphate and acetates.

[0052] Ceramics like titanium dioxide and zirconium dioxide are good insulators and highly heat resistant and can be applied by dipping, spraying or painting onto a metal surface. Other ultrahigh temperature ceramic coatings that have proven thermal stability and excellent high-temperature mechanical properties may be used including hafnium carbide, tantalum carbide, or zirconium carbide, titanium diboride, yttrium aluminum garnet.

[0053] The heating element (filament) is generally any electrically conductive substance in the form of a ribbon, though may be a wire on any other shape including a plate or lattice, and is generally made from a ferrous metal such as steel, or a ferrous alloy, or a nickel-chromium alloy, a nickel-titanium alloy, an iron-chromium-aluminum alloy, an iron-chromium alloy, a cupronickel alloy, titanium, and platinum.

[0054] In the present disclosure, the heating filament may be surrounded by a chamber enclosing a vacuum. Partial vacuum refers to an air pressure of 50% or less of an atmosphere, which is 101,325 Pa (1,013.25 hPa; 1,013.25 mbar), equivalent to 760 mm Hg. Alternatively a vacuum of 75%, 25%, 10% or 5% or 1% of an atmosphere (or any range between these numbers) may be used. A standard vacuum of the invention may be from about 1000 mPa to 100 nPa. Ultra-high vacuum s may be used down to 10.sup.12 of atmospheric pressure (100 nPa). The chamber may be made of glass or any other suitable material. The vacuum will act as a thermal insulator, but heat will leave the filament via electromagnetic radiation, for example infa-red radiation.

[0055] A general embodiment of the invention encompasses a heating element coated (plated) with a combination of a graphite material (or graphene or other carbon-based material) and zirconia. The coating is chemically bonded to the heating element and is highly thermally insulating. When a DC current of, for example, 5 Amps is passed through the heating element, using a potential difference of 12 Volts, the element will reach about 1000 Degree Centigrade with a power input of, for example, 60 Watts.

[0056] In a typical embodiment, the heating element is made of a metal or metal alloy. For example, a nickel-chromium alloy.

[0057] In another embodiment, the heating element is made from a combination of an alloy of iron mixed with the nickel and chromium before the plating process. Other materials include nickel-titanium alloys, Nichrome, iron-chromium and aluminum alloys, cupronickel, titanium, palladium and platinum.

[0058] In other embodiments heating element may be made from any metal alloy that can achieve high temperatures without melting. Examples of nickel alloys and other high Temperature Alloys can be found at https://www.aircraftmaterials.com/datainickel/nickal.html#nickell

[0059] The disclosed heater element runs of DC power and uses much lower voltage compared to typical AC units. The present invention is more efficient and safer than the prior art, and the heating element can be heated to very high temperatures using only a few watts, for example 55 W-60 W, or in other embodiments, between 20 and 100 Watts, between 40 and 80 Watts or between 50 and 70 Watts.

[0060] The amperage of the DC current may be, for example, between 1 Amp and 50 Amps, or between 1 Amp and 50 Amps, or between 2 Amp and 40 Amps, or between 3 Amp and 30 Amps, or between 4 Amp and 20 Amps, or between 5 Amp and 10 Amps.

[0061] The voltage (potential difference) used may for example be between 1 and 120 Volts, 1 and 120 Volts, 4 and 90 Volts, 6 and 70 Volts, 8 and 50 Volts, 10 and 30 Volts, 12 and 25 Volts, or 12 and 15 Volts.

[0062] Of course, voltage and current change in direct relation to each other with the relationship V=IR when R is constant, and power used is proportional to the sum of the current and the voltage (P=IV; and P=I.sup.2R).

[0063] A typical embodiment of the invention is a heater element comprising a metal ribbon coated with an insulating compound selected from one or more of zirconia, or graphite and silica carbide. The metal ribbon may comprise a nickel-chromium alloy, a nickel-titanium alloy, an Iron-Chromium-Aluminum alloy, an iron-chromium alloy a cupronickel alloy, or titanium or platinum or other suitable metals.

[0064] In typical embodiments the metal ribbon achieves a temperature of at least 270 C. with a power input of no more than 60 W.

