Boron
Boron is a stable element, and can be oxidized to yield good heat output. The low atomic weight of boron (10.8) makes it an excellent fuel on a calories / gram basis. Boron has a high melting point (2300°C), and it can prove hard to ignite when combined with a high-melting oxidizer. With low-melting oxidizers, such as potassium nitrate, boron ignites more readily yielding good heat production. The low melting point of the oxide product (B 20 3 ) can interfere with the attainment of high reaction temperatures, however.
Boron is a relatively expensive fuel, but it frequently proves acceptable for use on a cost basis because only a small percentage is required (remember, it has a low atomic weight). For example, the reaction
burns well with only 5% by weight boron in the composition. Boron is virtually unknown in the fireworks industry, but is a widely-used fuel in igniter and delay compositions for military and aerospace applications.