Research Progress of Nano Copper Lubricant Additives on Engineering Tribology

Nanoparticles have as characteristics super sliding, extreme pressure, self-healing, etc., which can improve the friction reduction and anti-wear performance of sliding components, when used as lubricating oil additives. Nano-copper particles have a good synergistic effect with other antifriction agents, anti-wear agents, antioxidants and grease additives because of their low shear strength and grain boundary slip effect, showing a better anti-friction and anti-wear effect. However, nanoparticles are prone to conglomerate, and this causes a bottleneck in the application of dispersant for nano-copper in a lubricating oil system. The regulation of nanosized effect and surface properties has great engineering significance in compensating for the precision in manufacturing accuracy. This paper comprehensively reviews the tribological research progress of nano-copper as a lubricant additive, which provides a reference to the application of nano-copper particles as lubricating oil additives on engineering tribology.

Synergistic lubricating performance of h-BN/GF nanoparticles as oil additives for steel-steel contact

The major objective of this work is to investigate the synergistic lubricating performance of hexagonal boron nitride (h-BN) and graphite fluoride (GF) nanoparticles (NPs) as lubricant additive in white oil. The tribological tests were carried out on steel-steel contacts using reciprocating ball-on-disk tribometer. Compared with white oil, addition of 0.1 wt. % h-BN/GF reduced the friction coefficient, wear rate and wear depth by 41.1 %, 89.1 %, and 92.3 %, respectively. Furthermore, when the mass ratio of h-BN and GF is 1:1 and the content of h-BN/GF nanocomposites is 0.1 wt. % the white oil show the best lubrication and wear resistance performance. Finally, the synergistic lubrication mechanism was investigated, the unique microstructure of the h-BN/GF composite and weak interfacial interaction between h-BN and GF contributed to the formation of continuous and adhesive tribo-films at the interface.

The rheological behavior of crude oil in the presence of palm oil additives

Wax precipitation has become a serious problem for the petroleum industry. The problem occurs when there is equilibrium disturbance on the pressure and temperature as well as crude oil composition. Wax deposits will eventually result in restriction of the fluid flow inside the pipeline, and severe deposition will cause blockage. The chemical additives currently being implemented in the industry have various limitations including the high cost and the irreversible impact it has on the environment. Therefore, the use of cheaper organic wax inhibitor obtained from crude palm oil (CPO) and crude palm kernel oil (CPKO) on the rheology and deposition of wax was investigated by using Chenor waxy crude oil from the Penyu basin, Pahang, Malaysia. To compare the efficiency of palm oil additives in inhibiting wax deposition, currently utilized chemical additives such as triethanolamine (TEA) and ethylene vinyl acetate (EVA) were also examined. The pour point of the crude oil was determined using SETA cloud & cryostat, while the rheological behavior of the crude was determined using a rotational Fann viscometer. The results obtained from this study reveal that CPO and CPKO could be used to improve the flow of crude oil, especially when 1 wt.% CPO or when 0.5 wt. % CPKO is used. It was also noted that the palm-based additives were much more effective at reducing the viscosity of the Chenor crude oil than the commercial wax inhibitor tested (TEA and EVA).

Influence of Base Oil Polarity on the Tribological Performance of Surface Active Engine Oil Additives

Friction, wear and tribofilm growth of organic friction modifiers (glycerol monooleate and oleamide), anti-wear additive (ZDDP) and binary additive system comprising the organic friction modifiers and ZDDP were studied in polyalphaolefin (PAO) and ester oil. The mechanisms underlying base oil polarity-dependent frictional performance of the OFM and AW additives at high temperature (140 oC), either singly or in combination, was investigated in the light of chemical composition analysis of the tribofilms post friction measurements using energy-dispersive X-ray spectroscopy (EDX), static and dynamic time-of-flight secondary ion mass spectrometry (ToF-SIMS). Depending on the rubbing conditions, the boundary friction coefficient of the binary additive systems were found to be either lower than that of individual additives or to lay between the values for the individual additives. Chemical composition analysis of the tribofilms indicated that the nature of base oil controlled interactions between ZDDP and OFM and consequently adsorption and reactive tribofilm formation in the boundary lubrication layer. Surface roughness and wear scar width measured post tribological tests using 3D surface profiler showed improved wear performance in both PAO and ester-based additive formulations.

The Influence of Packing Methods and Storage Time of Poultry Sausages with Liquid and Microencapsulated Fish Oil Additives on Their Physicochemical, Microbial and Sensory Properties

The aim of the study was to evaluate the influence of refined fish oil additives in liquid and microencapsulated forms, packing method (VP—vacuum packing, MAP—modified atmosphere packing) and storage time (1, 7, 14, 21 days) on selected physicochemical, microbiological and sensory characteristics of minced poultry sausage. Principle component analysis (PCA) showed that the fish oil additive, packing method and storage time significantly influenced some of the physicochemical characteristics of the sausages. The pH value was negatively correlated with the type of sample and packing method. The water activity decreased along with the storage time. The sausages with microcapsules had distinguishable hardness, gumminess and chewiness than the other samples. This tendency increased in the subsequent storage periods. The packing method and storage time of the samples had a statistically significant influence on the growth of the total colony count and count of lactic acid bacteria (p < 0.05). The most aerobic bacteria were found in the control sample, and the least in the sample with microcapsules, regardless of the packing method. The use of MAP and the addition of microcapsules resulted in the lowest microbiological contamination of the sausages. The sensory analysis made by a trained panel did not show any significant differences between the samples. After 21-day storage of the sausages there was a slight decrease in some of the sensory parameters, e.g., color, smell, taste. The liquid oil and microencapsulated oil additives in the meat filling did not negatively affect the taste or any physicochemical characteristics of the meat products. From the microbiological perspective, there were better effects from the MAP method.