Overbased Calcium Sulfonate Research Articles

Investigating the effect of overbased sulfonates on calcium sulfonate complex grease: enhancements in physicochemical, rheological, and tribological properties.

Overbased sulfonate plays a crucial role in calcium sulfonate complex grease, significantly impacting the grease's performance characteristics. Herein, the calcium sulfonate complex grease was formulated using overbased calcium sulfonate (T106D) and overbased magnesium sulfonate (T107) in ratios of 1 : 2, 1 : 1, and 2 : 1, labeled as CMSCG (1 : 2), CMSCG (1 : 1), and CMSCG (2 : 1), respectively. This study examined the effects of overbased sulfonates on the physicochemical, anti-corrosion, rheological, and tribological properties of the grease. Results showed that CMSCG (1 : 2) exhibited superior physicochemical properties, with the highest dropping point (354 °C), the lowest penetration (161 (0.1 mm)), and the least oil separation (1.25%). Exposure to a salt spray environment significantly altered the grease's rheological properties. The combination of T106D and T107 enhanced the corrosion resistance of the grease, attributed to the formation of a corrosion inhibition layer. Incorporating T107 increased both the yield stress and hysteresis area of the calcium sulfonate complex grease. The CMSCG (1 : 2), CMSCG (1 : 1), and MSCG showed the high thixotropic ring area, indicating the poor thixotropy. The calcium sulfonate complex grease formulated with T107 showed the highest yield stress (558 Pa). The friction mechanism revealed that MSCG showed the optimal friction reduction properties, and CMSCG (1 : 1) demonstrated the optimal wear resistance, which are attributed to the synergistic effects of tribo-chemical films composed of CaO, CaCO3, FeSO4, MgCO3, and iron oxide.

Tribological Investigation of the Effect of Nanosized Transition Metal Oxides on a Base Oil Containing Overbased Calcium Sulfonate

In this study, copper(II) oxide, titanium dioxide and yttrium(III) oxide nanoparticles were added to Group III-type base oil formulated with overbased calcium sulfonate. The nanosized oxides were treated with ethyl oleate surface modification. The tribological properties of the homogenized oil samples were tested on a linear oscillating tribometer. Friction was continuously monitored during the tribological tests. A surface analysis was performed on the worn samples: the amount of wear was determined using a digital optical and confocal microscope. The type of wear was examined with a scanning electron microscope, while the additives adhered to the surface were examined with energy-dispersive X-ray spectroscopy. From the results of the measurements, it can be concluded that the surface-modified nanoparticles worked well with the overbased calcium sulfonate and significantly reduced both wear and friction. In the present tribology system, the optimal concentration of all three oxide ceramic nanoadditives is 0.4 wt%. By using oxide nanoparticles, friction can be reduced by up to 15% and the wear volume by up to 77%. Overbased calcium sulfonate and oxide ceramic nanoparticles together form a lower friction anti-wear boundary layer on the worn surfaces. The results of the tests represent another step toward the applicability of these nanoparticles in commercial engine lubricants. It is advisable to further investigate the possibility of formulating nanoparticles into the oil.

Influence of additive-derived reaction layers on white etching crack failure of SAE 52100 bearing steel under rolling contact loading

It is a common observation that rolling bearings fail due to the formation of white etching areas and white etching cracks (WEA/WEC). Branching crack networks beneath the surface and an altered microstructure known as WEA are characteristics of the failure mode. Therefore, the WEA-related cracks are known as WEC. In order to shed more light on this so far not fully understood phenomenon, the present study focussed on the role of specific oil additives and their influence on the formation of reaction layers and how these possibly affect the WEA/WEC formation. For this purpose, comprehensive tests were conducted on a three-ring-on-roller test rig using two different fully formulated oil lubricants with samples of SAE 52100 bearing steel. A subsequent carried out analysis by wavelength dispersive X-ray spectroscopy (WDX) and transmission electron microscopy (TEM) revealed the differences in the formed additive-derived reaction layers. While a known WEA/WEC-critical oil formulation, containing the two additives zinc dithiophosphate (ZDDP) and overbased calcium sulfonate (OBCaSul), did not result in any significant formation of reaction layers during mixed / boundary lubrication at an oil influx temperature of 95 °C, an oil formulation containing barium and phosphorus performed excellent in this respect. This finding is related to the observation that provocation of WEA/WEC failures in our experiment was always unsuccessful when the barium- and phosphorus-containing oil was used. The use of barium phosphate containing lubricants could therefore be an effective measure to prevent or significantly delay WEA/WEC damage to bearings.