[0065] The heater element may, for example, have the following characteristics: the metal is a Nickel-Chromium alloy coated with a mixture of graphite and silica carbide, width between 1.0 and 6.0 mm, thickness between 0.2 and 0.6 mm, length between 100 and 400 mm, and resistance: 0.5-5.

[0066] A typical example of the heating strip of the invention is a ribbon made from a nickel-chromium alloy ribbon coated with a graphite and silica carbide coating with the following characteristics:

Total surface area=7946 mm2

Resistance=3.63

[0067] Strip length=903 mm
Strip thickness=0.4 mm
Strip width=4 mm
Input voltage=5V to 20V

[0068] For this typical example, temperature increases with power input with about 200 degrees centigrade achieved with an input of 60 Watts. 7 W=51 C., 10.02 W=51 C., 13.86 W=70 C., 17.84 W=88 C., 22.32 W=94 C., 27.7 W=110 C., 33.77 W=128 C., 39.12 W=145 C., 45.5 W=160 C., 52.08 W=176 C., 58.95 W=196 C., 66.5 W=221 C., 74.29 W=235 C., 82.8 W=275 C., 91.01 W=308 C., 100 W=315 C.

[0069] The heating element of the invention differs in several ways from a traditional heating element. First, of course, it is coated with a thermal insulator, second it has a larger surface area and a shorter length. It also has a lower resistance and will generally start to glow at >650 C.

[0070] Surface area for an application such as hair dryer may be for example about 2112 mm.sup.2, or between 1000 and 3000 mm.sup.2, or between 1500 and 2500 mm.sup.2, or between 1800 and 2200 mm.sup.2.

[0071] Width may be for example 4 mm, or between 1 and 10 mm, 2 and 7 mm, 3 and 5 mm.

[0072] Thickness may be for example 0.4 mm, or between 0.1 and 1 mm, or 0.2 and 0.8 mm, or 0.3 and 0.5 mm.

[0073] The length may be for example about 240 mm, or from 100 to 400 mm, from 150 to 300 mm or from 200 to 275 mm.

[0074] In one practical application, the invention provides for a a hand-held hair dryer comprising a heater element wrapped around an armature wherein a current is passed through the heating element to produce heat, wherein the heating element comprises a metal ribbon coated with a heat-insulating and non-electrically conductive compound, wherein the coating is selected from one or more of zirconia, or graphite and silica carbide, and the metal ribbon is formed from a substance selected from the group consisting of: a nickel-chromium alloy, a nickel-titanium alloy, an iron-chromium-aluminum alloy, an iron-chromium alloy, a cupronickel alloy, titanium, and platinum.

[0075] In a related embodiment, the hair dryer includes a metal ribbon that achieves a temperature of at least 100 C. with a power input of no more than 60 W.

[0076] In another related embodiment, the hair dryer operates to produce a constant and substantial flow or heated air sufficient to dry hair using a power input of no more than 60 W.

[0077] In another related embodiment, the hair dryer operates to produce a constant and substantial flow or heated air sufficient to dry hair using a power input of between 20 and 60 Watts.

[0078] Applicant is aware of a number of prior art references that disclose various heating elements, some of which are coated with various heat-resistant materials. For example Lo at al (U.S. Pat. No. 6,327,428), Manov et al. (U.S. Pat. No. 5,641,421), Etter (U.S. Pat. No. 3,029,360) and Pollak (US2002/0006275A1). Etter discloses coating of a heating wire with zirconium carbide. But it does not disclose a coating of graphite or silica carbide or hafnium carbide or tantalum carbide or titanium diboride or yttrium aluminum garnet or any combination of these elements as claimed in the present application.

EXAMPLES OF ASPECTS OF THE INVENTION

Example 1: Composition of Low Energy Heater Element

[0079] Element: Nickel-Chromium alloy and/or Iron Alloy

a. Coating: Chemical mixture of Graphite and Silica Carbide
b. Width: 4 mm
c. Thickness: 0.4 mm
d. Length: 240 mm
e. Total surface area: 2112 mm.sup.2
f. Volt DC: 12V
g. Current: 5 A
h. Resistance: 2
i. Power: 55 W-60 W
j. Temperature@ 60 W: 270 C.

