Formation of carbides and hydrocarbons in chondritic interplanetary dust particles: A laboratory study

The reaction between kamacite grains and H-2 + CO gas mixture has been tested in the laboratory under experimental conditions presumed for interplanetary dust particle (IDP) formation in a nebular-type environment (H-2:CO = 250:1; 5 x 10(-4) atm total pressure, and 473 K). Carbon deposition, hydrocarbon production in the C-1-C-4 range, and the formation of an E-carbide phase occur when well-defined model FeNi bcc alloy (kamacite) particles are exposed to a mixture of H-2 + CO during 10(3) h. These results strongly support the idea that gas-solid reactions in the solar nebula during CO hydrogenation represent a plausible scenario for the formation of carbides and carbonaceous materials in IDPs, as well as for the production of hydrocarbons through Fischer-Tropsch-type reactions.