The effect of over-based calcium sulfonate detergent additives on white etching crack (WEC) formation in rolling contact fatigue tested 100Cr6 steel

Abstract Over-based calcium sulfonate (OBCaSul) additives in oils are considered potentially critical in driving WEC formations, this ‘driving’ effect being unclear. Rolling contact fatigue testing of 100Cr6 steel using FE8 and PCS Micro-Pitting-Rig lubricated with oils containing varying OBCaSul concentrations have been conducted, tested samples being analysed using serial sectioning, Thermal desorption analysis (TDA) to measure hydrogen diffusion, and SEM/EDX of the tribofilms formed. Results show that OBCaSul concentration appears to affect WEC formation propensity, a reversal relationship of formations being shown between test rigs. Evidence shows oils containing OBCaSul form thick Ca dominated tribofilms, potentially promoting hydrogen diffusion and WEC formations in the FE8 rollers, where thinner Zn S tribofilms on the FE8 raceways may demote hydrogen diffusion and WEC formations.

Evaluation of anti-galling property of sulfurized olefins with overbased calcium sulfonates on stainless steel by cup internal ironing test

Abstract The authors prepared sulfurized olefin and overbased calcium sulfonate with well-defined molecular structures and examined their performance by way of a cup internal ironing test, which can simulate the conditions of cold ironing. When sulfurized olefins were combined with overbased calcium sulfonate, anti-galling performance was better than that of sulfurized olefins alone. It was found that, there was blending ratio of sulfurized olefin and overbased calcium sulfonate that was optimal for anti-galling performance. The formation of a lubrication film was promoted because the sulfurized olefin and the overbased calcium sulfonate played complementary roles. Further, the promotion of formation of a mixed film of sulfur and calcium lead to improved anti-galling performance.

Studies of the Influence of Temperature and the Energy State of the Surface Layer of Adsorbents on Wall Effects in Soap-Based Greases

This paper presents the results of studies of wall effects in commercial soap-based greases LT4-S2 and HUTPLEX EP-2, thickened with, respectively, lithium 12-hydroxystearate and overbased calcium sulfonate. The studies were conducted in the presence of five different materials: copper alloy C11000, bronze B476, EPDM rubber and PTFE and PU thermoplastics. The influence of the energy state of the surface layer of the adsorbents and temperature (ranging from −20 to 60 °C) on the intensity of wall effects was investigated. Changes in the structural viscosity and shear stress in the boundary layer area in the greases and the soap-based thickener’s ability to adsorb on the surfaces of the adsorbents were determined by evaluating the rheological parameter plateau modulus.

Combined Effect of Phosphate Ester and OBCS on Tribochemical Decomposition of Hydrocarbon Oil on Nascent Steel Surfaces

Combined effect of additives, over-based calcium sulfonate (OBCS) and phosphate ester were investigated on the decomposition of multi-alkylated cyclopentane (MAC). The decomposition processes of the lubricants on the nascent surface of bearing steel AISI52100 were investigated using a ball-on-disk friction tester in a vacuum chamber with a quadrupole mass spectrometer. According to our previous report, the decomposition reaction can be deactivated by the effect of lubricant additives such as organic sulfides and organic phosphates. In this report, the order of efficiency in decreasing the decomposition rate was: OBCS < phosphate ester < phosphate ester + OBCS. The mixed additive was more effective and stable for suppression of the tribochemical decomposition under severe contact conditions of high load and high sliding speed. The critical load for the decomposition which is the lowest load to detect the gas evolution due to the decomposition increased with the mixed additive. XPS and TOF–SIMS analysis revealed that additive molecules competitively chemisorbed on the steel surface and reaction occurred by the formation of calcium phosphate, which covered the steel surface and deactivated the catalytic activity of active sites leading to deactivation. As a result, decomposition of MAC decreased significantly by the combined effect of the additives.

