Metal dusting is a form of metal wastage commonly described as a surface or near-surface active phenomena where metals and alloys deteriorate in high temperature gaseous environments to form small particles of metal, oxides, carbides, and possibly carbon. This reaction leads to pitting and grooving of the attacked surface. High temperature apparatus was designed and constructed to study the metal dusting phenomena at various temperatures and in different carbonaceous gas environments on different stainless and nickel alloys. Metal loss, effects on metal surfaces and microstructure were reported. It was found that metal dusting behavior is greatly affected by both temperature and gas composition. Alloy performance also was affected by temperature.