Example 2: Low Energy Heater Element (Temp=Line Above; Watt=Line Below)

[0080] See FIG. 4 showing temperature and power vs time in seconds for low energy heater element.

Heater Strip Spec

[0081] Total surface area=7946 mm2 [0082] Volume=1444.8 mm3 [0083] Resistance=3.63 [0084] Strip length=903 mm [0085] Strip thickness=0.4 mm [0086] Strip width=4 mm [0087] Input voltage=5V to 20V

Example 3: 52.4 NiCr Heater Element (Temp=Line Above; Watt=Line Below)

[0088] See FIG. 5 showing temperature and power vs time in seconds for NiCr heater element.

NiCr Heater Wire Spec

[0089] Total surface area=2393 mm2 [0090] Volume=479 mm3 [0091] Resistance=52.4 [0092] Strip length=3808 mm [0093] Strip diameter=0.4 mm [0094] Input voltage=5V to 20V

Example 4: 20.3 NiCr Heater Element (Temp=Line Above; Watt=Line Below)

[0095] See FIG. 6 showing temperature and power vs time in seconds for NiCr heater element.

NiCr Heater Wire Spec

[0096] Total surface area=1267 mm2 [0097] Volume=253 mm3 [0098] Resistance=20.3 [0099] Strip length=2016 mm [0100] Strip diameter=0.4 mm [0101] Input voltage=5V to 20V

Example 5: Comparison of Low Energy Heater Element Vs. Traditional NiCr Heater Element

[0102]

TABLE-US-00001 LOW ENERGY HEATER ELEMENT NiCr HEATER ELEMENT BIG SURFAE AREA LOW SURFACE AREA SHORTER LENGTH USAGE LONGER LENGTH USAGE LOW RESISTANCE HIGH RESISTANE OPERATE IN DC OR AC VOLTAGE OPERATE IN AC VOLTAGE GENERATE HIGH HEAT AT LOW OHM GENERATE HIGH HEAT AT HIGH OHM ELEMENT START TO GLOW AT 650 C. ELEMENT START TO GLOW AT 250 C. LONGER DURABILTY LIFE OPTIMUM DURABILITY LIFE ENVIRONMENTAL FRIENDLY MATERIAL NON ENVIRONMENTAL FRIENDLY USE IN ALL TYPES OF ELECTRICAL APPL USE IN ALL TYPES OF ELECTRICAL APPL HIGH SAFETY DUE TO ABLE TO OPERATE IN DANGER OF ELECTROCUTION DUE TO AC DC VOLTAGE VOLTAGE

Example 6: Electric Consumption Comparison of Low Energy Heater Element Vs. Traditional NiCr Heater Element

[0103]

TABLE-US-00002 COMPARISON OF ELECTRICITY LOW ENERGY NiCr HEATER CONSUMPTION OF HAIR DRYER HEATHER ELEMENT ELEMENT DESCRIPTION VALUE VALUE Usage per day 8 hrs 8 hrs No of days use per month 25 days 25 days Average cost per KWh 0.3166 cent 0.3166 cent Power of heater element 60 W 1000 W Estimated usage per day(KWh) 0.40 kWh 6.67 KWh Estimated charge per day, RM RM0.13 RM2.11 Estimated charge per mth, RM RM3.80 RM63.32 5 PCS OF HAIR DRYER IN A HAIR SALOON, RM19 RM316.60 TOTAL ELECTRICITY PER MONTH

Further Examples of Commercial Aspects of the Invention

[0104] Some commercial embodiments include heating elements made from steel, copper, Nichrome, Iron-Chromium-Aluminum alloys, Cupronickel, and Platinum, and coated with at least a combination of the following: zirconium carbide, zirconium dioxide, hafnium carbide and tantalum carbide, and with various combinations of other heat-insulating and electrically-insulating materials.

[0105] In the present invention, important coatings include early transition metal borides such as hafnium diboride (HfB2) and zirconium diboride (ZrB2). Additional UHTCs under investigation for TPS applications include hafnium nitride (HfN), zirconium nitride (ZrN), titanium carbide (TiC), titanium nitride (TiN), thorium dioxide (ThO2), tantalum carbide (TaC) and their associated composites. Any of these may be used in the invention.

