Attorney Docket No.208273-0005-WO01 EXOTHERMIC REACTION MIXTURES CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to U.S. Provisional Patent Application No.63/563,133 filed on March 8, 2024, which is incorporated fully herein by reference. TECHNICAL FIELD [0002] This disclosure relates to exothermic reaction mixtures for use in, e.g., welding applications. INTRODUCTION [0003] Exothermic weld powders that can provide more effective thermite reactions can be useful for welding applications. SUMMARY [0004] In one aspect, disclosed are exothermic reaction mixtures comprising: an alloy, the alloy comprising copper (Cu) and aluminum (Al); and a metal oxide, the metal oxide comprising about 60% to about 75% Cu2O by mass of the mixture, and no more than 7.5% CuO by mass of the mixture. [0005] In another aspect, disclosed are exothermic reaction mixtures comprising: an alloy, the alloy comprising copper (Cu) and aluminum (Al); a metal oxide, the metal oxide comprising a mass ratio of Cu2O to CuO of about 9:1; CaSi2; CaF2 or LiF; and tin. [0006] In another aspect, disclosed are methods of welding, the method comprising: placing at least two components into a mold; adding an exothermic reaction mixture as disclosed herein to a crucible, the crucible being positioned on top of the mold; heating the exothermic reaction mixture to initiate an exothermic reaction that produces a liquid metal derived from the exothermic reaction mixture; and directing the liquid metal to contact the at least two components thereby joining the at least two components together. BRIEF DESCRIPTION OF THE DRAWINGS [0007] FIG.1 shows example thermite reaction equations for disclosed exothermic reaction mixtures.
Attorney Docket No.208273-0005-WO01 [0008] FIG.2 shows an example ceramic mold for use in the disclosed methods. As shown, a difference in the resulting viscosity of the molten weld metal and the liquified dross can cause the two to separate, where gravity can be used to fill a weld pocket in a mold. DETAILED DESCRIPTION [0009] Exothermic reaction mixtures (also referred to as exothermic weld powders) disclosed herein are formulated with synthetically produced copper oxides. Using synthetically produced copper oxides, rather than copper oxides sourced from copper mill scale, can achieve greater consistency and stability in the ratio of CuO to Cu2O within the mixture. This consistency and stability can allow the exothermic reaction mixture to be formulated as disclosed herein to provide increased copper yield of the thermite reaction, improved penetration when welding, and improved conductivity in the welded metal. 1. Definitions [0010] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting. Methods and materials similar or equivalent to those described herein can be used in practice or testing of the disclosed technology. All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. [0011] The terms “comprise(s),” “include(s),” “having,” “has,” “can,” “contain(s),” and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that do not preclude the possibility of additional acts or structures. The singular forms “a,” “and” and “the” include plural references unless the context clearly dictates otherwise. The present disclosure also contemplates other embodiments “comprising,” “consisting of” and “consisting essentially of,” the embodiments or elements presented herein, whether explicitly set forth or not. [0012] The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (for example, it includes at least the degree of error associated with the measurement of the particular quantity). The modifier “about” should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression “from about 2 to about 4” also discloses the range “from 2 to 4.” The
Attorney Docket No.208273-0005-WO01 term “about” may refer to plus or minus 10% of the indicated number. For example, “about 10%” may indicate a range of 9% to 11%, and “about 1” may mean from 0.9-1.1. Other meanings of “about” may be apparent from the context, such as rounding off, so, for example “about 1” may also mean from 0.5 to 1.4. [0013] For the recitation of numeric ranges herein, each intervening number there between with the same degree of precision is explicitly contemplated. For example, for the range of 6-9, the numbers 7 and 8 are contemplated in addition to 6 and 9, and for the range 6.0-7.0, the numbers 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are contemplated, and for the range 1.5-2, the numbers 1.5, 1.6, 1.7, 1.8, 1.9, and 2 are contemplated. [0014] Definitions of specific functional groups and chemical terms are described in more detail below. For purposes of this disclosure, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75th Ed., inside cover, and specific functional groups are generally defined as described therein. 2. Exothermic Reaction Mixtures [0015] Disclosed herein are exothermic reaction mixtures including an alloy, a metal oxide, and an optional additive. The exothermic reaction mixture can undergo a thermite reaction when, e.g., ignited by heat or a chemical reaction. During the thermite reaction, the mixture can react exothermically to generate a liquid metal and a slag. The generated liquid metal can then be used as a welding material to, e.g., join metallic components together. [0016] Exothermic welds derived from the exothermic reaction mixture can be produced using one of several thermite reactions. For example, see Equations (I) and (II): 2Al + 3CuO ^ Al2O3 +3Cu + 3CuO + 2Al (Equation I) 2Al + 3Cu2O
Al2O3 +6Cu + 3Cu2O+ 2Al (Equation II). Further details of example thermite reactions can be seen in FIG.1. [0017] The exothermic reaction mixture can also include a non-transition metal, a transition metal, an alloy of a non-transition metal, an alloy of a transition metal, an alloy of a transition metal and a non-transition metal, or a combination thereof. In some embodiments, the transition metal is copper (Cu). In some embodiments, the transition metal is a copper oxide or a combination of copper oxides. In some embodiments, the transition metal is copper (Cu), a copper oxide, a combination of copper oxides, or a combination thereof. [0018] The exothermic reaction mixture may include small to minimal amounts of other transition metals other than copper (Cu). For example, the exothermic reaction mixture may
