5 Reasons Why Your Business Needs Graphene Grease？

In , Metcar began developing carbon/graphite materials and since then has developed hundreds of material grades suitable for use in industries ranging from aerospace to industrial.

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The carbon/graphite grades that have been developed have solved challenging lubrication problems where conventional grease and oil cannot perform and have proven to outperform other commonly used mechanical materials like PEEK, Teflon, and oilite in extreme environments. Carbon/graphite’s self-lubricating properties, chemical resistance, and high temperature resistance are some of the reasons that engineers choose to use carbon/graphite in their applications.

Opting to use carbon/graphite mechanical seals and bearings can have numerous benefits. In addition to being self-lubricating, Metcar’s material grades can have a combination of two or more of the properties tabulated below which combine to create a material grade that will help decrease down time due to bearing or seal failure.

1. High Temperature
Carbon/graphite can withstand extremely high temperatures. Metcar’s material is suitable for use within the following temperature ranges:

• 350 – ⁰F in oxidizing environments
• ⁰F in non-oxidizing environments

2. Low Temperature
Carbon/graphite can withstand cryogenic temperatures without failing. Metcar’s material is able to withstand -30 ⁰F to -450 ⁰F. At these temperatures, traditional lubricants and greases can congeal and solidify.

3. Dry Environment
No additional lubrication is needed for carbon/graphite parts in dry applications due to its self-lubricating properties. Graphene layers of graphite rub off during use to essentially have graphite running against itself. As a result, Metcar’s material will not seize or gall in these dry environments.

4. Wet Environment
Carbon/graphite parts are self-lubricating and do not require additional lubrication in submerged applications where oil and grease lubricants would be washed away. Furthermore, Metcar’s parts will not swell as a result of the wet environment.

5. Self-Lubrication
Metcar’s material requires no oil or grease in any environment. Graphite’s structure contains layers of carbon atoms (graphene) that are easily wiped off against a countersurface to provide lubrication.

This is beneficial for high or low temperatures where oil and greases will not suffice. Eliminating the need for oil and grease also eliminates down time due to maintenance requirements related to oiling.

6. Dimensionally Stable
Metcar’s materials have an exceptionally low coefficient of thermal expansion; meaning that the size and shape of the part does not drastically change with a change in temperature. As a result, the material is able to withstand extreme temperatures (high and low) without deforming.

7. Corrosion Resistant
Carbon graphite is chemically inert. As a result, many of Metcar’s materials are able to perform well in corrosive environments where metal would corrode.

8. Oxidation Resistant
Oxidation is a common problem faced when carbon comes in contact with oxygen. Metcar’s materials work to delay the onset of oxidation by protecting the surface carbon atoms with a salt impregnation.

This allows to extend service life of Metcar’s materials in demanding conditions by increasing temperature resistance.

• 350 – ⁰F in oxidizing environments
• ⁰F in non-oxidizing environments

9. Wear Resistant
Carbon graphite’s self-lubricating properties coupled with improved thermal properties (low coefficient of friction and high thermal conductivity) results in better performance without excessive wear.

10. Low Coefficient of Friction
Coefficient of friction (COF) is related to heat generation. As objects slide against each other, the kinetic energy is converted to thermal energy. Metcar’s materials have a low COF when running against a counterface. As a result, less heat is generated during use.

11. High Thermal Conductivity
Thermal conductivity is a measure of a material’s ability to conduct heat. Heat transfer occurs at a slower rate for materials with a low thermal conductivity. Metcar’s materials have a high thermal conductivity which allows heat that is generated due to friction to be transferred away from the contact point.

12. Food Safe
There are a variety of impregnations that have been declared as GRAS (Generally Recognized As Safe) by the FDA for use in sanitary or clean conditions such as the food, pharmaceutical, textile, paper, canning, and packaging industries.

Metcar also has material grades with the following approvals:

• NSF-51
• USP Class VI
• WRAS

13. Electrically Conductive
Metcar’s materials have excellent electrical conductivity; they eliminate static and will not spark. In addition, Metcar’s silver impregnated material grades have very low electrical noise, disturbances in an electrical signal, allowing the material to transmit signals clearly.

14. Run In Low Viscosity Fluids
Because low viscosity fluids are extremely thin, they can easily enter any available porosity of the material and create a blister on the material if the vaporize and expand within the porosity. Metcar’s material eliminates this possibility by offering material grades with zero available porosity.

In addition, Metcar’s materials are not atomically attracted to metals. Therefore, the thin hydrodynamic film that forms with low viscosity fluids is able to provide sufficient lubricating properties without risk of seizing or galling.

15. Run In Dry (Low Dew Point) Environments
Carbon graphite needs moisture to activate its self-lubricating properties. In applications with low dew point, Metcar offers carbon graphite grades with Molybdenum Disulfide which provides additional self-lubricating properties.

The properties of each particular material grade can vary. To find the material grade that is most suitable for your application, contact the Application Engineering Department at Metcar today.

Aleman Moil Product Page

Consider using carbon/graphite in your next pump application and contact an engineer at Metcar for assistance today.

By: Dr. Akanksha Urade (Graphene & 2D Materials Science Writer)

Graphene is increasingly being used as an additive to transform a growing number of products in practically every industry.
In this article, I will explore the use of graphene as a lubricant.

Why Graphene?

Graphene flakes have practically endless applications. It is added to other materials to improve strength, water resistance, flexibility and electrical conductivity. A tiny amount – typically, between 0.01%-0.5% – can produce dramatic improvements.

Graphene can be an inexpensive replacement for many incumbent materials.
The problem has been finding a reliable source for industrial volumes of the right quality graphene for specific applications.

