Bonded thermite composition

Abstract

Thermite mixtures shaped or cast into a desired solid form and having sufficient structural integrity to withstand rough handling and challenging operating conditions, and methods of making such solid forms, are provided. When reacted, the thermite mixtures advantageously produce little or no offgas. The solid thermite forms may further include other materials that confer advantageous physical or chemical properties before, during, or after reaction of the thermite mixture.

1 . A bonded thermite composition, comprising:
 a thermite mixture, comprising a metal in a metallic form and a metal oxide; and   a glassy binding phase, comprising boron oxide other than the metal oxide.   
     
     
         2 . The bonded thermite composition of  claim 1 , wherein the metal is selected from the group consisting of aluminum, magnesium, silicon, manganese, an alloy of magnesium and aluminum, and combinations thereof. 
     
     
         3 . The bonded thermite composition of  claim 1 , wherein the metal oxide is selected from the group consisting of vanadium (V) oxide, iron (III) oxide, iron (II,III) oxide, copper (II) oxide, copper (I) oxide, tin (IV) oxide, titanium dioxide, manganese dioxide, manganese (III) oxide, chromium (III) oxide, cobalt (II) oxide, silicon dioxide, nickel (II) oxide, silver oxide, molybdenum trioxide, lead (II,IV) oxide, bismuth (III) oxide, and combinations thereof. 
     
     
         4 . The bonded thermite composition of  claim 1 , wherein the boron oxide comprises boron trioxide. 
     
     
         5 . The bonded thermite composition of  claim 1 , wherein the bonded thermite composition is substantially free of water and organic materials. 
     
     
         6 . The bonded thermite composition of  claim 1 , further comprising at least one fiber of an inorganic material. 
     
     
         7 . The bonded thermite composition of  claim 6 , wherein the inorganic material is selected from the group consisting of aluminum, silicon dioxide, and combinations thereof. 
     
     
         8 . The bonded thermite composition of  claim 1 , wherein the thermite mixture comprises from about 80% to about 120% of the stoichiometric amount of metal required for complete reaction with the metal oxide. 
     
     
         9 . The bonded thermite composition of  claim 1 , wherein the bonded thermite composition comprises from about 50 wt % to about 99 wt % of the thermite mixture and from about 1 wt % to about 50 wt % of the glassy binding phase. 
     
     
         10 . The bonded thermite composition of  claim 1 , having an equibiaxial strength of at least about 0.5 MPa. 
     
     
         11 . A method for making a bonded thermite composition, comprising:
 heat-treating a mixture of a thermite and a boron oxide precursor to form molten boron oxide, wherein the thermite comprises a metal in a metallic form and a metal oxide; and   cooling the mixture to solidify the molten boron oxide and form a glassy binding phase comprising boron oxide.   
     
     
         12 . The method of  claim 11 , wherein the boron oxide comprises diboron trioxide and wherein the boron oxide precursor is selected from the group consisting of diboron trioxide, boric acid, and combinations thereof. 
     
     
         13 . The method of  claim 11 , wherein, during the heat-treating step, the liquid boron trioxide facilitates liquid-phase sintering of at least one of the metal and the metal oxide. 
     
     
         14 . The method of  claim 11 , further comprising adding a solvent to the mixture. 
     
     
         15 . The method of  claim 14 , wherein the solvent is water. 
     
     
         16 . The method of  claim 14 , further comprising casting the mixture into a mold. 
     
     
         17 . The method of  claim 11 , wherein the thermite mixture comprises from about 80% to about 120% of the stoichiometric amount of metal required for complete reaction with the metal oxide. 
     
     
         18 . The method of  claim 11 , wherein the bonded thermite composition comprises from about 50 wt % to about 99 wt % of the thermite mixture and from about 1 wt % to about 50 wt % of the glassy binding phase. 
     
     
         19 . The method of  claim 11 , wherein the metal is selected from the group consisting of metallic aluminum, magnesium, silicon, manganese, an alloy of magnesium and aluminum, and combinations thereof. 
     
     
         20 . The method of  claim 11 , wherein the metal oxide is selected from the group consisting of vanadium(V) oxide, iron(III) oxide, iron(II,III) oxide, copper(II) oxide, copper(I) oxide, tin(IV) oxide, titanium dioxide, manganese dioxide, manganese(III) oxide, chromium(III) oxide, cobalt(II) oxide, silicon dioxide, nickel(II) oxide, silver oxide, molybdenum trioxide, and combinations thereof. 
     
     
         21 . The method of  claim 11 , wherein the mixture further comprises at least one fiber of an inorganic material. 
     