Attorney Docket No.208273-0005-WO01 include a transition metal or combination of transition metals (e.g., nickel (Ni), cobalt (Co), iron (Fe), manganese (Mn), vanadium (V), molybdenum (Mo), or the like, or combinations thereof), other than copper (Cu), at no more than 10%, no more than 9%, no more than 8%, no more than 7%, no more than 6%, no more than 5%, no more than 4%, no more than 3%, no more than 2%, no more than 1%, no more than 0.5%, or no more than 0.1% by mass of the mixture. In some embodiments, the exothermic reaction mixture does not include another transition metal other than copper (Cu). For example, in some embodiments, the exothermic reaction mixture does not include nickel (Ni), cobalt (Co), iron (Fe), manganese (Mn), vanadium (V), molybdenum (Mo), or the like. [0019] The exothermic reaction mixture can have properties that make it useful for welding applications. For example, the exothermic reaction mixture can have a combustion temperature that is greater than a melting temperature of the alloy, less than a boiling point of the alloy, or both. In some embodiments, the exothermic reaction mixture has a combustion temperature that is greater than a melting temperature of the alloy and less than a boiling point of the alloy. In addition, the exothermic reaction mixture can have an increased density but still be able to yield a similar volumetric exothermic weld compared to less dense mixtures. A. Alloys [0020] The alloy can include copper (Cu) and aluminum (Al) and can act as a reducing agent in the exothermic reaction mixture. The alloy can include copper (Cu) and aluminum (Al) in varying amounts. For example, the alloy can include copper (Cu) and aluminum, individually, at about 47% to about 53%, such as about 48% to about 52%, or about 49% to about 51%. In some embodiments, the alloy includes no less than 47% copper (Cu), no less than 48% copper (Cu), no less than 49% copper (Cu), or no less than 50% copper (Cu). In some embodiments, the alloy includes no more than 53% copper (Cu), no more than 52% copper (Cu), no more than 51% copper (Cu), or no more than 50% copper (Cu). In some embodiments, the alloy includes no less than 47% aluminum (Al), no less than 48% aluminum (Al), no less than 49% aluminum (Al), or no less than 50% aluminum (Al). In some embodiments, the alloy includes no more than 53% aluminum (Al), no more than 52% aluminum (Al), no more than 51% aluminum (Al), or no more than 50% aluminum (Al). In some embodiments, the alloy includes equal amounts of copper (Cu) and aluminum (Al). The foregoing percentages in reference to copper (Cu) and aluminum (Al) of the alloy denote percentage by mass of the alloy. [0021] The exothermic reaction mixture can include copper (Cu) and aluminum (Al) in varying amounts. For example, the exothermic reaction mixture can include copper (Cu) and aluminum, individually, at about 8% to about 12%, such as about 9% to about 11%, or about 9%
Attorney Docket No.208273-0005-WO01 to about 10%. In some embodiments, the exothermic reaction mixture includes no less than 8% copper (Cu), no less than 8.5% copper (Cu), no less than 9% copper (Cu), or no less than 9.5% copper (Cu). In some embodiments, the exothermic reaction mixture includes no more than 12% copper (Cu), no more than 11% copper (Cu), no more than 10.5% copper (Cu), or no more than 10% copper (Cu). In some embodiments, the exothermic reaction mixture includes no less than 8% aluminum (Al), no less than 8.5% aluminum (Al), no less than 9% aluminum (Al), or no less than 9.5% aluminum (Al). In some embodiments, the exothermic reaction mixture includes no more than 12% aluminum (Al), no more than 11% aluminum (Al), no more than 10.5% aluminum (Al), or no more than 10% aluminum (Al). In some embodiments, the exothermic reaction mixture includes equal amounts of copper (Cu) and aluminum (Al). In some embodiments, aluminum (Al) is only included in the exothermic reaction mixture as part of the alloy. The foregoing percentages in reference to copper (Cu) and aluminum (Al) of the exothermic reaction mixture denote percentage by mass of the mixture. [0022] The exothermic reaction mixture can include varying amounts of the alloy. For example, the exothermic reaction mixture can include about 18% to about 24% of the alloy, such as about 19% to about 23% of the alloy, or about 20% to about 22% of the alloy. In some embodiments, the exothermic reaction mixture includes no less than 18% of the alloy, no less than 19% of the alloy, no less than 20% of the alloy, or no less than 21% of the alloy. In some embodiments, the exothermic reaction mixture includes no more than 24% of the alloy, no more than 23% of the alloy, no more than 22% of the alloy, or no more than 21% of the alloy. The foregoing percentages in reference to the alloy denote percentage by mass of the exothermic reaction mixture. [0023] The alloy can be a powder, e.g., in particulate form. The alloy can have a varying particle size making it useful for the exothermic reaction mixtures. For example, the size of the alloy particles can be important because suitable surface area and contact between the metals of the exothermic reaction mixture can ensure reactivity. The alloy can have an average particle size of about 100 µm to about 500 µm, such as about 105 µm to about 450 µm, about 110 µm to about 435 µm, about 100 µm to about 430 µm, about 100 µm to about 300 µm, about 300 µm to about 500 µm, or about 100 µm to about 475 µm. In some embodiments, the alloy has an average particle size of no less than 100 µm, no less than 105 µm, no less than 110 µm, or no less than 150 µm. In some embodiments, the alloy has an average particle size of no more than 500 µm, no more than 475 µm, no more than 450 µm, or no more than 430 µm. In some embodiments, the alloy particles are non-porous. In some embodiments, the alloy particles are
Attorney Docket No.208273-0005-WO01 non-spherical. Particle size and shape can be measured by techniques known within the art such as, but not limited to, laser diffraction and microscopy. B. Metal Oxides [0024] The metal oxide can be a copper oxide or a combination of copper oxides and can act as an oxidizing agent in the exothermic reaction mixture. In some embodiments, the exothermic reaction mixture only includes oxides of copper. The metal oxide can include Cu2O and CuO. In some embodiments, the metal oxide consists or consists essentially of Cu2O and CuO. The present application found that using synthetically made copper oxides and controlling the copper oxide ratios can provide weld mixtures with advantageous properties. Synthetic copper oxides can be made by heating copper (Cu) in a controlled environment to a specific ratio of CuO to Cu2O as opposed to taking the scale from the copper milling process. In some embodiments, the metal oxide is synthetically made. In some embodiments, the metal oxide is not sourced from a metal oxide mill scale, such as a copper mill scale. [0025] The exothermic reaction mixture can include Cu2O and CuO at varying amounts. For example, the exothermic reaction mixture can include about 60% to about 75% Cu2O, such as about 65% to about 75% Cu2O, about 67% to about 75% Cu2O, about 68% to about 74% Cu2O, about 70% to about 75% Cu2O, about 68% to about 74% Cu2O, or about 69% to about 73% Cu2O. In some embodiments, the exothermic reaction mixture includes no less than 60% Cu2O, no less than 65% Cu2O, no less than 66% Cu2O, no less than 67% Cu2O, no less than 68% Cu2O, no less than 69% Cu2O, or no less than 70% Cu2O. In some embodiments, the exothermic reaction mixture includes no more than 75% Cu2O, no more than 74% Cu2O, no more than 73% Cu2O, no more than 72% Cu2O, or no more than 71% Cu2O. The foregoing percentages in reference to Cu2O denote percentage by mass of the exothermic reaction mixture. [0026] In addition, the exothermic reaction mixture can include about 0% to about 7.5% CuO, such as about 0.5% to about 6% CuO, about 1% to about 5% CuO, or about 2% to about 4% CuO. In some embodiments, the exothermic reaction mixture includes no less than 0.5% CuO, no less than 1% CuO, no less than 2% CuO, or no less than 3% CuO. In some embodiments, the exothermic reaction mixture includes no more than 7.5% CuO, no more than 7% CuO, no more than 6% CuO, no more than 5% CuO, no more than 4% CuO, no more than 3% CuO, no more than 2% CuO, or no more than 1% CuO. The foregoing percentages in reference to CuO denote percentage by mass of the exothermic reaction mixture. [0027] The metal oxide can also include Cu2O and CuO at varying ratios. For example, the exothermic reaction mixture can include Cu2O and CuO at a mass ratio (Cu2O:CuO) of about