[0106] Various combinations include:

Zirconium dioxide only or non-exclusively. Zirconium carbide and zirconium dioxide only or non-exclusively. Zirconium carbide and zirconium dioxide and hafnium carbide only or non-exclusively. Zirconium carbide and zirconium dioxide and hafnium carbide and tantalum carbide only or non-exclusively. Hafnium carbide and tantalum carbide only or non-exclusively. Zirconium dioxide and hafnium carbide and tantalum carbide only or non-exclusively. Hafnium carbide only or non-exclusively. Tantalum carbide only or non-exclusively. Any of the above coatings may also include graphite or graphene or silica.

[0107] Other commercial embodiments include heater element made from a metal ribbon coated with chemical mixture of graphite and zirconia, or graphite and silica carbide, or other highly retractile, heat resistant insulating materials.

[0108] The heating elements of the invention require low power output and consume approximately 6% of the energy used by a conventional non-coated heating element which operates only on AC current. Additionally, use of DC current improves safety and transmission efficiency.

[0109] In certain commercial embodiments the filament is coated with graphene only about 1 atom in thickness.

[0110] Alternatively multiple layers of nano-carbon material may be laid over the heater element to achieve higher potential of energy efficiency at lower power input levels. Multiple layers of nano carbon material afford the safe & fast transfer of high powered energy. These commercial heating elements are particularly suitable for use in water heaters, boilers, plastic injection molding machines, heat flanging equipment, ovens, hot plates, home heaters, electric kettles, and wherever conventional heater elements are used.

Definitions

[0111] Zirconia: Zirconium dioxide, sometimes known as zirconia, is a white crystalline oxide of zirconium. A dopant stabilized cubic structured zirconia; cubic zirconia is synthesized in various colors for use as a gemstone and a diamond stimulant.

[0112] Graphene is a semi-metal with a small overlap between the valence and the conduction bands. It is an allotrope of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice. It is the basic structural element of many other allotropes of carbon, such as graphite, diamond, charcoal, carbon nanotubes and fullerenes.

[0113] Heating element: any component that functions to radiate or conduct heat to the environment such as a metal filament or ribbon, often wrapped around an armature. The heating element may also be in the form of a plate, or any other shaped component. Heating is provided by passing a current through the heating element.

[0114] Heat resistant: resisting heat up to at least 1000 degrees centigrade with no apparent physical deterioration.

[0115] Ribbon: refers to any elongated and flattened component with an approximately rectangular aspect ratio.

[0116] Armature: a non-electrically conducting scaffolding structure around which the heating element is wound.

[0117] In the present disclosure, a partial vacuum refers to an air pressure of 50% or less of an atmosphere, which is 101,325 Pa (1,013.25 hPa; 1,013.25 mbar), equivalent to 760 mm Hg. Alternatively a vacuum of 75%, 25%, 10% or 5% or 1% of an atmosphere (or any range between these numbers) may be used. A standard vacuum of the invention may be from about 1000 mPa to 100 nPa. Ultra-high vacuum s may be used down to 10.sup.12 of atmospheric pressure (100 nPa). Generally a low vacuum is considered to be 110.sup.5 to 310.sup.3 Pa, a medium vacuum is considered to be 310.sup.3 to 110.sup.1 Pa, and a high vacuum is considered to be 110.sup.1 to 110.sup.7 Pa. Any of these pressures or pressures between these, may be used in the invention.

