Nano-additives found in high-performance lubricants have the ability to decrease carbon footprint, redefine operational efficiency, and promote a greener economy.
With scores of reports available on crucial property enhancement for different sizes, chemistries, and morphologies of nanoparticles, it is surprising to find a few companies that offer commercial nanolubricants. But what is the reason for the major gap that exists between basic tribology research and innovation?
In this context, Ducom Instruments has hosted a panel of experts to discuss the gap existing in tribology innovation. The group, which included Dr George Diloyan, CEO of Nanotech Industrial Solutions; Dr SSV Ramkumar, RnD Director, Indian Oil Corporation Limited; and Professor Jayashree Bijwe, Reliance Chair and Professor, Indian Institute of Technology, Delhi, shared its perceptions in a unique tribology discussions forum. MOOHA—A Digital Lab Assistant—has sponsored the forum.
According to the experts, the learnings and success stories, using PTFE and WS2 nanoparticles as examples, will provide a basic understanding of the reported “benefits” of nanolubricants.
The Contribution of Nano-Additive Lubricants to a Greener Economy
Nano-additives enable considerable friction reduction that enhances fuel economy and decreases energy losses. Lower friction (that is, lubricious IF-WS2) decreases heat generation and temperatures, resulting in less oxidation of oils and longer operating life.
Moreover, decreased wear results in longer drain intervals and fewer metal debris. Traditional extreme pressure (EP) and anti-wear (AW) additives also contain phosphorus and sulfur that are harmful to the environment and do not react sufficiently to form sacrificial compounds in slow-speed applications.
PTFE and Teflon are eco-friendly nanoparticles that can form films, fill in surface crevices, and prevent contact between metals.
Do All Nanolubricants Show Equal Performance? How to Select the Right Recipe
The selection of nano-additives is governed by chemistry, surface roughness, the physical mechanisms at the contacting interface, and end applications. Hollow IF-WS2 (inorganic fullerene) absorbs energy and deforms elastically when compared to MoS2 solid nanoparticle, therefore decreasing the propensity for micropitting under dynamic loading.
When compared to 2H MoS2, IF-WS2 forms adherent films by exfoliating gradually under increasing shear. In a few high-speed situations, the incorporation of nano-MoS2 in lithium greases may prove to be detrimental. Ultimately, even the most optimal spherical IF-WS2 cannot serve as nano-bearings if the surfaces are extremely rough and, therefore, cannot decrease friction.
When it comes to PTFE, the concentration, size, and base oil collectively play a major role. A phenomenal enhancement of 450% in EP loads is realized only for 70 nm particles at 3 wt%. Higher concentration and sizes are likely to agglomerate and cannot penetrate the contact zone to create surface films. In addition, only specific base oils with more polar groups can maintain the effectiveness and dispersion of nanoparticles.
To sum up, all nano-additives have certain benefits and drawbacks. Interpreting this factor in the context of the end applications helps identify the right solution.
How “Invention to Innovation” can Bridge the “Valley of Death” in the Development Cycle
Tribological characteristics, like antifriction (AF), EP, and AW, quantified in the laboratory have to translate to value proposition for customers, that is, better reliability, reduced consumption of energy, and overall savings.
Furthermore, upgrading bench-top experiments into industry-scale procedures definitely calls for major investments in resources and trust in the technology. Most often, this comes from many trials, experiments, and consistent data.
Early Association between industry partners and laboratory findings is very important to get the “voice of customer.” Most of the time, calculated risks have to be taken and full-field trials have to be performed based on the information produced from the bench-top tribotests. It is important to have the experience and understanding of critically assessing such tests.
High-quality precise scientific information forms the basis of such understanding and “faith” in inventions. In this context, the four ball tester from Ducom has the ability to distinguish the improved concentration and size of nanoparticles with slight modifications in chemistry and size. The potential to quantify temperature increase at the time of the test offered useful insights into the cooling characteristics of water-based IF-WS2 suspensions.
This information has been sourced, reviewed and adapted from materials provided by Ducom.
For more information on this source, please visit Ducom.