Activated Carbon Nano-Particles from Recycled Polymers Waste as a Novel Nano-Additive to Grease Lubrication

Abstract

A worldwide growing trend is dedicated towards reducing carbon dioxide emissions from mechanical systems in different industries. One key factor under focus of research is to decrease energy losses in rotating machinery during operation by improving lubrication performance. This paper presents a novel grease nano-additive using activated carbon (AC) as a byproduct from recycled polymer waste. Five different concentrations of AC nanoparticles (ACNPs) are added to lithium grease to obtain blends containing 0.025 wt.%, 0.05 wt.%, 0.1 wt.%, 0.5 wt.%, and 1 wt.%. The tribological assessment of blends has been performed using a four-ball wear test and load carrying capacity test. The obtained results for blends are compared to samples of base grease and to blends with 2 wt.% reduced graphene oxide (rGO). Test results showed a remarkable enhancement of load carrying capacity of AC samples by 20–30% as compared to base grease. By observing wear scar in rolling elements, the ACNPs lowered the average wear scar diameter (WSD) for all samples by 30–36%. Base grease samples showed the highest coefficient of friction (COF) values between 0.15 and 0.17. These values are reduced to 0.03 and 0.06 for grease with ACNPs reaching their minimum in the case of 1 wt.% AC. These outcomes are found consistent with the enhancements in driving power saving values. The results proved the competitiveness and suitability of the AC as a recycled waste and nano-additive for improving the tribological performance of grease lubrication.

Tribological and Physicochemical Behavior of a Novel Palm Grease Blended with Zinc Oxide and Reduced Graphene Oxide Nano-Additives

“…Load carrying capacity of each grease blend is determined using a tailored test setup based on Brugger's test machine [33]. Its principle is based on the roller-on-ring test according to DIN 51347-1.…”

“…The steps of each test run are repeatedly carried out and in each another load step is added until welding takes place which causes seizure of motor. This phase indicates a complete breakdown of grease lm separating the roller element and ring [33]. The test is repeated three times to ensure the obtained results.…”

“…Nanomaterials [32], such as activated carbon nanoparticles [33], boron nitride [34], carbon nanotubes [35,36], graphene and its oxide [37][38][39], are considered as more eco-friendly anti-wear (AW) and extreme pressure (EP) additives to lubricants. Effective AW agents represented in metal oxide nano-additives, such as titanium dioxide [40,41] and ZnO [42][43][44], act as antioxidants in order to stabilize the physical properties of oil under harsh conditions.…”

Investigation of Graphene Platelet-Based Dry Lubricating Film Formation in Tribological Contacts

“…Studies of graphene platelets as a grease additive could prove the outstanding effect as a 2D nanomaterial in reducing friction and wear, as shown by Pape et al [12], as well as by Nassef et al [13][14][15]. Kim et al achieved good lubricating conditions for reduced graphene oxide (rGO) coatings on AISI 440C stainless-steel balls sliding against a silicon specimen under water lubrication conditions [16].…”

Tribological Performance Evaluation of Greases on a Four-Ball Tester with Graphene Oxide Nanoparticles

“…Jiusheng et al prepared novel nanomagnetic grease that exhibited favorable lubricating properties; they also analyzed the interaction between the magnetic grease and the original grease to determine the mechanism by which the magnetic grease provided lubrication. The antiwear and EP properties of the greases were improved massively in some cases. ,,− …”