General: Cleaning and Corrosion Control 🔊 Flashcards
What are the five common forms of corrosion?
(F-DISS) Fretting, dissimilar metal, intergranular, surface, and stress
Name at least three factors that influence corrosion.
Temperature, type of metal, availability of electrolytes and dissimilar metals, condition of protective coating
What are the two general conditions that may cause stress corrosion cracking?
Sustained tensile stress and corrosive environment
What is the cause of fretting corrosion?
When two mating surfaces which are normally at rest with respect to each other are subject to relative motion. Characterized by pitting of the surface and the generation of large quantities of fine debris. (smoking or mudding rivets)
What is the principal cause of filiform corrosion?
Surfaces that have not had the proper chemical treatment before painting
Where is intergranular corrosion most likely to occur?
Along the grain boundaries of extruded material
What is another name for dissimilar metal corrosion?
Galvanic corrosion
What are the factors which affect the type (form) of corrosion?
Atmospheric conditions, size and shape of the metal, the type of metal, and the corrosion producing agents present
What methods are used for removing rust from aircraft materials?
Abrasive paper and compounds, small power buffers and buffing compounds, hand wire brushes, and steel wool (except on highly stressed steel surfaces like oleo struts)
What is an acceptable method for removing surface corrosion from titanium?
Stainless steel brush, aluminum oxide sandpaper, scotch brite, abrasive blasting using glass bead, or hand polishing using aluminum polish and a soft cotton cloth
What specific operations are part of corrosion preventative maintenance?
Adequate cleaning, periodic lubrication, detailed inspection, prompt corrosion treatment, touch up paint, sealing, use of protective covers, and daily wipe down of exposed critical areas
Name the steps for corrosion removal.
Clean and strip the corroded area, remove as much corrosion as possible, neutralize any residual material remaining in pits and crevices, and restore protective surface films and paint.
What tools are approved for cleaning corroded anodized surfaces?
Fiber bristle brushes, aluminum wool, and aluminum wire brushes
What is used to keep corrosion from forming on aluminum alloy?
Oxide coating or aluminum cladding
What can be used to repair the anodized surface of an aluminum alloy part?
Alodine or other chemical conversion coatings
What products should be used to clean an aircraft engine?
A fine spray of kerosene or solvent
What should be used to clean grease, fuel, or oil from aircraft rubber tires?
Soap and water
Why should only recommended cleaners be used on aircraft fabric and plastics?
They cause less degradation of the materials
Name 5 areas of an aircraft that are more prone to corrosion.
Battery compartments, bilge areas, wheel wells and landing gear, flap recesses, lavatory, galley, and other areas where water might be entrapped
What form of corrosion can be found in battery compartments?
Direct chemical corrosion
Why are piano-type hinges prime locations for corrosion?
They use dissimilar metals (steel pins and aluminum hinges) and tend to trap contaminants between them
What is used to neutralize a lead-acid battery electrolyte?
A solution of baking soda and water
What is the difference between “wet wash” and “dry wash” aircraft cleaning?
Wet wash (water and an agent) removes oil, grease, carbon deposits, and soils, except for corrosion and oxide films. Dry wash (cloth or compressed air) removes film, dust, and small accumulations of dirt.
What are types of light duty and heavy duty aircraft cleaning agents?
Light duty are soap and synthetic detergents. Heavy duty are solvents and emulsion type cleaners.
What would you do before cleaning a wind screen?
Wet the surface to prevent scratching
What does filiform corrosion look like and where can it be found?
Thread or worm like puffiness of paint. It is found between the metal’s surface and the protective coating.
How is the inside of structural tubing prevented from corroding?
Coated in hot linseed oil
