Assertion: explosive's metal | /r/HasProperty | steel
Facets:
Source sentences:
text: It can be kept in some of the ordinary structural metals—steel, copper, aluminum, etc.—because of the formation of a thin film of insoluble metal fluoride that protects the bulk of the metal, just as the invisible coat of oxide on aluminum keeps it from burning up in the atmosphere.
text: NERA usually consists of two metal (steel, aluminium or titanium) layers with a confined/compressed layer of an elastic material such as rubber sandwiched inbetween.