Attorney Docket No.208273-0005-WO01 3:1 to about 12:1, such as about 4:1 to about 11:1, about 5:1 to about 10:1, or about 6:1 to about 10:1. In some embodiments, the exothermic reaction mixture includes Cu2O and CuO at a mass ratio (Cu2O:CuO) of about 9:1. [0028] The metal oxide can include Cu2O and CuO at varying amounts. For example, the metal oxide can include about 90% to about 100% Cu2O, such as about 92% to about 100% Cu2O, about 93% to about 99% Cu2O, about 94% to about 97% Cu2O, or about 94% to about 100% Cu2O. In some embodiments, the metal oxide includes no less than 90% Cu2O, no less than 91% Cu2O, no less than 92% Cu2O, no less than 93% Cu2O, no less than 94% Cu2O, no less than 95% Cu2O, no less than 96% Cu2O, no less than 97% Cu2O, no less than 98% Cu2O, or no less than 99% Cu2O. In some embodiments, the metal oxide includes no more than 99% Cu2O, no more than 98% Cu2O, no more than 97% Cu2O, or no more than 96% Cu2O. The foregoing percentages in reference to Cu2O denote percentage by mass of the metal oxide. [0029] In addition, the metal oxide can include about 0% to about 10% CuO, such as about 0% to about 8% CuO, about 0% to about 5% CuO, about 0% to about 3% CuO, about 3% to about 7% CuO, or about 4% to about 6% CuO. In some embodiments, the metal oxide includes no less than 1% CuO, no less than 2% CuO, no less than 3% CuO, or no less than 4% CuO. In some embodiments, the metal oxide includes no more than 10% CuO, no more than 9% CuO, no more than 8% CuO, no more than 7% CuO, no more than 6% CuO, no more than 5% CuO, no more than 4% CuO, no more than 3% CuO, no more than 2% CuO, no more than 1% CuO, or no more than 0.5% CuO. The foregoing percentages in reference to CuO denote percentage by mass of the metal oxide. [0030] The exothermic reaction mixture can include varying amounts of the metal oxide. For example, the exothermic reaction mixture can include about 60% to about 85% of the metal oxide, such as about 60% to about 83% of the metal oxide, about 65% to about 83% of the metal oxide, about 65% to about 82% of the metal oxide, about 70% to about 80% of the metal oxide, about 73% to about 83% of the metal oxide, or about 75% to about 83% of the metal oxide. In some embodiments, the exothermic reaction mixture includes no less than 60% of the metal oxide, no less than 65% of the metal oxide, no less than 70% of the metal oxide, no less than 71% of the metal oxide, no less than 72% of the metal oxide, no less than 73% of the metal oxide, no less than 74% of the metal oxide, or no less than 75% of the metal oxide. In some embodiments, the exothermic reaction mixture includes no more than 85% of the metal oxide, no more than 84% of the metal oxide, no more than 83% of the metal oxide, no more than 84% of the metal oxide, no more than 83% of the metal oxide, no more than 82% of the metal oxide, no more than 81% of the metal oxide, no more than 80% of the metal oxide, no more than 79%
Attorney Docket No.208273-0005-WO01 of the metal oxide, no more than 78% of the metal oxide, no more than 77% of the metal oxide, no more than 76% of the metal oxide, or no more than 75% of the metal oxide. The foregoing percentages in reference to the metal oxide denote percentage by mass of the exothermic reaction mixture. [0031] The metal oxide can be a powder, e.g., in particulate form. The metal oxide can have a varying particle size making it useful for the exothermic reaction mixtures. For example, the size of the metal oxide particles can be important because suitable surface area and contact between the metals of the exothermic reaction mixture can ensure reactivity. The metal oxide can have an average particle size of about 250 µm to about 350 µm, such as about 250 µm to about 300 µm, about 300 µm to about 350 µm, or about 275 µm to about 325 µm. In some embodiments, the metal oxide has an average particle size of no less than 250 µm, no less than 275 µm, no less than 300 µm, or no less than 325 µm. In some embodiments, the metal oxide has an average particle size of no more than 350 µm, no more than 325 µm, no more than 300 µm, or no more than 275 µm. In some embodiments, the metal oxide particles are non- spherical. Particle size and shape can be measured by techniques known within the art such as, but not limited to, laser diffraction and microscopy. C. Additives [0032] The exothermic reaction mixture can include different additives to control properties such as, but not limited to, melting point, reduction over bronzing in the weld metal, and reduction of viscosity of dross materials. Example additives include, but are not limited to, a scavenging agent, a fluxing agent, a stabilizing agent, a buffering agent, and a combination thereof. In some embodiments, the exothermic reaction mixture includes a scavenging agent, a fluxing agent, and a stabilizing agent. In some embodiments, the exothermic reaction mixture includes a scavenging agent and a fluxing agent. In some embodiments, the additive consists of a scavenging agent, an optional fluxing agent, and an optional stabilizing agent. [0033] The exothermic reaction mixture can include a scavenging agent. A scavenging agent can prevent or minimize over bronzing in the weld metal (e.g., copper). The scavenging agent can become part of the slag and can be introduced to react with excess copper scale not reacted with the aluminum. This can improve the consumption of the available copper in the weld metal and can aid in the aluminum being the limiting agent in the overall thermite reaction. An example scavenging agent includes, but is not limited to, CaSi2. In some embodiments, the scavenging agent is CaSi2. [0034] The exothermic reaction mixture can include the scavenging agent at varying amounts. For example, the exothermic reaction mixture can include no more than 0.5% of the
