Listed items in this category relate to lubricants, chemicals & other consumables for different applications in aviation and other industries. Various lubricating tools, fittings & systems are also included in this category.
Lubricants are substances typically used to reduce friction between parts in contact but, depending on the type, they also perform various other functions such as heat regulation, power transmission, sealing against dust or dirt, as well as reducing oxidation and preventing corrosion. They come typically in liquid form (water, natural or synthetic oils), semi-solid form (greases), solid form (pastes) but also in other forms. Depending upon the application, one type of lubricant will work better then another. For intense friction and high-speed applications, oil-based lubricants are usually the best choice. However, for components that undergo heavy loads, or positioned or move vertically, these typically require a grease. Grease stays in place and provides a longer lasting barrier between components, such as wheel-bearings, nuts, bolts, etc. Some of the most commonly used lubricants are briefly presented below. Chemicals are sometimes termed also as lubricants but the term is most commonly used to denote surface preparation materials, paints and coatings, coolants, adhesives & sealants, cleaning products, fluids and others.
Oils
Oils are the most commonly used lubricants in manufacturing plants. Commonly used with gears, hinges, bearings, etc. They are suitable to use in high temperatures and high-speed applications. For oxidation and corrosion prevention, it is possible to use additives such as anti-oxidants or rust inhibitors with the base oil to enhance its properties. Base oil refers to the main ingredient that is present in most lubricants. Viscosity is an important parameter in the selection of oil. It refers to the nature of flow that oil exhibits at a specified temperature. To determine the viscosity for an oil, it is necessary to understand the two types of viscosity: dynamic viscosity (a measure of fluid’s resistance to flow) and kinematic viscosity (a measure of the velocity of fluid flow).
Greases
Greases are mixes of oil, thickener (soap), and additional lubricants (such as Teflon). The mix of these components provides grease with a different texture, thickness, and viscosity. Consistency is a defining attribute in the assessment of grease strength. It is greatly influenced by the viscosity of the base oil and the amount of thickener used. Selection of correct consistency is important in the lubricating application as soft greases can move away from the area of application while hard greases may not be able to properly move to reduce the effectiveness of lubrication. Greases generally exhibit similar lubricating properties as oils and they are used in applications where oils cannot be used or where the cooling attribute of the oil is not required. They provide excellent protection against wear and tear and provides excellent sealing against foreign particles. Often be used with gears, bearing, spindles, chains, linkages, etc.
Pastes
Pastes provide a similar working function as greases. However, they consist of a greater mix of solid lubricants resulting in their thick texture. The combined effect of base oil, thickeners (may or may not be included), and a solid lubricant such as PTFE protects against friction wear and tear. The addition of different solid lubricants makes the use of paste suitable in different types of applications.
Dry Lubricants
Dry lubricants are suitable when oils or greases cannot be used for lubrication purposes in extreme operating conditions such as vacuum, corrosive environment, or extreme temperatures. These can be classified into powdered form solid lubricants, sliding film, or bonded coatings and are usually available in spray form. They also can be mixed with water, alcohol, or other solvents.
Additives
Additives are organic or inorganic chemical compounds and consist important additions to the base oils enhancing the properties of lubricants.Most industrial applications include the following types of oil additives:
Antioxidant: To prevent oxygen from breaking down the lubricant and causing oxidation.
Extreme pressure: To increase lubricant’s ability to carry the load, for instance in gears and bearing.
Demulsifier: To enhance lubricants’ ability to repeal water.
Defoaming: To help in the breakup of foam bubbles.
Film strengtheners: To enhance the ability of lubricant film to attach to the surface.
Viscosity improver: To improve the viscosity of the lubricant at high temperatures.
Pour point: To decrease pour point temperature of lubricant in cold temperature. The pour point of an oil is measured to DIN ISO 3016. It lies a few degrees below the recommended lowest operating temperature.