The usual catastrophic results of metal-oxygen fires lends impetus to the search for the fundamental mechanisms of metals combustion. A variety of experimental techniques and their subsequent analysis needs to be pursued. This paper analyzes the powder produced during NASA standard flammability experiments of zinc, vanadium, molybdenum, tungsten and silicon at pressures ranging from 3.44 MPa to 68.9 MPa. Each product powder has a distinctive shape and size distribution. These distributions are described and detailed. The effect of variation of oxygen pressure on these shapes and size distributions is reported. In addition, a qualitative description of the combustion mechanism and powder growth is suggested for each metal. In these experiments, the metals burned in heterogeneous reactions.
The oxygen compatibility of five O-ring formulations used in the Space Shuttle oxygen/hydrogen (O2/H2) fuel cell was evaluated following exposure to 450 and 6200 kPa (65 and 900 psi) oxygen at 121 °C (250 °F) for 48 h. The elastomers tested were Neoprene compound C873-70, and four fluoroelastomers: Aflas® 7182D, Kalrez® 1045, Fluorel® 2180, and compound V884-75. Post-aging changes in mass, dimension, tensile strength, elongation at break, durometer hardness, and compression set were determined for each elastomer. Aging results were compared to ignition and combustion data, namely the autogenous ignition temperature (AIT) and heat of combustion (ΔHc). Finally, the possibility of heterogeneous oxidation is discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.