Attorney Docket No.208273-0005-WO01 scavenger agent, no more than 0.75% of the scavenger agent, no more than 1% of the scavenger agent, no more than 1.1% of the scavenger agent, no more than 1.2% of the scavenger agent, no more than 1.3% of the scavenger agent, no more than 1.4% of the scavenger agent, no more than 1.5% of the scavenger agent, no more than 1.6% of the scavenger agent, no more than 1.7% of the scavenger agent, no more than 1.8% of the scavenger agent, no more than 1.9% of the scavenger agent, no more than 2% of the scavenger agent, no more than 2.5% of the scavenger agent, or no more than 3% of the scavenger agent. In some embodiments, the exothermic reaction mixture includes no less than 0.1% of the scavenger agent, no less than 0.5% of the scavenger agent, no less than 0.6% of the scavenger agent, no less than 0.7% of the scavenger agent, no less than 0.8% of the scavenger agent, no less than 0.9% of the scavenger agent, no less than 1% of the scavenger agent, no less than 1.1% of the scavenger agent, or no less than 1.2% of the scavenger agent. In some embodiments, the exothermic reaction mixture includes about 0.5% to about 3% of the scavenging agent, such as about 0.75% to about 2.5% of the scavenger agent, about 0.8% to about 2% of the scavenger agent, about 0.9% to about 1.8% of the scavenger agent, or about 1% to about 1.5% of the scavenger agent. The foregoing percentages in reference to the scavenging agent denote percentage by mass of the exothermic reaction mixture. [0035] The exothermic reaction mixture can include CaSi2 at varying amounts. For example, the exothermic reaction mixture can include no more than 0.5% CaSi2, no more than 0.75% CaSi2, no more than 1% CaSi2, no more than 1.1% CaSi2, no more than 1.2% CaSi2, no more than 1.3% CaSi2, no more than 1.4% CaSi2, no more than 1.5% CaSi2, no more than 1.6% CaSi2, no more than 1.7% CaSi2, no more than 1.8% CaSi2, no more than 1.9% CaSi2, no more than 2% CaSi2, no more than 2.5% CaSi2, or no more than 3% CaSi2. In some embodiments, the exothermic reaction mixture includes no less than 0.1% CaSi2, no less than 0.5% CaSi2, no less than 0.6% CaSi2, no less than 0.7% CaSi2, no less than 0.8% CaSi2, no less than 0.9% CaSi2, no less than 1% CaSi2, no less than 1.1% CaSi2, or no less than 1.2% CaSi2. In some embodiments, the exothermic reaction mixture includes about 0.5% to about 3% CaSi2, such as about 0.75% to about 2.5% CaSi2, about 0.8% to about 2% CaSi2, about 0.9% to about 1.8% CaSi2, or about 1% to about 1.5% CaSi2. The foregoing percentages in reference to CaSi2 denote percentage by mass of the exothermic reaction mixture. [0036] The exothermic reaction mixture can also include CaSi2 as measured by its relationship to the metal oxide and the alloy. For example, the exothermic reaction mixture can include a mass ratio of the metal oxide to a combination of the alloy and CaSi2 (metal oxide: combination of the alloy and CaSi2) of about 3:1 to about 9:2, such as about 3:1 to about 4.2:1,
Attorney Docket No.208273-0005-WO01 about 3.1:1 to about 4.1:1, about 3.5:1 to about 4:1, about 3:1 to about 3.8:1, or about 3.5:1 to about 9:2. [0037] The exothermic reaction mixture can include a fluxing agent. The fluxing agent can lower the melting point of the alloy and can improve cooling properties of the welds. The fluxing agent can be integrated within the lattice structure of the weld. However, too much fluxing agent can cause embrittlement and/or weaking of the resulting alloy. An example fluxing agent includes, but is not limited to, tin. In some embodiments, the fluxing agent is tin. In some embodiments, the fluxing agent is pulverized tin. [0038] The exothermic reaction mixture can include the fluxing agent at varying amounts. For example, the exothermic reaction mixture can include about 0% to about 3% of the fluxing agent, such as about 0.5% to about 2.8% of the fluxing agent, about 1% to about 2.5% of the fluxing agent, about 0% to about 2.3% of the fluxing agent, about 1.5% to about 2.5% of the fluxing agent, or about 1.8% to about 2.3% of the fluxing agent. In some embodiments, the exothermic reaction mixture includes no less than 0.1% of the fluxing agent, no less than 0.5% of the fluxing agent, no less than 1% of the fluxing agent, no less than 1.5% of the fluxing agent, or no less than 1.8% of the fluxing agent. In some embodiments, the exothermic reaction mixture includes no more than 2.5% of the fluxing agent, no more than 2.4% of the fluxing agent, no more than 2.3% of the fluxing agent, no more than 2.2% of the fluxing agent, no more than 2.1% of the fluxing agent, no more than 2% of the fluxing agent, no more than 1.9% of the fluxing agent, or no more than 1.8% of the fluxing agent. The foregoing percentages in reference to the fluxing agent denote percentage by mass of the exothermic reaction mixture. [0039] The exothermic reaction mixture can include tin at varying amounts. For example, the exothermic reaction mixture can include about 0% to about 3% tin, such as about 0.5% to about 2.8% tin, about 0.5% to about 2.5% tin, about 1% to about 2.5% tin, about 0% to about 2.3% tin, about 1.5% to about 2.5% tin, or about 1.8% to about 2.3% tin. In some embodiments, the exothermic reaction mixture includes no less than 0.1% tin, no less than 0.5% tin, no less than 1% tin, no less than 1.5% tin, or no less than 1.8% tin. In some embodiments, the exothermic reaction mixture includes no more than 2.5% tin, no more than 2.4% tin, no more than 2.3% tin, no more than 2.2% tin, no more than 2.1% tin, no more than 2% tin, no more than 1.9% tin, or no more than 1.8% tin. The foregoing percentages in reference to tin denote percentage by mass of the exothermic reaction mixture. [0040] The exothermic reaction mixture can include a stabilizing agent. The stabilizing agent can absorb heat during phase change, as well as can reduce the viscosity of dross materials, which can allow them to float to the top during welding. Example stabilizing agents include, but
Attorney Docket No.208273-0005-WO01 are not limited to, CaF2, LiF, and I2O5. In some embodiments, the stabilizing agent is CaF2, LiF, I2O5, or a combination thereof. In some embodiments, the stabilizing agent is CaF2 or LiF. [0041] The exothermic reaction mixture can include the stabilizing agent at varying amounts. For example, the exothermic reaction mixture can include about 0% to about 4% of the stabilizing agent, such as about 0.5% to about 3% of the stabilizing agent, about 1% to about 3.5% of the stabilizing agent, about 1% to about 4% of the stabilizing agent, about 0.5% to about 2% of the stabilizing agent, about 0.75% to about 1.8% of the stabilizing agent, about 1% to about 1.6% of the stabilizing agent, about 0.5% to about 1.5% of the stabilizing agent, or about 1% to about 2% of the stabilizing agent. In some embodiments, the exothermic reaction mixture includes no less than 0.5% of the stabilizing agent, no less than 0.75% of the stabilizing agent, no less than 1% of the stabilizing agent, no less than 1.1% of the stabilizing agent, no less than 1.2% of the stabilizing agent, no less