Study of Conductive and Friction Properties of Grease Containing Carbon Black Additive

The conductive and fiction properties of overbased calcium sulfonate complex grease and lithium grease containing carbon black (CB) additive were investigated in detail. The results indicate that CB can dramatically improve the conductivities of the greases. Also the tribol-test results indicate that the CB can dramatically improve the tribological properties of the greases. The lithium greases containing CB, have better tribological properties than overbased calcium sulfonate complex greases. Among the lithium greases, 5% CB contained grease performs the best friction reduction properties, and among the overbased calcium sulfonate complex greases, 6% CB contained grease performs the best friction reduction properties.

Universal Phase Transformation Mechanism and Substituted Alkyl Length and Number Effect for the Preparation of Overbased Detergents Based on Calcium Alkylbenzene Sulfonates

Overbased calcium sulfonate is one of the largest commercially produced nanomaterials; the phase transformation mechanism involved in the key process of carbonation reaction for overbased detergent preparation has not yet been fully understood. Following our previous investigation based on the heavy alkylbenzene sulfonate (HABS) surfactant of industrial byproduct, two commercial products with well-defined chemical compositions and structures, long-chain alkylbenzene sulfonate (LCABS) and comparative short-chain linear alkylbenzene sulfonate (SLABS), are employed in this study as model surfactants for further mechanism study of this pivotal process by the combination of analytical techniques such as potentiometric titration, DLS, TEM, FTIR, and XRD. It has been demonstrated that amorphous calcium carbonate (ACC) is a prerequisite for the preserving and stabilization of the alkaline reserve, especially under thermal work environment. The phase transformation from ACC to crystalline vaterite polymorph rather...

Comparison Friction and Wear Properties of Overbased Calcium Sulfonate Complex Grease and Polyurea Grease

The friction and wear properties of the overbased calcium sulfonate complex grease and polyurea grease were evaluated using an Optimol SRV reciprocating friction and wear tester under the boundary lubrication conditions. The morphologies of the worn surfaces of the AISI 52100 steel discs were observed using a scanning electron microscope (SEM). In addition, the elemental compositions and chemical states of several typical elements on the worn surfaces of the AISI 52100 steel discs were examined by means of X-ray photoelectron spectroscopy (XPS). The results show that the overbased calcium sulfonate complex greases and polyurea grease have stable friction coefficients as low as 0.10-0.11. The calcium sulfonate complex grease has better wear resistance properties than polyurea grease, polyurea grease has better reducing friction properties than calcium sulfonate complex grease, According to the XPS analyses, it is considered that the formation of tribochemical films led to lower friction coefficient and high wear resistance.

Tribological Properties of the Overbased Calcium Sulfonate Complex Greases Containing Different Lubricant Additives

Overbased calcium sulfonate complex greases have excellent friction and wear properties and have been widely used in metallurgy and mining equipment. The effects and tribological performance of molybdenum dialkydithiocarbamate (MoDTC) and ionic liquid 1-(2-hydroxyethyl)-3-methylimidazolium bis (trifluoromethylsulfonyl) imide ([C2OHMim][NTf2]), 1-(2-hydroxyethyl)-3-hexylimidazolium bis (trifluoromethylsulfonyl) imide ([C2OHHim][NTf2s]), added in overbased calcium sulfonate complex grease as additives were investigated by using reciprocating ball-on-disk sliding friction tester. The results showed that the two kinds of additives with a certain range of concentration could improve the tribological properties of greases.

