Lubrication is a key element in a bearing’s performance and life. It aids in preventing wear and lowering friction, along with protection from extreme temperatures, corrosion and oxidation. Depending on individual applications, the lubricant can be oil, grease or next generation of film based technologies.
A recent advancement in film lubrication is set to greatly impact the bearing industry.
According to Design Fax, a new self-lubrication was discovered by coating a steel ring with catalytically active nanocotaing – tiny metal molecules that promote chemical reactions to break down other materials – and then placing it under high pressure and heat using a base oil without additives. After the test, the ring was fully intact without rust or surface damage, but with a dark deposit on the contact service. That deposit was an advanced diamond-like carbon (DLC).
Further tests revealed that this tribofilm reduced friction by 25-40 percent and wear was reduced to unmeasurable values. Plus, multiple types of catalytic coatings were found to produce DLC film.
How does it work?
It’s all about the tribofilm. The DLC is generated by breaking down molecules in the lubricating oil. It then regenerates the tribofilm as it is worn away by the application.
Design Fax reports that catalyst metals in the nanocomposite coatings strip hydrogen atoms from the hydrocarbon chains of the lubricating oil. It then breaks the chains into smaller segments. The smaller chains joined together under pressure to create the highly durable DLC tribofilm.
Basically, coatings interact with oil molecules to create the film, which adheres to the metal surface. When the film wears away, the catalyst in the coating is re-exposed to the oil, which develops new layers of tribofilm.
How will this affect the bearing industry?
Initially studied for targeted catalytic purposes, carry over to other industrial applications within the bearing industry is a natural progression. If the initial studies prove out over the long term, it will mean longer bearing design life, less maintenance and greater efficiency for bearings. Essentially, it will be a huge win for the industry.