GENERAL DISCLOSURES

[0118] This specification incorporates by reference all documents referred to herein and all documents filed concurrently with this specification or filed previously in connection with this application, including but not limited to such documents which are open to public inspection with this specification. All numerical quantities mentioned herein include quantities that may be plus or minus 20% of the stated amount in every case, including where percentages are mentioned. As used in this specification, the singular forms a, an, and the include plural reference unless the context clearly dictates otherwise. Thus, for example, a reference to a part includes a plurality of such parts, and so forth. The term comprises and grammatical equivalents thereof are used in this specification to mean that, in addition to the features specifically identified, other features are optionally present. For example, a composition comprising (or which comprises) ingredients A, B and C can contain only ingredients A, B and C, or can contain not only ingredients A, B and C but also one or more other ingredients. The term consisting essentially of and grammatical equivalents thereof is used herein to mean that, in addition to the features specifically identified, other features may be present which do not materially alter the claimed invention. The term at least followed by a number is used herein to denote the start of a range beginning with that number (which may be a range having an upper limit or no upper limit, depending on the variable being defined). For example, at least 1 means 1 or more than 1, and at least 80% means 80% or more than 80%. The term at most followed by a number is used herein to denote the end of a range ending with that number (which may be a range having 1 or 0 as its lower limit, or a range having no lower limit, depending upon the variable being defined). For example, at most 4 means 4 or less than 4, and at most 40% means 40% or less than 40%. Where reference is made in this specification to a method comprising two or more defined steps, the defined steps can be carried out in any order or simultaneously (except where the context excludes that possibility), and the method can optionally include one or more other steps which are carried out before any of the defined steps, between two of the defined steps, or after all the defined steps (except where the context excludes that possibility). When, in this specification, a range is given as (a first number) to (a second number) or (a first number)-(a second number), this means a range whose lower limit is the first number and whose upper limit is the second number. For example, from 40 to 70 microns or 40-70 microns means a range whose lower limit is 40 microns, and whose upper limit is 70 microns. When specific numbers are mentioned, it is implied that any range between these numbers may be used. For example if numbers 1, 5, 10 and 20 are mentioned, it is implied that ranges 1-20, 1-10, 1-5, 5-20, 5-20 etc. may also be used.

[0119] Note that when various coatings are listed in the, the invention also implicitly encompasses combinations of compounds including other compounds, OR lists of compounds EXCLUDING additional compounds, i.e., comprising the listed compounds.

REFERENCES

[0120] All the below references are incorporated by reference. [0121] Wuchina, E.; et al. (2007). UHTCs: ultra-high temperature ceramic materials for extreme environment applications. The Electrochemical Society Interface. 16: 30. [0122] Zhang, Guo-Jun; et al. (2009). Ultrahigh temperature ceramics (UHTCs) based on ZrB2 and HfB2 systems: Powder synthesis, densification and mechanical properties. Journal of Physics: Conference Series. 176 (1): 012041. Bibcode:2009JPhCS.176a2041Z. doi:10.1088/1742-6596/176/1/012041. [0123] Lawson, John W., Murray S. Daw, and Charles W. Bauschlicher (2011). Lattice thermal conductivity of ultra high temperature ceramics ZrB2 and HfB2 from atomistic simulations. Journal of Applied Physics. 110 (8): 083507-083507-4. Bibcode:2011JAP . . . 110h3507L. doi:10.1063/1.3647754. hdl:2060/20110015597. [0124] Monteverde, Frdric & Alida Bellosi (2004). Efficacy of HfN as sintering aid in the manufacture of ultrahigh-temperature metal diborides-matrix ceramics. Journal of Materials Research and Technology. 19 (12): 3576-3585. Bibcode:2004JMatR . . . 19.3576M. doi:10.1557/jmr.2004.0460. [0125] Zhao, Hailei; et al. (2007). In situ synthesis mechanism of ZrB2-ZrN composite. Materials Science and Engineering: A. 452: 130-134. doi:10.1016/j.msea.2006.10.094. [0126] Zhu, Chun-Cheng, Xing-Hong Zhang, and Xiao-Dong He. (2003). Self-propagating High-temperature Synthesis of TiC-TiB2/Cu Ceramic-matrix Composite. Journal of Inorganic Materials. 4: 026. [0127] Chen. T J (1981). Fracture characteristic of ThO2 ceramics at high-temperature. American Ceramic Society Bulletin. 60: 923. [0128] Curtis, C. E. & J. R. Johnson. (1957). Properties of thorium oxide ceramics. Journal of the American Ceramic Society. 40 (2): 63-68. doi:10.1111/j.1151-2916.1957.tb12576. [0129] Wang, Yiguang; et al. (2012). Oxidation Behavior of ZrB2-SiCTaC Ceramics. Journal of the American Ceramic Society. [0130] Sannikova, S. N., T. A. Safronova, and E. S. Lukin. (2006). The effect of a sintering method on the properties of high-temperature ceramics. Refractories and Industrial Ceramics. 47 (5): 299-301. doi:10.1007/s11148-006-0113-y.