Study of Friction and Wear Behavior of Overbased Calcium Sulfonate Complex Grease Containing Anti-Oxidant Additives

The fiction and wear properties of overbased calcium sulfonate complex grease containing anti-oxidant additives were investigated using MFT-R 4000 reciprocating friction and wear tester.The results show that the overbased calcium sulfonate complex greasecontaining 2%dialkylated diphenylamine (L57) having better friction-reducing properties than the grease containing 2,6-di-tert-butyl-phenol (L135) and the grease containing 5% L57.

Synergistic Effects of MoDTC and Overbased Calcium Sulfonate Additive

The synergetic effects of molybdenum dialkyldithiocarbamate (MoDTC) and overbased liner alkyl benzene synthetic calcium sulfonate (OBCaS) on the tribological performance of lubricant were investigated using reciprocating ball-on-disk sliding friction tester. The results showed that the two kinds of additives with a certain range of concent ration could improve tribological properties of alone MoDTC. The mass percent of 0.5% MoDTC and 2% OBCaS in pure poly-alpha-olefin (PAO) has the best friction reducing and anti-wear properties.

Tribological Behavior of Amorphous and Crystalline Overbased Calcium Sulfonate as Additives in Lithium Complex Grease

The aim of this study was to examine the tribological behavior of amorphous overbased calcium sulfonate (AOBCS) and crystalline overbased calcium sulfonate (COBCS, transformed from the AOBCS) as additives in lithium complex grease. The transformation product of the calcium carbonate polymorph from AOBCS was calcite, as determined by Fourier transform infrared spectroscopy. Tribological properties were evaluated by an oscillating reciprocating friction and wear tester and a four-ball tester. The results showed that the addition of COBCS can dramatically improve both the antiwear performance and the friction-reducing and load-carrying properties of the base grease. However, improvement of the tribological properties of the base grease by AOBCS was highly dependent on the concentrations added and the loads applied. The tribological properties of the base grease were improved more by the addition of COBCS than by the addition of AOBCS. X-ray photoelectron energy spectrometry and thermogravimetric analysis revealed that both AOBCS and COBCS underwent complicated tribochemical reactions in the base grease and that chemically reactive films consisting of CaCO3, CaO, iron oxide and organic compounds were formed on the worn surfaces. Taken together with the results of the tribo-tests, we suggest that transformation of the calcium carbonate polymorphs was the main factor in improving the tribological properties of lithium complex grease. The transformation of calcium carbonate polymorphs can broaden the application of AOBCS as an extreme pressure/antiwear additive in greases under boundary lubrication conditions.

Tribological Properties of the Overbased Calcium Sulfonate Complex Greases

The commercial greases for bearing applications should meet the requirements of the severe conditions of use (high load, low friction and low noise etc.). A kind of overbased calcium sulfonate complex greases was evaluated using an UMT-II friction tester, the commercial lithium greases as reference. The morphologies of the worn surfaces were observed using a scanning electron microscope (SEM). The results show that the overbased calcium sulfonate complex greases have stable friction coefficients as low as 0.090-0.094. At the same time, the overbased calcium sulfonate complex greases exhibited higher wear resistance than that of commercial lithium greases.

Boundary film formation from overbased calcium sulfonate additives during running-in process of steel–DLC contact

The initial stage of boundary film formation from overbased calcium sulfonate at steel–DLC (diamond like carbon) contact was studied. A running-in process was clearly observed by the combination of fresh DLC with fresh steel or fresh DLC with rubbed steel. On the other hand, rubbed DLC does not possess the running-in process. Surface analysis by TOF-SIMS was applied to investigate the formation process and structure of films. It was found that the transfer of iron from the steel ball on to the DLC surface plays a significant role in the formation of boundary film. The depth profile of the film was also obtained by means of an etching technique. The boundary film on steel ball and DLC are mainly composed of iron and calcium oxide. However the depth profiles indicate that distribution of calcium oxide on steel ball is different from that on DLC coated disk.

