Composite heat source for a smoking article

Abstract

A composite heat source for use in a smoking article is provided, including a non-combustible porous ceramic matrix; and a particulate combustible fuel embedded within the non-combustible porous ceramic matrix. The non-combustible porous ceramic matrix is formed from one or more particulate materials having a median D50 particle size at least five times less than the median D50 particle size of the particulate combustible fuel. Preferably, the non-combustible porous ceramic matrix includes one or more transition metal oxides.

1 .- 15 . (canceled) 
     
     
         16 . A composite heat source for a smoking article, comprising:
 a non-combustible porous ceramic matrix; and   a particulate combustible fuel embedded within the non-combustible porous ceramic matrix,   wherein the non-combustible porous ceramic matrix is formed from one or more particulate materials having a median D50 particle size at least five times less than the median D50 particle size of the particulate combustible fuel and wherein the volume fraction of the combustible fuel embedded in the non-combustible porous ceramic matrix is less than or equal to about 50% of the composite heat source.   
     
     
         17 . The composite heat source according to  claim 16 , wherein the non-combustible porous ceramic matrix comprises one or more oxides. 
     
     
         18 . The composite heat source according to  claim 17 , wherein the non-combustible porous ceramic matrix comprises one or more transition metal oxides. 
     
     
         19 . The composite heat source according to  claim 17 , wherein the non-combustible porous ceramic matrix comprises one or more oxides selected from the group consisting of: iron oxide; manganese oxide; zirconia; quartz; and amorphous silica. 
     
     
         20 . The composite heat source according to  claim 16 , wherein the non-combustible porous ceramic matrix has pores with diameters of between about 0.01 μm and about 10 μm. 
     
     
         21 . The composite heat source according to  claim 16 , wherein the non-combustible porous ceramic matrix has a thermal diffusivity of less than or equal to about 1×10 −6  m 2 /s. 
     
     
         22 . The composite heat source according to  claim 16 , wherein the combustible fuel has an oxidation enthalpy of greater than or equal to about 40×10 9  J/m 3 . 
     
     
         23 . The composite heat source according to  claim 16 , wherein the combustible fuel comprises carbon, aluminium, magnesium, one or more metal carbides, one or more metal nitrides, or a combination thereof. 
     
     
         24 . The composite heat source according to  claim 16 , further comprising at least one catalyst for the decomposition of a gas produced by combustion of the fuel. 
     
     
         25 . The composite heat source according to  claim 24 , wherein the at least one catalyst is embedded within the non-combustible porous ceramic matrix. 
     
     
         26 . The composite heat source according to  claim 16 , further comprising one or more oxidants. 
     
     
         27 . The composite heat source according to  claim 26 , wherein the one or more oxidants are selected from the group consisting of: nitrates; chlorates; perchlorates; and permanganates. 
     
     
         28 . The composite heat source according to  claim 16 , further comprising at least one airflow passageway. 
     
     
         29 . A smoking article, comprising:
 a composite heat source according to  claim 16 ; and   an aerosol-generating substrate.