US Patent 10440990 Composite heat source for a smoking article

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.