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Machinery wear is a major cost to industry and its minimisation would result in significant savings. In order to do this, it is important to understand the mechanisms of wear. Techniques have to be developed to enable the detailed measurement and analysis of wear surfaces. Conventional methods of surface measurement have involved profilometers. Profilometers, however, have severe limitations in terms...
A new manufacturing process and a new family of composite materials (bronze matrix + friction modifiers) for lubricated tribological systems, such as synchronizer rings in manual gear boxes, has been developed. The research has provided a better understanding of lubricating oil film formation and how to stabilize it by a suitable surface chemistry and morphology, as well as the ability to produce...
Abrasive wear tests of low Cr steel and carbon steel under the effect of impact-abrasion were carried out. The topography and the composition of specimen surface were analyzed using scanning Auger microprobe (SAM) and X-ray photoelectron spectroscopy (XPS). It was observed that wear loss was dependent on chemical environment, curvature radius of the specimen surface and thermal processing history...
Laser processing is a promising technique for alloying and synthesis of wear resistant layers. In this work, commercially pure titanium was laser alloyed with various proportions of nitrogen and carbon monoxide in order to produce a composite surface layer. The following gas mixtures were selected: 100% N 2 , 67% N 2 + 33% CO, 50% N 2 + 50% CO, 33% N 2 + 67% CO and...
The tribological properties of four different materials are investigated, tetragonal zirconia (Y-TZP), Al 2 O 3 , dispersed in Y-TZP (ADZ), ZrO 2 dispersed in Al 2 O 3 (ZTA) and Al 2 O 3 (with 300 ppm MgO). These materials are used as a cylinder sliding against a plate of Y-TZP (TZ-3Y)). Compared to Y-TZP, the wear resistance of ADZ composites...
This paper reports the evaluation of extreme-pressure activity of lubricants containing alkyl para substituted benzyl sulfides. These additives exhibited good activity by increasing seizure and welding load compared to the base fluid. A polyethoxylated chain in para position on additives has been found to enhance the load-carrying capacities of the emulsion. Electron probe microanalysis was conducted...
S-[2-(2-hydroxygenacetyl)thiobenzothiazol-1-yl]pentanyl xanthates was synthesized as potential lubricating oil additive. The friction and wear behaviors of the synthesized compound as an additive in liquid paraffin were evaluated with a four-ball machine. The tribochemical reaction of the additive with a metal surface was investigated by X-ray photoelectron spectroscopy. It was found that the novel...
In automotive brake systems, high temperatures and pressures are generated at the contacting surfaces. This affects the pad and disc materials, creating a friction film between the surfaces, which consists of wear particles and volatile reactants from the pad and disc. To acquire suitable tribological properties, a pad matrix contains up to 20 different ingredients, mainly selected from experience...
Two new derivatives of dioctyldithiocarbamate, one containing heterocyclic group (benzimidazole) and another being an aliphatic compound, were synthesized and characterized. Their tribological performances as lubricant additives in liquid paraffin were evaluated by four-ball and SRV friction and wear testers. The results showed that S-benzimidazole substituted dioctyldithiocarbamate (BMZ-C 8 ...
The authors present a new method for research of scuffing. It is realized on the four-ball tester and considers scuffing as a process leading to seizure, i.e. the stopping of the relative movement of a tribosystem. During a run, load increases continuously.Using the method, tribological experiments were performed employing various lubricants; viscosity improvers, AW and EP additives were added to...
The paper considers some ways to improve surface engineered coatings for cutting tools. These coatings were formed by two stages: diffusion saturation with nitrogen (ion nitriding) and application of the (Ti, Cr)N hard coating by means of the cathode arc plasma deposition process (CAPDP). The coating includes also an additional ion alloyed layer applied to the previously nitrided surface of HSS. Such...
The influence of tribological conditions on the surface reactions occurring between zinc dialkyldithiophosphate (ZnDTP) and steel surfaces has been studied by means of a combination of X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS), in situ attenuated total reflection (ATR) infrared spectroscopy, and high-throughput combinatorial approaches. Purely...
The effect of particle velocity and mean impact angle on the corrosion–erosion of solubilized AISI 304 and quenched and tempered AISI 420 stainless steels was studied. The tests were performed using slurry composed of 0.5M H 2 SO 4 +3.5% NaCl and 30wt% quartz particles with 0.21–0.30mm mean diameter. Potentiodynamic curves, AFM and SEM analyses allowed identification of the wear mechanisms...
Tribochemical properties are an essential component of the efficiency of metal forming lubricants. Their understanding, a basis for the selection of adequate additives, heavily relies on surface analytical techniques. In the last ten years, we have applied time-of-flight secondary ion mass spectroscopy (ToF-SIMS) to the analysis of the reactions of strip surfaces with typical additives of cold strip...
This study examines the feasibility of using electron back scattered diffraction (EBSD) as a way of examining the plastic deformation near to wear damage on the surface of a WC/Co hardmetal. Samples were scratched in micro-scratch tests to simulate the type of contact that would occur in abrasion. It was found that EBSD gave clear information that could be correlated with the degree of plastic deformation...
Metal fiber brushes are of interest in many high current density applications due to their high conductivity and low wear rates in humid environments. The frictional properties and wear behavior of a copper fiber brush sliding against a copper counterface in humid environments under high current densities (180A/cm 2 ) were investigated at low sliding velocities (10mm/s). A linear reciprocating...
This work presents an investigation of the tribocorrosion of ruthenium in sulphuric acid solutions.The study was focused on the effect of the electrode potential on wear of ruthenium during sliding against an inert alumina ball in a reciprocating sliding tribometer fitted with an electrochemical cell. Surface chemical and electrochemical properties were characterized using AES, XPS, SEM and electrochemical...
In this paper, 316L stainless steel micro-mixers were fabricated by micro powder injection molding. The tribological behavior of the stainless steel micro-mixer sliding against AISI 52100 steel at low loads was investigated using a ball-on-disk tribometer. The morphologies and compositions of the worn surfaces were analyzed by SEM, Raman and XPS. The results showed that the wear mechanism of stainless...
Friction heat induced by high sliding speed affects tribologial properties. Tribological behaviours of chromium steels were investigated using a pin-on-disc tribometer in various atmospheres (O 2 , N 2 and CO 2 ). The tests had performed at sliding speeds from 30 to 60m/s and a contact pressure of 1.33MPa. The results show that the wear rate of the steel pin is the lowest in...
It is a well-known fact that materials that consist of both brittle and ductile constituents can show erosion behavior in either a ductile or a brittle manner. The high-velocity oxy-fuel (HVOF) sprayed WC-Co/NiCrFeSiB coatings on GrA1 boiler tube steel exhibit composite ductile and brittle modes of erosion under angular silica sand erodent of size 125–180μm impacted at 40m/s. The HVOF spraying leads...
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