Antiwear additive

Titanium compounds could be used as an environmentally friendly additive for automotive oil, according to materials scientists from Afton Chemical Corporation and the National Institute of Standards and Technology (NIST).

In a recent study, the researchers established that a titanium compound added to engine oil creates a wear-resistant nanoscale layer bound to the surface of vulnerable engine parts, making it a credible substitute for older compounds.

Modern engine lubricating oil is a complex, highly engineered mixture, up to 20 per cent of which may be special additives to enhance properties such as viscosity and stability and to reduce sludge formation and engine wear.

For years, antiwear additives for high-performance oils have been phosphorous compounds, particularly zinc dialkyldithiophosphate, or ZDDP, that work by forming a polyphosphate film on engine parts that reduces wear.

Unfortunately phosphorus is a chemical poison for automobile catalytic converters, reducing their effectiveness and life span, so industry chemists have been searching for ways to replace or reduce the use of ZDDP. It is not a simple problem because the additive has several useful functions in addition to wear resistance.