Definition 1 of 2
Definition
An anti-seize and anti-corrosion compound made by mixing petrolatum (petroleum jelly) with finely powdered zinc dust, applied to threaded fasteners and metal-to-metal joints to prevent galling, seizing, and corrosion. The zinc particles provide a sacrificial barrier against electrolytic corrosion, while the petrolatum carries the zinc and seals out moisture.
Plain English
A grease-like paste made of petroleum jelly mixed with fine zinc powder. It is smeared on bolts, fittings, and metal joints to keep them from rusting together or seizing up so they can be taken apart later.
Context Anchor
Seen in aircraft maintenance and repair instructions for protecting metal parts before assembly or after inspection.
Derivation
Petrolatum is the technical name for petroleum jelly, derived from petroleum (rock oil). Zinc is included as a fine dust because zinc corrodes preferentially to steel, protecting the underlying metal. Together the name describes exactly what is in the jar: petroleum jelly carrying zinc powder.
Why Pilots Care
Prevents hidden corrosion that can weaken structural components and fasteners, directly supporting continued airworthiness.
Intuition Check
Do not read “dust” as dirt or contamination here. It means intentionally added fine zinc powder mixed into a protective paste.
Example Sentence 1
The mechanic applied a thin coat of petrolatum-zinc dust compound to the exhaust stud threads before reinstalling the cylinder.
Example Sentence 2
During the annual inspection the technician reapplied Petrolatum-Zinc Dust Compound to the battery hold-down hardware.