than 1.3% of the stabilizing agent, no less than 1.4% of the stabilizing agent, or no less than 1.5% of the stabilizing agent. In some embodiments, the exothermic reaction mixture includes no more than 2% of the stabilizing agent, no more than 1.9% of the stabilizing agent, no more than 1.8% of the stabilizing agent, no more than 1.7% of the stabilizing agent, no more than 1.6% of the stabilizing agent, or no more than 1.5% of the stabilizing agent. The foregoing percentages in reference to the stabilizing agent denote percentage by mass of the exothermic reaction mixture. [0042] The exothermic reaction mixture can include CaF2 at varying amounts. For example, the exothermic reaction mixture can include about 0% to about 2% CaF2, such as about 1% to about 2% CaF2, about 1.2% to about 1.8% CaF2, about 1.3% to about 1.7% CaF2, about 1% to about 1.5% CaF2, or about 1.5% to about 2% CaF2. In some embodiments, the exothermic reaction mixture includes no less than 1% CaF2, no less than 1.1% CaF2, no less than 1.2% CaF2, no less than 1.3% CaF2, no less than 1.4% CaF2, or no less than 1.5% CaF2. In some embodiments, the exothermic reaction mixture includes no more than 2% CaF2, no more than 1.9% CaF2, no more than 1.8% CaF2, no more than 1.7% CaF2, no more than 1.6% CaF2, or no more than 1.5% CaF2. The foregoing percentages in reference to CaF2 denote percentage by mass of the exothermic reaction mixture. [0043] The exothermic reaction mixture can include LiF at varying amounts. For example, the exothermic reaction mixture can include about 0% to about 2% LiF, such as about 0.5% to about 2% LiF, about 0.75% to about 1.8% LiF, about 1% to about 1.6% LiF, about 0.5% to about 1.5% LiF, or about 1% to about 2% LiF. In some embodiments, the exothermic reaction mixture includes no less than 0.5% LiF, no less than 0.75% LiF, no less than 1% LiF, no less than 1.1% LiF, no less than 1.2% LiF, no less than 1.3% LiF, no less than 1.4% LiF, or no less
Attorney Docket No.208273-0005-WO01 than 1.5% LiF. In some embodiments, the exothermic reaction mixture includes no more than 2% LiF, no more than 1.9% LiF, no more than 1.8% LiF, no more than 1.7% LiF, no more than 1.6% LiF, or no more than 1.5% LiF. The foregoing percentages in reference to LiF denote percentage by mass of the exothermic reaction mixture. [0044] In some embodiments, the exothermic reaction mixture includes either CaF2 or LiF. In some embodiments, the exothermic reaction mixture includes about 1% to about 2% CaF2 or about 0.5% to about 2% LiF. D. Example Exothermic Reaction Mixtures [0045] In some embodiments, the exothermic reaction mixture consists of an alloy, the alloy including copper (Cu) and aluminum (Al); a metal oxide, the metal oxide including about 60% to about 75% Cu2O by mass of the mixture and no more than 7.5% CuO by mass of the mixture; and an optional additive selected from the group consisting of a scavenging agent, a fluxing agent, a stabilizing agent, a buffering agent, and a combination thereof. [0046] In some embodiments, the exothermic reaction mixture includes an alloy, the alloy including copper (Cu) and aluminum (Al); a metal oxide, the metal oxide including a mass ratio of Cu2O to CuO of about 9:1; CaSi2; CaF2 or LiF; and tin. [0047] In some embodiments, the exothermic reaction mixture includes, by mass of the mixture, about 20% to about 22% of the alloy, the alloy including copper (Cu) and aluminum (Al); about 67% to about 72% Cu2O; no more than 7.5% CuO; about 1% to about 2% CaSi2; and about 1% to about 5% CaF2. [0048] In some embodiments, the exothermic reaction mixture includes, by mass of the mixture, about 20% to about 22% of the alloy, the alloy including copper (Cu) and aluminum (Al); about 67% to about 72% Cu2O; no more than 7.5% CuO; about 1% to about 2% CaSi2; about 1% to about 5% CaF2; and about 0.5% to about 2.5% tin. [0049] In some embodiments, the exothermic reaction mixture includes, by mass of the mixture, about 20% to about 22% of the alloy, the alloy including equal amounts of copper (Cu) and aluminum (Al); about 68% to about 74% Cu2O; about 1% to about 5% CuO; about 1% to about 2% CaSi2; and about 1% to about 2% CaF2. [0050] In some embodiments, the exothermic reaction mixture includes, by mass of the mixture, about 20% to about 22% of the alloy, the alloy including copper (Cu) and aluminum (Al); about 68% to about 74% Cu2O; about 1% to about 5% CuO; about 1% to about 2% CaSi2; about 1% to about 2% CaF2; and no more than 2% tin. [0051] In some embodiments, the exothermic reaction mixture includes, by mass of the mixture, about 20.44% to about 22% of the alloy, the alloy including copper (Cu) and aluminum
Attorney Docket No.208273-0005-WO01 (Al); about 67.5% to about 71.25% Cu2O; no more than 7.5% CuO; about 1.5% to about 2% CaSi2; and about 1% to about 5% CaF2. [0052] In some embodiments, the exothermic reaction mixture includes, by mass of the mixture, an alloy including about 8.7% to about 10.6% aluminum (Al) and about 8.7% to about 10.6% copper (Cu); a metal oxide including about 67.5% to about 75% Cu2O; about 0% to about 7.5% CuO; about 1.5% to about 2% CaSi2; about 1.75% to about 2.5% CaF2 or about 0.5% to about 2.75% LiF; and about 0% to about 2.14% tin. E. Preparation of Exothermic Reaction Mixtures [0053] The alloy, the metal oxide, and the optional additive can be mixed together to provide the exothermic reaction mixture. Techniques known within the art can be used to mix the different components including, but not limited to, ball milling. In some embodiments, the mixing is done under an inert atmosphere. As discussed elsewhere herein, the alloy, the metal oxide, as well as the additive can be in powder form. The powder(s) can be passed through varying mesh sizes to get the appropriate particle size prior to and/or after mixing. In addition, the alloy, the metal oxide, and/or the additive can each, individually, have a purity of no less than 95% (e.g., includes no more than 5% impurities by mass of the component), no less than 96%, no less than 97%, no less than 98%, no less than 99%, or no less than 99.9%. In some embodiments, the alloy, the metal oxide, and/or the additive can each, individually, have a purity of no more than 100%, no more than 99.9%, no more than 99.8%, no more than 99.7%, no more than 99.6%, or no more than 99.5%. In some embodiments, the alloy, the metal oxide, and/or the additive can each, individually, have a purity of about 95% to about 100%, such as about 95% to about 99.9%, about 96% to about 99.9%, about 97 to about 99.9%, about 98% to about 100%, about 95% to about 98%, or about 97% to about 100%. The foregoing percentages in reference to purity level denote percentage by mass of the component being referenced. 3. Methods of Welding [0054] Also disclosed herein are methods of welding. The method can include placing at least two components into a mold. The number of components is not limited and the mold can be adapted for different shapes and number of components. The components can include metal (e.g., metal components). Example metallic components can include, e.g., copper, iron, and alloys thereof. The mold can include graphite or a ceramic. In some embodiments, the mold is graphite or a ceramic.
