Friction, wear, lubrication – bases of nano-tribology

Nano-tribology is a sub-area of tribology. This science or technology describes and examines how two surfaces behave in a relative movement, and what practical processes are involved. Basically it comes down to friction and wear and therefore to the question of how to prevent the wear caused by lubricants or other procedures or at least how to slow it down in the long term. In terms of industry, it involves engines, gearboxes, roller bearings, guides and other movable machine elements. The bases of tribology go right back to the universal genius Leonardo da Vinci (1452-1519), who in his own lifetime, spent time among other things looking at the design of gears and gearboxes.

Nano-tribology examines the effects of friction at the nano-meter level and at the atomic level. In addition to the development of suitable lubricants, the main focus is on research on the selection of suitable materials, and the treatment and coating of surfaces. Nano-tribological relationships are of particular interest to industry. They can help to increase the energy efficiency of machines and at the same time reduce the cost of material use and maintenance. Important raw material resources are thus conserved and the environment protected. According to expert estimates, the cost of lubricants and wear caused by friction and abrasion in machines and gears is in the billions of Euro worldwide. Nano-tribology can help to reduce these costs significantly.

A nano-coating alters the surface structure of a material on a molecular level. On contact with the substrate, the nanostructures form a very thin, water and oil-repellent layer that is firmly bonded to the surface. In this way contamination from liquids, dust and other dirt is avoided. These properties are also known by the name "Lotus effect". The application is possible on almost any material and is especially suitable for fine-pore materials and applications that require high precision. A nano-coating can easily withstand temperatures up to 350 ° C.

Basically a nano-coating for machine parts can also be retrofitted, for example, in the case of a gearbox repair. However, it is not as durable, as it is when done directly in the production of machine parts. The nano-particles float in a solvent. As soon as this is evaporated by the action of heat and air, the nano-particles form a net-like structure, which is firmly connected to the surface of the treated parts. The components of the coating cause two things: They not only protect the underlying surface against mechanical stress from friction energy, for example in high loaded gear constructions, they also ensure with their added additives that foreign bodies cannot settle.

The question of the cost of a nano-coating is naturally one of the most important questions for any technical directors and managers of a company. We cannot give specific amounts at this point, as this depends on a variety of individual factors - the type of the particular machine or gearbox, the nature of the support material, the daily life and stress on the parts moving against each other. However, we can say that a nano-coating saves costs in the long term because it reduces the use of lubricants and increases the intervals of maintenance and repair works.

But existing plant, machinery and gearboxes can also be protected from wear and tear by the addition of certain lubricant additives. An example of this is the hitherto unique product portfolio of the company REWITEC^®. Designed and manufactured in Germany, the products are compatible with all standard lubricants, and can, on request, also be delivered in the customer’s lubricant. As an additive, they are added to the lubricant of the unit in the ongoing operation and transported by the lubricant to metal surfaces stressed by friction. There they use the friction energy and passivate the surfaces of bearings, gears and related components through the incorporation of silicates, reduce roughness, thereby sustainably and positively influencing the service life, power consumption, reliability and performance of gearboxes and roller bearings.

In addition to the cost, the question of the effects on health and the environment is an essential factor in the use of nano-coatings. According to the current state of research, coatings in the nano-range are not harmful to health nor do they pollute the environment. In fact, with their positive properties, they guarantee a safer working environment because they reduce the vulnerability of machines.