Final answer:
The permanent breakdown of oil film strength occurs when the oil becomes too thin to effectively lubricate at high temperatures.
Step-by-step explanation:
The permanent breakdown of oil film strength occurs when an oil becomes too thin to effectively lubricate at high temperatures. This is caused by the decrease in viscosity, which is a measure of how resistant a liquid is to flow. At high temperatures, the oil molecules move faster and have more kinetic energy, causing them to separate more easily and reducing the oil film's ability to resist shearing forces.
This phenomenon is similar to thin film interference, where light waves interfere with each other when passing through a thin film, causing certain colors to be reflected or transmitted. In the case of oil, the thinning of the oil film results in a reduction in its ability to prevent metal surfaces from coming into contact and rubbing against each other, leading to increased friction and wear.
The permanent breakdown of oil film strength can also be influenced by factors such as the type of oil compounds present, the presence of oil-solubilizing prokaryotes in the ocean, and the temperature.