Attorney Docket No.208273-0005-WO01 [0055] The method can include adding the disclosed exothermic reaction mixture to a crucible. The exothermic reaction mixture can be provided as a powder or a pellet. In addition, the crucible can be positioned on top of the mold. An example crucible can be seen in FIG.2. The crucible can include graphite or a ceramic. In some embodiments, the crucible is graphite or a ceramic. The crucible can be a sacrificial crucible. The sacrificial crucible can include an inner lining that includes metals or alloy that are the same or compatible to that of a liquid metal produced by heating the exothermic reaction mixture. The sacrificial crucible can include an outer lining of refractory material. In addition, in embodiments where the exothermic reaction includes CaF2 rather than LiF2, the method can use a single use ceramic type mold. The use of LiF2 can result in a hard ceramic material called spudomene (Li-Al(SiO2)2) that may foul a graphite mold as it is a hard ceramic. [0056] The method can further include heating the exothermic reaction mixture to initiate an exothermic reaction (e.g., thermite reaction) that produces a liquid metal derived from the exothermic reaction mixture. Heating the exothermic reaction mixture can take place in the crucible and the resultant liquid metal can flow from the crucible per the direction of the mold. Heating can include a method of ignition having the requisite activation energy for a thermite reaction. In some embodiments, heating includes an energy greater than or equal to 94 kJ/mol, greater than or equal to 95 kJ/mol, greater than or equal to 100 kJ/mol, greater than or equal to 105 kJ/mol, greater than or equal to 110 kJ/mol, greater than or equal to 115 kJ/mol, or greater than or equal to 120 kJ/mol. An example method of heating includes the use of a gas torch such as an oxygen-propane torch, an oxygen-acetylene torch, or a methylacetylene propadiene stabilized (MPS) gas torch. Another example method of heating includes the use of resistance heating wires such as a tungsten resistance heating wire in an inert atmosphere (e.g., argon or nitrogen). [0057] The crucible can also include a heating element(s). For example, the crucible can include an outlet that includes a seal of the metal or alloy being used for the crucible wall (e.g., inner lining). The seal can prevent or mitigate the liquid metal from pouring out of the crucible until a predetermined time after the exothermic reaction mixture is heated. [0058] Heating the exothermic reaction mixture can also produce a slag. In some embodiments, the slag includes, by mass of the slag, about 0% to about 30% CaO (e.g., quickline); about 0% to about 64% SiO2 (e.g., silica); about 6% to about 83% Al2O3 (e.g., alumina); about 0% to about 3% CaF2 (e.g., fluorspar); about 0% to about 5% AlF3; about 0% to about 2% CaSi2; and about 0% to about 1% Ca2SiO4. In some embodiments, the slag includes, by mass of the slag, about 5% to about 30% CaO; about 12% to about 64% SiO2; about 6% to
Attorney Docket No.208273-0005-WO01 about 83% Al2O3; about 0% to about 3% CaF2; about 0% to about 5% AlF3; about 0% to about 2% CaSi2; and about 0% to about 1% Ca2SiO4. [0059] In embodiments where the exothermic reaction mixture includes a molar ratio of aluminum to CaSi2 of about 2:1, heating the exothermic reaction mixture can produce a slag including CaAl2Si2O8. [0060] In embodiments where the exothermic reaction mixture includes a molar ratio of aluminum to CaSi2 of about 10:1, heating the exothermic reaction mixture can produce a slag including Al2O3:CaAl2Si2O8 at a molar ratio of about 4:1. [0061] The method can also include directing the liquid metal to contact the at least two components thereby joining together the components in the mold. For example, the liquid metal can heat the at least two components to be joined and can bridge between the at least two components. In addition, the mold can be made with channel(s) that differ in number and arrangement that can effectively direct the liquid metal to the appropriate location, e.g., contacting the different components. [0062] The disclosed exothermic reaction mixture can provide advantageous properties to the method. For example, a copper yield of the exothermic reaction can be greater than or equal to 75%, greater than or equal to 80%, greater than or equal to 85%, greater than or equal to 90%, or greater than or equal to 95%. In addition, the conductivity of the joined components can be greater than or equal to 4 Ω, greater than or equal to 5 Ω, greater than or equal to 6 Ω, greater than or equal to 7 Ω, greater than or equal to 8 Ω, greater than or equal to 9 Ω, or greater than or equal to 10 Ω. [0063] Also, a resistance of the joined components can be about 4 µΩ to about 7 µΩ, such as about 4.5 µΩ to about 6.5 µΩ, about 5 µΩ to about 6 µΩ, about 4 µΩ to about 6 µΩ, or about 5 µΩ to about 7 µΩ. In some embodiments, the joined components have a resistance of no less than 4 µΩ, no less than 5 µΩ, or no less than 6 µΩ. In some embodiments, the joined components have a resistance of no more than 7 µΩ, no more than 6 µΩ, or no more than 5 µΩ. [0064] The disclosed technology has multiple aspects, illustrated by the following non-limiting examples. 4. Examples Example 1 Example Exothermic Weld Powder
Attorney Docket No.208273-0005-WO01 [0065] Step 1 – Establishing Base Components: The proportions of copper (I) oxide, and copper (II) oxide can be determined based on the formulated ratios of the two oxides in the “synthetic copper mill scale,” which is approximately 95% Cu2O and 5% CuO. The standard formulation by mass shall be a yield of 72 grams.9.0 grams of aluminum and 70.0 grams of synthetic copper oxide. The resulting mass of the weld metal will indicate the actual ratios of copper scale. [0066] Although the ratio of the oxides in the synthetic scale can be established by controlled processes, there can be deviation of 90% to 100 % for Cu2O and 0% to 10% percent for CuO. It can be beneficial to ensure that all of the copper oxide is reduced and turned to molten copper while at the same time trying to minimize the reactant’s (e.g., aluminum) bronzing effect on the provided weld alloy. The ratio can be determined by the amount of available heat and moisture during the copper milling process. [0067] Step 2 – Establishing Scavenging agents: Although this formulation has a 5% swing in deviation of copper oxide ratios, calcium silicide is introduced as a scavenger to ensure that all of the aluminum is consumed (to avoid bronzing) and that all of the copper oxides are reduced. Unreacted calcium silicide will end up in the slag as will any byproducts through its use as a fuel (scavenger). [0068] Step 3 – Establishing