Global Lubricant Market

Grandview Research predicts that the $130 billion lubricants business in will expand at a CAGR of 3.7% through , led by increasing global demand for higher-performance lubricants. Graphite is the primary incumbent material for lubricants. But graphite has a number of drawbacks – including that it only works in humid environments. Another disadvantage of graphite is the tendency of lamallae to rupture under severe mechanical loads, resulting in a limited lifetime and a higher coefficient of friction.

There are other problems with lubricants, including the use of ecologically hazardous additives or solid lubricants (such as molybdenum disulfide or boric acid). Both oil-based and solid lubricants do not bond well to the surfaces it lubricates and must be reapplied on a regular basis. Even under the best conditions, most lubricant oils eventually degrade over time due to oxidation.

Different forms of graphene have been extensively tested as a lubricant additive. Graphene’s use as a lubricant is attributed to a number of different physical-chemical properties. For example, graphene’s exceptional mechanical strength prevents material wear. Second, graphene has been demonstrated to be impermeable to liquids and gases like water and oxygen, slowing down the oxidative and corrosive processes that normally cause damage to rubbing surfaces. Furthermore, because graphene is an atomically smooth 2D material with low surface energy, it can replace the thin solid films that are typically used to reduce the adhesion and friction of various surfaces.

Graphene as an Additive in Oils

Graphene can also be utilized as an additive in lubricants to increase fuel economy and engine stability. Companies such as Graphenoil, Graphene-XT, HydroGraph, Versarien, NTherma and others have added different forms and quality of graphene to lubricating oil to enhance performance and stability, resulting in less wear and tear.

“The addition of graphene improves the oil’s tribological properties, making it more suitable for high-pressure, high-stress environments”, notes Simone Ligi, the Chief Executive Officer of Graphene-XT. “But the benefits of graphene do not stop there. Graphene has good heat transfer properties, essential to make lubricants safer at higher temperatures. All of these effects combined reduce engine noise and fuel consumption”.

Graphene as a Solid-State Lubricant

People commonly associate lubricants with the fluids found in automobiles and industrial machines. While fluids make up the vast majority of modern lubricants, a subset of lubricants known as solid-state lubricants also exists. Argonne National Lab has been researching solid lubricants based on graphene as a cheaper, more efficient and longer-lasting alternative to oil.

Image Courtesy: Berman, Diana, et al. Science ().

The use of graphene and carbon nanodiamonds as a solid-state lubricant to better preserve ball bearings is a field of study that has progressed rapidly in recent years, from an intriguing idea to a nearly practical reality. When graphene flakes and nanodiamond particles brush against a large diamond-like carbon (DLC) surface, the graphene encapsulates the nanodiamond by wrapping itself around it. As nanodiamonds are spherical in shape, the graphene-nanodiamond combination may travel freely between the two surfaces while providing lubrication. In addition to their lubricating and corrosion-preventative properties, they have also demonstrated super lubricity effects in which friction is reduced to nearly zero.

“That’s a significant improvement over any other existing solid lubricants coating available today,” says Argonne’s Prof. Anirudha V. Sumant. “Also, the amount of graphene needed is very small and therefore cost is much lower and eliminating oil waste would be more environmentally friendly, which is a great side benefit.”

The same research team revealed graphene to be an excellent steel lubricant. A few atomic layers of graphene not only reduce the degree of friction in steel rubbing against steel by seven times and the amount of wear by 10,000 times, but can also significantly lower the risk of corrosion.

The advantage of graphene-based solid lubricant coatings over standard lubricants is their simplicity of application. It is applied by spraying a solution over a vast surface area and can coat virtually any shape or size.

Graphene Oxide vs. Real Graphene

In our earlier piece titled “Fake Graphene: Let the Buyer Beware,” I made it abundantly clear that high-quality, defect-free graphene enjoys superior properties to their oxidized counterparts, such as graphene oxide (GO). However, in their marketing and on the labels of their bottles, many companies that sell GO and reduced graphene oxide (rGO) call these materials graphene. Even with lubricant applications, this is still the case.

Image courtesy: Berman, Diana, Materials Today ()

When compared to the wear rate of graphene layers, the wear rate of GO is between one and two orders of magnitude higher. As can be seen in the figure, oxidized graphene has dramatically inferior coverage compared to high-quality graphene, and the presence of oxygen in GO may cause corrosion of steel, which, in turn, increases wear. Because of this, GO does not offer anything approaching the same level of wear protection as high-quality graphene.

Conclusion

Contemporary lubricants contain ecologically hazardous chemicals or are solid lubricants (such as molybdenum disulfide or boric acid). Both oil-based and solid lubricants degrade over time and must be replenished on a regular basis. Real, high-quality graphene, on the other hand, can persist for a long period because the flakes realign themselves during initial wear cycles. Graphene, which is entirely composed of carbon, is environmentally friendly. In specific applications, do I think that graphene lubricants could serve as a suitable alternative to the more traditional oils and fluids? Yes. Would graphene lubricants be a universal replacement for oils? No. There are a number of reasons for this, but the key factor is the lack of supply of high-quality graphene. Nevertheless, we cannot deny that graphene-based lubricants and oils are making their way onto the market. However, whether or not they will come to dominate the market depends upon the ability to manufacture industrial volumes of high-quality graphene.

References

Berman, Diana, Ali Erdemir, and Anirudha V. Sumant. “Graphene: a new emerging lubricant.” Materials today 17.1 (): 31-42.

Berman, Diana, et al. “Macroscale superlubricity enabled by graphene nanoscroll formation.” Science 348. (): -.

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