Which of the following contaminants is most detrimental when combined with water in lubricants?

The presence of metals like iron or copper in lubricants can be particularly detrimental when combined with water. This combination can lead to several adverse effects. Metals can promote corrosion processes when moisture is present, leading to the deterioration of metal surfaces and components. When water enters a lubricant, it compromises its ability to provide proper lubrication. If metals are also present, they can interact with the water and cause further degradation of the lubricant’s effectiveness, potentially leading to increased wear, deposits, and sludge formation.

Moreover, both iron and copper can engage in electrochemical reactions when combined with water, which can exacerbate rusting and compromise the integrity of machinery components. This can result in mechanical failures, decreased efficiency, and ultimately increased maintenance costs and downtime.

In contrast, while contaminants like dust may also affect lubricant performance, they do not typically induce the same level of chemical reactivity or localized corrosion seen with metals. Rust is an outcome of oxidation and does not contribute as directly to issues when mixed with water as metals do. Oil, when mixed with water, can lead to emulsification but does not create the same corrosive environment as metallic contaminants. Thus, the combination of water and metals like iron or copper poses a particularly high risk and can lead to significant operational