Study of Surface Films of the ZDDP and the MoDTC with Crystalline and Amorphous Overbased Calcium Sulfonates by XPS

The role of amorphous or crystalline overbased detergent and sulfur containing AW/EP additives on the surface films created in a tribometer was investigated. In the crystalline overbased sulfonate containing samples the weld point was higher than for the equivalent blend using an amorphous overbased sulfonate. The calcium carbonate core of the overbased sulfonates was deduced to be present in the surface film when combined with either ZDDP or MoDTC. For samples containing ZDDP the crystalline overbased sulfonate, reduced the phosphate film thickness, while for the MoDTC it reduced the MoS2 film thickness. In both cases significantly more carbon, likely as calcium carbonate (which acts to improve the EP/AW properties of the lubricant), was present when using the crystalline overbased calcium sulfonate compared to the amorphous overbased calcium sulfonate.

Determination of Synthesis Conditions of Medium, High, and Overbased Alkali Calcium Sulfonate

This review covers a method for preparing an overbased detergent−dispersion additive called overbased calcium sulfonate solution (OBCSS) containing 38.9% (w/w) CaCO3, with a total base number (TBN) value of 436 mg KOH, starting from neutral calcium sulfonate solution (NCSS).1,2 After the column conditions were optimized, the reaction parameters (PCO2 and the amounts of Ca(OH)2, water, and monoethanolamine (MEA)) were examined throughout the tests. The first product medium alkali calcium sulfonate solution (MACSS) with 8.5% (w/w) CaCO3 (TBN = 95 mg KOH/g) is obtained, but higher base values could not be reached. In the second stage, monoethanolamine is added to the feed as a promoter and high alkali calcium sulfonate solution (HACSS) containing 30.4% (w/w) CaCO3 with the value of TBN = 274 mg KOH/g is obtained. In the third stage of the study, targeted product OBCSS is obtained by using HACSS as a feedstock component instead of NCSS.

Study of surface films of crystalline and amorphous overbased sulfonates and sulfurized olefins by X-ray absorption near edge structure (XANES) spectroscopy

In the past large synergistic effects have been reported for combinations of overbased sulfonate and sulfurized olefin in four-ball EP testing. In this study, we examined the effect of crystallinity on the formation of the tribofilms using X-ray absorption near edge structure (XANES) spectroscopy. Using this technique, we were able to differentiate the carbonate from organic carbon in C K-edge spectra, as well as, determining the difference between FeS, FeS2, RSO3−, and SO42− in the sulfur spectra. While the overbased calcium sulfonates do not react strongly with the substrate there is evidence to suggest that the overbased sulfonate promotes decomposition of the sulfurized olefin on the surface to form both CaSO4 and FeS, which improves the EP performance of the lubricant. A putative intermediate is H2S from the decomposition of the sulfurized olefin which can react with O2 and the Fe-rich surface to form FeSO4 and FeS, respectively. A new ‘FeS’ species has been detected in the tribofilms that is believed to be a non-stoichiometric Fe-enriched FeS. Depending on the presence or absence of the overbased calcium sulfonate either FeSO4 or FeS formation is favored and changing the concentration of the crystalline, C300C, or amorphous, C400A, overbased calcium sulfonate from 5% to 10% does not appear to have any effects on FeS formation, although the C300C produces more Fe-enriched FeS than the C400A in the bulk.

臭気対策を施した高性能温間鍛造油の開発

Recently the demands of a performance and environmental treatment for forging lubricant oil have been getting stronger. Especially, in the warm forging which is spread gradually for the purpose of near net shaping or complex shaping, the environmental problem is considerable. Concerning to the lubricant performances of the oil, both of the high lubrication and cooling abilities are required in warm forging. As for the environmental treatment, the harmful gas and sharp smell must be reduced as much as possible. We have developed the new oil contained overbased calcium sulfonate for warm forging to be satisfied with the needs. The results are follows. 1. The smell was much reduced even at 800 ℃ comparison to conventional high performance forging oil which contains Zn-DTP. 2. The forging load decreased about 35 % at 800 ℃ in backward extrusion. 3. The depth of punch wear was reduced about 14 % after 5000 shots.