Fluxing and Drossing Agent: A heat sink that can be used is calcium fluoride (CaF2, fluoride or fluorspar). It has a relatively low melting point (1,402 °C or 1,675 °F), is inert (e.g., it doesn't take part in the reaction and doesn't decompose to any appreciable degree) and requires about 166 kJ per mol to melt and heat to 2,054 °C. Therefore, it can absorb some of the reaction heat, thereby reducing the end temperature of the mix somewhat. However, its relatively low melting point can also ensure that at the melting point of alumina, molten fluorite is highly fluid (low viscosity). For that reason, it can be referred to as a slag fluidizer. It can also form a relatively low melting eutectic with alumina. It is noted that unlike copper thermite reactions, cooling a manganese thermite sufficiently by slagging it with high amounts of CaF2 doesn't work because reaction kinetics are deleteriously affected, thereby impeding ignition or possibly leading to a fizzling mixture. [0069] Tin can be included into the formula as a fluxing agent. Its low melting point allows for a consistent heat transfer between the oxidizer and reducer transferring the necessary activation energy to maintain the reaction. Too much tin can cause embrittlement, and in steel applications, its use should be minimized. A version of the formula removes tin entirely for that reason. The bronzing effect of tin with respect to embrittlement begins at about 2% by mass therefore this is the maximum in the range of its use in this formulation.
Attorney Docket No.208273-0005-WO01 [0070] Step 4 – Calorimetric Considerations: The thermite reaction is similar to a nuclear reaction insofar as it is a chain reaction. Nuclear reactivity is controlled by regulating neutrons, thermite reactivity is controlled by regulating activation energy. The balance of heat in this thermite reaction can be controlled by the introduction of fluorspar (calcium fluoride). Another chemical considered is lithium fluoride. Both have a low melting point and high heat capacity. Both are inert. Fluorspar increases the electrical conductivity of alumina, and lowers the fusion temperature to around 1140 K. It also makes slag much easier to deal with. Fluorspar has a very low viscosity in a liquid state and is often used in iron smelting to decrease the viscosity of slag. It serves a dual purpose in this formulation. As a heat sink, but also to dissipate heat and lower the viscosity of the non-metallic elements. Example Calculations 2Al(s) + 3CuO(s) + ΔHea → Al2O3 (s) + 3Cu(l) + ΔH ΔHrxn = [(1)(ΔHp Al2O3) +(3)(ΔHp Cu)] - [(2)( ΔHr Al) + (3)(ΔHr CuO)] ΔHrxn = [(1)(-1669.8) +(3)(0) ] - [(2)(0) + (3)(-157.3)] ΔHrxn = -1669.8 + 471.9 = -1197.9 ΔHrxn = -1,197.9 Kj per mol Al2O3 2Al(s) + 3Cu2O(s) + ΔHea → Al2O3 (s) + 6Cu(l) + ΔH ΔHrxn = [(1)(ΔHp Al2O3) +(3)(ΔHp Cu)] - [(2)(ΔHr Al) + (3)(ΔHr Cu2O)] ΔHrxn = [(1)(-1669.8) +(3)(0) ] - [(2)(0) + (3)(-220.1)] ΔHrxn = -1669.8 + 660.3 =-1009.5 ΔHrxn = -1,009.5 Kj per mol Al2O3 2CaSi2 (s) + 10CuO(s) → Ca2SiO4+ 3SiO2 (s) + 10Cu(l) ΔHrxn = [(1)(ΔHp Ca2SiO4) + (3)(ΔHp SiO2) + (10)(ΔHp Cu)] - [(2)( ΔHr CaSi2) +(3)(ΔHr CuO)] 2CaSi2 (s) + 10Cu2O(s) → Ca2SiO4+ 3SiO2 (s) + 20Cu(l) ΔHrxn = [(1)(ΔHp Al2O3) +(3)(ΔHp Sio2) +(10)(ΔHp Cu)] - [(2)( ΔHr CaSi2) +(3)(ΔHr Cu2O)] CaF2 (s) → CaF2 (l) ΔH = (Molar Mass)(Cp ΔT)/1000 + ΔHlatent ΔH = [(78.07)(.83)(295.37-1691)]/1000 – 1186.1
Attorney Docket No.208273-0005-WO01 ΔH = 1276.53 Kj per Mol LiF (s) → LiF(l) ΔH = (MolarMass)(Cp ΔT)/1000 + ΔHlatent ΔH = [(25.94)(1.5)(295.37-732.03)]/1000 + 598.6 ΔH = 615.59 Kj per Mol Sn (s) → Sn(l) ΔH = (MolarMass)(Cp ΔT)/1000 + ΔHlatent ΔH = [(118.71)(.23)(295.37-505.05)]/1000 - 7.03 ΔH = 7.074 Kj per Mol TEST 1 Example Weld Powder Aluminum 9.25g = 9.25g/ (26.98g/mol) = 0.3428 Mols Copper 9.25g = 9.25g/ (63.55g/mol) = 0.1416 Mols Copper (I) Oxide 95.0% x 66.50g = 63.18g/ (143.09g/mol) = 0.4647 Mols Copper (II) Oxide 5.0% x 66.50g = 3.325g/ (79.55g/mol) = 0.0440 Mols PRIMARY REACTION (Limiting) 2Al + 3CuO → Al2O3 + 3Cu + 3CuO + 2Al + Cu 0.3428 0.0440 0.0147 0.0440 0.0000 0.3135 0.1416 SECONDARY REACTION (Limiting) 2Al + 3Cu2O → Al2O3 + 6Cu + 3Cu2O + 2Al + Cu 0.0314 0.4647 0.1549 0.9294 0.0000 0.0040 0.0000 (Copper) (Aluminum) Total 0.0440 0.040 0.1416 0.9294 1.1150 0.040 (70.86g) (1.080g) (71.94g) 9.25g Al 65.50g Cu-Syn 72.00 Actual Yield
Attorney Docket No.208273-0005-WO01 Example 2 Scavenging Agent [0071] Calcium silicide can be introduced as a secondary reduction agent because of the deviation in the oxides contained in the copper mill scale, and to ensure that all of the copper oxides are consumed, while maintaining that the aluminum can be the limiting reduction agent. In short, the aluminum is first consumed in the thermite reaction, and any leftover copper scale is consumed in an oxidation reduction reaction with calcium silicide. The amount of calcium silicide is based on the calculated deviation of aluminum in the “alumina” component of the weld powder (+/- 5%) and the deviation of copper oxides (+/-5% for CuO). The aluminum component can be as low as 8.325g. Aluminum 9.25g = 9.25g/ (26.98g/mol) = 0.3428 Mols Copper 9.25g = 9.25g/ (63.55g/mol) = 0.1416 Mols Copper (I) Oxide 95.0% x 66.50g = 63.18g/ (143.09g/mol) = 0.4647 Mols Copper (II) Oxide 5.0% x 66.50g = 3.33g/ (79.55g/mol) = 0.0440 Mol Calcium Silicide 2.00g = 2.00g/ PRIMARY REACTION (Limiting) 2Al + 3CuO → Al2O3 + 3Cu + 3CuO + 2Al + Cu 0.3428 0.0440 0.0147 0.0440 0.0000 0.3135 0.1416 SECONDARY REACTION (Limiting) 2Al + 3Cu2O → Al2O3 + 6Cu + 3Cu2O + 2Al + Cu 0.0314 0.4647 0.1549 0.9294 0.0000 0.0040 0.0000 TERTIARY REACTIONS (Limiting) 2CaSi2 + 10CuO → Ca2SiO4 + 3SiO2 + 10Cu (Limiting) 2CaSi2 + 10Cu2O → Ca2SiO4 + 3SiO2 + 20Cu Example 3 Drossing Effects and Fluxing Agents [0072] The use of tin allows for increased heat transfer between the copper oxide particles and the aluminum particles.
Attorney Docket No.208273-0005-WO01 [0073] Embrittlement. Amounts more than 2% tin (e.g., fluxing agent) by mass can lead to embrittlement, less than that and it can strengthen the weld with diminished concern of embrittlement. When the metallic molecules are ratioed within the resulting bronze alloy lattice structure it can weaken or strengthen the alloy based on the ratio of the two metals. Aluminum 9.25g = 9.25g/ (26.98g/mol) = 0.3428 Mols Copper 9.25g = 9.25g/ (63.55g/mol) = 0.1416 Mols Copper (I) Oxide 95.0% x 66.50g = 63.18g/ (143.09g/mol) = 0.4647 Mols Copper (II) Oxide 5.0% x 66.50g = 3.33g/ (79.55g/mol) = 0.0440 Mol Calcium Silicide 2.00g = 2.00g/ Calcium Fluoride 1.50g = (Lithium Fluoride) Pulverized Tin 2.00g = PRIMARY REACTION (Limiting) 2Al + 3CuO → Al2O3 + 3Cu + 3CuO + 2Al + Cu +ΔH 0.3428 0.0440 0.0147 0.0440 0.0000 0.3135 0.1416 SECONDARY REACTION (Limiting) 2Al + 3Cu2O → Al2O3 + 6Cu + 3Cu2O + 2Al + Cu 0.0314 0.4647 0.1549 0.9294 0.0000
MOLTEN METAL DROSS/SLAG 70.2 Actual Yield Example 4 Enthalpic Considerations [0074] Below is an enthalpic calculation of an example exothermic weld powder.
