No, I think it's real stuff. This is a fun website:

www.stardestroyer.net/Empire/Tech/Ground/Misc.html

Thermate grenades: these special-purpose grenades are (obviously) filled with a substance called thermate. Thermate is a powdered mixture of 1 part barium nitrate, 2 parts aluminum, and 3 parts iron oxide (rust). The aluminum and iron oxide particles are known as thermite, and when ignited by a very hot-burning fuse substance such as magnesium, the resulting incendiary reaction can easily melt steel. The burning liquid metal produced by the reaction has an accelerated heating/corrosion effect, and an M14 thermate grenade is said to be capable of burning a hole through a ½-inch thick steel plate. The addition of barium nitrate distinguishes thermate from thermite, and it allows the mixture to burn even when submerged underwater. Unlike the anti-personnel WP grenades, thermate grenades can be used to damage vehicles, small buildings, stored munitions, etc. The burning metal welds parts together, burns holes through plate, and distorts structural components. However, the area of destruction is quite small, so these grenades are not very widely used.