prov:value
| - n, cobalt, beryllium, zinc, and tin; metal alloys such as steel, brass, bronze, boron carbide, and tungsten carbide, metal oxides such as zinc oxide, iron oxide, aluminum oxide, titanium oxide, magnesium oxide, and zirconium oxide; particulate carbonaceous materials such as graphite, carbon black, and natural bitumen; fly ash; or a hard particulate material as noted below, or the like, or combinat
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