What is primarily formed due to tetraethyl lead in aviation gasoline when mixed with jet fuel?

The presence of tetraethyl lead in aviation gasoline can lead to the formation of deposits on turbine blades when mixed with jet fuel. Tetraethyl lead acts as an octane booster, which, while enhancing performance, can also result in the production of lead oxides and other compounds during combustion. These compounds can accumulate on hot engine surfaces, such as turbine blades, leading to the formation of hard, carbonaceous deposits. These deposits can impact engine performance by disrupting airflow, weakening the efficiency of the turbine, and potentially leading to maintenance issues.

In contrast, while carbon buildup in the engine might occur as a consequence of incomplete combustion, it's not specifically tied to tetraethyl lead in the context of jet fuel mixtures. Increased emissions could arise from various fuel compositions, not just tetraethyl lead, and higher fuel volatility is more a characteristic of the fuel itself rather than a direct effect of tetraethyl lead mixed with jet fuel. Thus, the accumulation of deposits on turbine blades is the most directly linked effect of tetraethyl lead in this scenario.