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This work presents the friction and wear behaviour of two fully formulated (polyalphaolefin- and mineral-based) wind turbine gearbox oils separately additivated with two ionic liquids ([Choline][NTf2] and [BMP][NTf2]) at 5wt% concentration. A tribometer using a ball-on-plate reciprocating configuration is adopted for friction and wear experiments. Friction is measured during tests and the worn surface...
Among the wear quantification techniques applied to point contacts, the most typical one consists of measuring the longitudinal and transversal wear scar diameters of the worn surface. However, this method does not provide information about the distribution of the wear along the worn surfaces. As a result, the wear prediction using wear scar diameters could be misrepresentative because of the irregular...
This work presents and discusses the tribological behavior of NiCrBSi coatings obtained by diode-laser cladding and with good high-temperature antiwear behavior, textured by aNd-YAG laser to achieve good friction behavior. Different densities and distances between dimples were tested by obtaining their coefficients of friction at different sliding speeds under a load of 100N with a CETR UMT-3 tribometer...
Boundary film formation of ionic liquid (IL) 1-hexyl-3-methylimidazolium tetrafluoroborate, [HMIM][BF 4 ], as an additive of hydrocracked mineral oil is evaluated for a steel–steel contact. Accelerated wear testing was carried out using a high frequency reciprocating rig (HFRR) under these test conditions: maximum contact pressure of 1.04GPa, two different temperatures (40 and 100°C) and three...
This work presents and discusses the friction behaviour of a NiCrBSi coating lubricated by CuO nanoparticle suspension (nanolubricant or nanofluid) in a polyalphaolefin (PAO6). CuO nanoparticles were separately dispersed at 0.5 and 2.0wt% in PAO6. Friction reduction properties were obtained using a block-on-ring tribometer, where blocks were coated with a NiCrBSi alloy using the laser cladding technique...
The erosive wear behaviour of AISI H13 tool steel and AISI 4140 steel has been investigated in this work using a sand blast-type rig. Samples of six different hardness levels (from annealed to 595HV) were produced and subsequently tested using silica sand as the erodent material at impact angles ranging from 10° to 90°, air drag pressures of 0.689 and 1.38bar (10 and 20psi respectively), impact speeds...
Oil transporting gas lines are exposed to corrosive–erosive wear mechanisms due to fluid flow conditions in gas transportation processes. Combined parameters like fluid flow regime and chemical composition of the wall deposited products increase oil gas pipes wearing. Corrosion–erosion laboratory tests on API X52 steel grade were performed to study corrosion rate effect of inhibitors added to residual...
In this paper two room-temperature ionic liquids (ILs), 1-hexyl-3-methylimidazolium tetrafluroborate [HMIM][BF 4 ] and 1-hexyl-3-methylimidazolium hexafluorophosphate [HMIM][PF 6 ], have been studied as 1%wt. additives of a mineral hydrocracking oil for steel–steel contacts. Rheological properties of the mixtures and base oil were determined over shear rates and temperatures ranging...
This work presents and discusses the antiwear behaviour of nanoparticle suspensions in a polyalphaolefin (PAO 6). CuO, ZnO and ZrO 2 nanoparticles were separately dispersed at 0.5%, 1.0% and 2.0%wt. in PAO 6 using an ultrasonic probe for 2min. AW properties were obtained using a TE53SLIM tribometer with a block-on-ring configuration. Tests were made under a load of 165N, sliding speed of 2m/s...
This work presents and discusses the extreme-pressure behaviour of nanoparticle suspensions in a polyalphaolefin (PAO 6). CuO, ZnO and ZrO 2 nanoparticles were dispersed at 0.5, 1.0 and 2.0wt.% in PAO 6 using an ultrasonic probe during 2min and EP properties were obtained using a Stanhope Seta Shell Four-Ball EP Lubricant Tester according to ASTM D2783. The ball test material was AISI 52100...
This paper analyses the influence of the processing conditions on the microstructure and wear behaviour of NiCrBSi coatings. Ni-base alloys, which are widely used to obtain wear resistant coatings, are usually heat treated after thermal spraying to improve their tribological properties. Thus, three different processes are studied: flame spraying combined with flame remelting, flame spraying combined...
Corrosive wear failure in gas pipelines can potentially cause substantial human and economic losses. This work presents the failure analysis of an API 5L X52 steel grade section of a pipeline used in an underground transportation, which is located next to a natural gas extraction plant. A T-shape section of this line, failed by perforation under unknown circumstances. Chemical and mechanical characterization...
Sand cores are extensively used on automotives foundries, if a core box is used as core making pattern; erosive wear damage is caused by the silica sand blown. Multiple sand impacts affect the dimensional profile of the core box when the sand is blown causing core rejection. The objective of the present study is to determine the erosion wear rate and the erosive wear mechanism on two tool steel grades,...
Flame spray coatings are widely used in industry because of low cost and process simplicity. However, high porosity and poor adherence to the substrate means that quality is poor, though it can nevertheless be improved by subjecting coatings to a remelting using a technique that usually involves an oxyacetylene flame. The study that follows is an attempt to evaluate a laser technique as an alternative...
The work is based on the dry sliding wear of NiCrBSi coatings deposited on the plates of grey cast iron (DIN GG30) using the laser cladding technique, the parameters of which were such as to provide almost crack-free coatings with minimum dilution and very low porosity. The post-laser treatment microstructure showed up as a dendritic structure matrix which is a solid solution of Ni and chromium-rich...
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