Attorney Docket No.208273-0005-WO01 Aluminum 9.25g = 9.25g/ (26.98g/mol) = 0.3428 Mols Copper 9.25g = 9.25g/ (63.55g/mol) = 0.1416 Mols Copper (I) Oxide 95.0% x 66.50g = 63.18g/ (143.09g/mol) = 0.4647 Mols Copper (II) Oxide 5.0% x 66.50g = 3.50g/ (79.55g/mol) = 0.0440 Mols Calcium Silicide 2.00g = 2.00g/ = Calcium Fluoride 1.50g = = Lithium Fluoride 1.00g = 5.25 (25.93g/mol) = 0.0385 Mols Pulverized Tin 2.00g = = PRIMARY REACTION (Limiting Agent) 2Al + 3CuO → Al2O3 + 3Cu + 3CuO + 2Al + Cu +ΔH 0.3428 0.0440 0.0147 0.0440 0.0000 0.3135 0.1416 SECONDARY REACTION (Limiting Agent) 2Al + 3Cu2O → Al2O3 + 6Cu + 3Cu2O + 2Al + Cu +ΔH 0.0314 0.4647 0.1549 0.9294 0.0000 0.0040 0.0000 TERTIARY REACTIONS (Limiting) 2CaSi2 + 10CuO → Ca2SiO4 + 3SiO2 + 10Cu +ΔH (Limiting) 2CaSi2 + 10Cu2O → Ca2SiO4 + 3SiO2 + 20Cu +ΔH INERT MATERIALS (Solid) (Liquid) CaF2 + ΔH → CaF2 Mols -1186.07 Kj/mol (Solid) 598.65 -598.65 (Liquid) LiF +1.507 J/g^°K -598.65 Kj/mol → LiF 0.0386 Mols [(0.0386 mols) (25.939 g/mol) (1.507 J/g^°K) (295.37-732.03)] /1000 + 0.0386 (-598.65 Kj/mol) = -23.766756 Kj (N) (Molecular Mass) Cp (Ti-Tf) /1000 + (N) ΔHl =ΔH MOLTEN METAL (Solid) (Liquid) Sn + ΔH → Sn Mols Kj/mol
Attorney Docket No.208273-0005-WO01 Example 5 Example Exothermic Weld Powder [0075] Listed below are components of an example exothermic weld powder. Synthetic copper oxide (95% Cu2O : 5% CuO by mass) 488 lbs Aluminum-Copper (50/50) alloy 125 lbs Calcium Silicide 7 lbs Fluorspar 4 lbs Pulverized tin 4 lbs [0076] It is understood that the foregoing detailed description and accompanying examples are merely illustrative and are not to be taken as limitations upon the scope of the disclosure. [0077] Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications, including without limitation those relating to the chemical structures, substituents, derivatives, intermediates, syntheses, compositions, formulations, or methods of use of the technology, may be made without departing from the spirit and scope thereof. [0078] For reasons of completeness, the following Embodiments are provided. [0079] Clause 1. An exothermic reaction mixture comprising: an alloy, the alloy comprising copper (Cu) and aluminum (Al); and a metal oxide, the metal oxide comprising about 60% to about 75% Cu2O by mass of the mixture, and no more than 7.5% CuO by mass of the mixture. [0080] Clause 2. The exothermic reaction mixture of clause 1, comprising an additive selected from the group consisting of a scavenging agent, a fluxing agent, a stabilizing agent, a buffering agent, and a combination thereof. [0081] Clause 3. The exothermic reaction mixture of clause 2, comprising a scavenging agent that is CaSi2. [0082] Clause 4. The exothermic reaction mixture of clause 3, comprising CaSi2 at no more than 1.5% by mass of the mixture. [0083] Clause 5. The exothermic reaction mixture of any one of clauses 2-4, comprising a fluxing agent that is tin. [0084] Clause 6. The exothermic reaction mixture of clause 5, comprising tin at no more than 2% by mass of the mixture.
Attorney Docket No.208273-0005-WO01 [0085] Clause 7. The exothermic reaction mixture of any one of clauses 2-6, comprising a stabilizing agent that is CaF2, LiF, I2O5, or a combination thereof. [0086] Clause 8. The exothermic reaction mixture of clause 7, comprising, by mass of the mixture: about 1% to about 2% CaF2; or about 0.5% to about 2% LiF. [0087] Clause 9. The exothermic reaction mixture of any one of clauses 1-8, comprising, by mass of the mixture, about 20% to about 22% of the alloy. [0088] Clause 10. The exothermic reaction mixture of any one of clauses 1-9, comprising, by mass of the mixture, about 60% to about 83% of the metal oxide. [0089] Clause 11. The exothermic reaction mixture of any one of clauses 1-10, comprising, by mass of the mixture: about 20% to about 22% of the alloy; about 67% to about 72% Cu2O; no more than 7.5% CuO; about 1% to about 2% CaSi2; and about 1% to about 5% CaF2. [0090] Clause 12. The exothermic reaction mixture of any one of clauses 1-11, wherein the alloy comprises, by mass of the alloy, about 47% to about 53% copper (Cu); and about 47% to about 53% aluminum (Al). [0091] Clause 13. The exothermic reaction mixture of any one of clauses 1-12, wherein the metal oxide comprises, by mass of the metal oxide, about 90% to about 100% Cu2O, and no more than 10% CuO. [0092] Clause 14. The exothermic reaction mixture of any one of clauses 1-13, comprising a mass ratio of the metal oxide to a combination of the alloy and CaSi2 of about 3:1 to about 9:2. [0093] Clause 15. The exothermic reaction mixture of any one of clauses 1-14, wherein the alloy is a powder having an average particle size of about 100 µm to about 500 µm. [0094] Clause 16. The exothermic reaction mixture of any one of clauses 1-15, wherein the metal oxide is a powder having an average particle size of about 250 µm to about 350 µm. [0095] Clause 17. The exothermic reaction mixture of any one of clauses 1-16, wherein the metal oxide is synthetically made. [0096] Clause 18. The exothermic reaction mixture of any one of clauses 1-17, wherein the mixture has a combustion temperature that is greater than a melting temperature of the alloy and less than a boiling point of the alloy. [0097] Clause 19. The exothermic reaction mixture of any one of clauses 1-18, comprising a non-transition metal, a transition metal, an alloy of a non-transition metal, an alloy of a transition metal, an alloy of a transition metal and a non-transition metal, or a combination thereof. [0098] Clause 20. The exothermic reaction mixture of clause 19, wherein the transition metal is copper (Cu).
Attorney Docket No.208273-0005-WO01 [0099] Clause 21. An exothermic reaction mixture comprising: an alloy, the alloy comprising copper (Cu) and aluminum (Al); a metal oxide, the metal oxide comprising a mass ratio of Cu2O to CuO of about 9:1; CaSi2; CaF2 or LiF; and tin. [00100] Clause 22. A method of welding, the method comprising: placing at least two components into a mold; adding an exothermic reaction mixture according to any one of clauses 1-21 to a crucible, the crucible being positioned on top of the mold; heating the exothermic reaction mixture to initiate an exothermic reaction that produces a liquid metal derived from the exothermic reaction mixture; and directing the liquid metal to contact the at least two components thereby joining the at least two components together. [00101] Clause 23. The method of clause 22, wherein the mold comprises graphite or a ceramic. [00102] Clause 24. The method of clause 22 or 23, wherein the exothermic reaction mixture is provided as a powder or a pellet. [00103] Clause 25. The method of any one of clauses 22-24, wherein the crucible comprises graphite or a ceramic. [00104] Clause 26. The method of any one of clauses 22-25 wherein a copper yield of the exothermic reaction is greater than or equal to 75% by mass of the mixture. [00105] Clause 27. The method of any one of clauses 22-26 wherein a conductivity of the joined components is greater than or equal to 4 Ω. [00106] Clause 28. The method of any one of clauses 22-27, wherein heating the exothermic reaction mixture produces a slag, the slag comprising, by mass of the slag: about 0% to about 30% CaO; about 0% to about 64% SiO2; about 6% to about 83% Al2O3; about 0% to about 3% CaF2; about 0% to about 5% AlF3; about 0% to about 2% CaSi2; and about 0% to about 1% Ca2SiO4. [00107] Clause 29. The method of any one of clauses 22-28, wherein heating the exothermic reaction mixture produces a slag, the slag comprising, by mass of the slag: about 5% to about 30% CaO; about 12% to about 64% SiO2; about 6% to about 83% Al2O3; about 0% to about 3% CaF2; about 0% to about 5% AlF3; about 0% to about 2% CaSi2; and about 0% to about 1% Ca2SiO4. [00108] Clause 30. The method of any one of clauses 22-29, wherein the exothermic reaction mixture comprises a molar ratio of aluminum to CaSi2 of about 2:1, and wherein heating the exothermic reaction mixture produces a slag comprising CaAl2Si2O8.
Attorney Docket No.208273-0005-WO01 [00109] Clause 31. The method of any one of clauses 22-29, wherein the exothermic reaction mixture comprises a molar ratio of aluminum to CaSi2 of about 10:1, and wherein heating the exothermic reaction mixture produces a slag comprising Al2O3:CaAl2Si2O8 at a molar ratio of about 4:1.