Abstract: In the operation of aviation gas turbine engines using some hydrocarbon fuels, pitting corrosion on heat resistant Ni-Cr alloy parts in the combustion chamber has been observed.Experiments indicate that the pitting corrosion is not caused by impurities in the fuel but by the hydrocarbons. Investigation of the effect of various gas components on the heat resistant Ni-Cr alloys and nickel, of the carbon deposits formed on the alloy surface and of the changes in alloy composition of the attacked parts reveals that the bulk alloy is attacked by the burning hydrocarbons containing methane and carbon monoxide through carburization of the alloy which give rise to the precipitation of chromium carbides and the formation of nickelrich spots. As a consequence of the catalytic action of nickel on hydrocarbons, dehydrocondensation reactions take place and the corroded surface is readily covered with carbon by graphitizing action. It is theorized that pitting corrosion of the Ni-Cr alloys occur through these processes. It can be inhibited by the addition of some sulfur, arsenic or selenium compounds into the fuels to hinder the undesired catalytic dehydrocondensation reactions.