     
         22 . The method of  claim 21 , wherein the inorganic material is selected from the group consisting of aluminum, silicon dioxide, and combinations thereof. 
     
     
         23 . The method of  claim 11 , wherein the bonded thermite composition is substantially free of water and organic materials. 
     
     
         24 . The method of  claim 11 , wherein the bonded thermite composition has an equibiaxial strength of at least about 0.5 MPa. 
     
     
         25 . The method of  claim 11 , wherein the heat-treating step is carried out under an oxidizing or inert atmosphere. 
     
     
         26 . A method for limiting production of an offgas from a thermite reaction, comprising:
 providing a bonded thermite composition, comprising:
 a thermite mixture, comprising a metal in a metallic form and a metal oxide; and 
 a glassy binding phase, comprising boron trioxide; and 
   igniting the thermite mixture.   
     
     
         27 . The method of  claim 26 , wherein the offgas is selected from the group consisting of carbon monoxide, carbon dioxide, water, and combinations thereof and wherein the bonded thermite composition is substantially free of water and organic materials. 
     
     
         28 . The method of  claim 26 , wherein the metal is selected from the group consisting of metallic aluminum, magnesium, silicon, or manganese, an alloy of magnesium and aluminum, and combinations thereof, and wherein the thermite mixture comprises from about 80% to about 120% of the stoichiometric amount of metal required for complete reaction with the metal oxide. 
     
     
         29 . The method of  claim 26 , wherein the bonded thermite composition comprises from about 50 wt % to about 99 wt % of the thermite mixture and from about 1 wt % to about 50 wt % of the glassy binding phase. 
     
     
         30 . The method of  claim 26 , wherein the metal oxide is selected from the group consisting of vanadium (V) oxide, iron (III) oxide, iron (II,III) oxide, copper (II) oxide, copper (I) oxide, tin (IV) oxide, titanium dioxide, manganese dioxide, manganese (III) oxide, chromium (III) oxide, cobalt (II) oxide, silicon dioxide, nickel (II) oxide, silver oxide, molybdenum trioxide, lead (II,IV) oxide, and bismuth (III) oxide and combinations thereof. 
     
     
         31 . The method of  claim 26 , wherein the bonded thermite composition further comprises at least one fiber of an inorganic material. 
     
     
         32 . The method of  claim 26 , wherein the bonded thermite composition has an equibiaxial strength of at least about 0.5 MPa. 
     
     
         33 . The method of  claim 26 , wherein substantially no offgas is produced in the igniting step. 
     
     
         34 . A bonded composition, comprising:
 a metal in a metallic form; and   a glassy binding phase, comprising boron oxide.   
     
     
         35 . The bonded composition of  claim 34 , wherein the metal in a metallic form is part of a thermite mixture, wherein the thermite mixture further comprises a metal oxide other than boron oxide. 
     
     
         36 . The bonded composition of  claim 35 , wherein the metal oxide is selected from the group consisting of vanadium (V) oxide, iron (III) oxide, iron (II,III) oxide, copper (II) oxide, copper (I) oxide, tin (IV) oxide, titanium dioxide, manganese dioxide, manganese (III) oxide, chromium (III) oxide, cobalt (II) oxide, silicon dioxide, nickel (II) oxide, silver oxide, molybdenum trioxide, lead (II,IV) oxide, and bismuth (III) oxide, and combinations thereof. 
     
     
         37 . The bonded composition of  claim 35 , wherein the bonded composition is substantially free of water and organic materials. 
     
     
         38 . The bonded composition of  claim 35 , wherein the thermite mixture comprises from about 80% to about 120% of the stoichiometric amount of metal required for complete reaction with the metal oxide. 
     
     
         39 . The bonded composition of  claim 35 , wherein the bonded composition comprises from about 50 wt % to about 99 wt % of the thermite mixture and from about 1 wt % to about 50 wt % of the glassy binding phase. 
     
     
         40 . The bonded composition of  claim 35 , further comprising at least one fiber of an inorganic material. 
     
     
         41 . The bonded composition of  claim 40 , wherein the inorganic material is selected from the group consisting of aluminum, silicon dioxide, and combinations thereof. 
     
     
         42 . The bonded composition of  claim 34 , wherein the metal is selected from the group consisting of aluminum, magnesium, silicon, manganese, an alloy of magnesium and aluminum, and combinations thereof. 
     
     
         43 . The bonded composition of  claim 34 , wherein the boron oxide comprises boron trioxide. 
     
     
         44 . The bonded composition of  claim 34 , having an equibiaxial strength of at least about 0.5 MPa.