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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...
The properties of machining rate distribution in the machining zone of the hydrodynamic polishing process are experimentally investigated in this study. The patterns of machining rate distributions are compared to that of film thickness distributions between tool and work surface. It is shown that the patterns of machining rate distribution have similar features as that of film thickness one under...
There has been a growing concern for the use of mineral oils because of the worldwide interest in environmental issues. This has promoted the use of ashless additives as environmental friendly lubricants. A potential ashless additive, S-[2-S-(2-hydroxylpropyl)benthiazole]dioctyldithiocarbamic acid ester, was prepared in this work. The friction and wear behaviors of the synthesized compound as an additive...
Solid particle erosion of steam path surfaces is a major concern in steam turbines. This is mainly due to the formation of magnetite on the inside of boiler tubes. This builds up, spalls and travels along with the steam causing erosion in areas where steam velocities are the highest. The steam velocities are the highest in the high pressure sections of steam turbines. The erosion depends upon the...
Solid-particle erosion of Portland cement and Portland-cement-based concrete, and for comparison a nuclear-waste glass, was studied. Using angular Al 2 O 3 erodents of mean diameter~42, 63, 143, and 390 μm impacting at 20 and 90 o to the surface at 50 m/s, we found the erosion rate to be a strong function of erodent size. Erosion rates of the three targets by rounded SiO ...
The origins of friction and wear of the thin metallic layer of metal evaporated (ME) magnetic tapes were determined at an asperity level using a modified commercial video cassette recorder (VCR) as a tape transport, magnetometer and tribometer. The VCR was instrumented to measure friction force between the rotary heads and tape, head-to-tape spacing to nanometer vertical resolution, and sub-microsecond...
The boundary lubricating film in a low velocity metalworking process has been studied using atomic force microscopy (AFM) and scanning laser microscopy (SLM). It is postulated that the workpiece surface irregularities reflect the lubricant film thickness even in boundary lubrication. A new sheet compression test was developed. This test uses a block gauge as a flattening tool and is conducted under...
The effect of abrasive particle size on the wear rate is well known. For small particles the wear rate increases with increasing particle size. Above some critical size the wear rate becomes almost independent of further size increases. Several theories have been presented to explain the size effect. We have examined a theory based on the particle shape, specifically the bluntness of the abrading...
Rolling contact stress and failure analyses were conducted for the Hadfield steel (manganese steel) and the Bainitic alloy (J7). The first alloy is used in diamond crossings and frogs in the railroad industry while the second alloy is a candidate for such applications. A series of fatigue experiments were conducted on these alloys to establish the damage parameters. The proposed fatigue damage parameter...
Friction and wear tests were carried out with an Si 3 N 4 pin and five kinds of ceramic disks at elevated temperatures (25 o C~600 o C) in vacuum (5.8x10 -3 Pa) under a normal load of 6.02 N and a sliding speed of 0.2 m/s. For each test, the extent of damages on sliding worn surfaces, the wear rate and the friction coefficient were measured. Moreover, analysing...
In this paper, an organic compound containing S, N, B and O elements is synthesized with the reaction of 2-mercaptobenzothiazole and chloroethanol in aqueous solution firstly, then the product reacts with butanol and boric acid in toluene solution at reflex for 6 h. Its friction and wear properties as additives in liquid paraffin were evaluated using four-ball machine and antiwear mechanisms were...
Sputter-coatings of carbon with 10% nitrogen incorporation grown to four different thicknesses of 10, 50, 100 and 200 nm were prepared by ion beam assisted depositing (IBAD) onto Si(111) substrates and then both surface characterized by an atomic force microscope (AFM) and nano-indented by a Thin Film Hardness Analyser. In sliding against a diamond pin at a relative humidity of 40%, CN 0....
Friction at the tooling-workpiece interface is very important in sheet metal forming operations. Accurate knowledge of friction at such interfaces is needed for process design and analysis, numerical process simulation and validation and control of forming processes. Two physical models or friction simulators, based on the stretching of a strip around a pin, were developed to characterize sheet metal...
Wheat starch blast cleaning is used increasingly to remove organic coatings from aircraft. The process was investigated to clarify aspects of the mechanism by which a urethane topcoat and an epoxy primer are removed from aluminum and three epoxy composites (carbon, glass, and aramid fiber). Experiments included an examination of the impact sites created by individual wheat starch particles, the measurement...
An experimental technique based on elastic stress wave propagation phenomena in a slender rod is utilized for determining the dynamic Vickers indentation hardness in metals. Dynamic Vickers hardness (DVH) for several engineering metals is found to be greater than their static Vickers hardness (VH). The results were verified by obtaining the constitutive response of materials at similar strain rates...
The objective of this study is to interpret experimentally observed surface cracking and pitting caused by cyclic sliding contact. In our model, the fracture of two surface-breaking cracks in a homogeneous half plane is analyzed using the finite element technique. The half plane is loaded by a sliding rigid cylinder, which models a moving asperity. Stress intensity factors for the two crack tips are...
A wear model considering surface topography is developed and used to calculate wear in conical spinning contacts both analytically and with FEM, using the commercial software ANSYS 5.0A. The model is based on the linear wear law and the Abbott curve linearisation. In finite element analysis (FEA) wear simulations, the wear law is discretised and Euler integration scheme is used. In the analytical...
The present paper is a report of an investigation made to study the unlubricated sliding wear behaviour of zinc-aluminium (ZA) alloy composites reinforced with zircon particles of size 30-50 μm. The content of zircon in the alloy was varied from 1-5% in steps of 2 wt.%. The liquid metallurgy technique was used to fabricate the composites. A pin-on-disc wear testing machine was used to evaluate the...
High velocity oxy fuel (HVOF) cermet coatings have been used to reduce the damage caused by solid particle erosion (SPE). The current work investigated the erosion resistance of FeCrAlY-Cr 3 C 2 and NiCr-Cr 3 C 2 cermet coatings with carbide levels ranging from 0-100% (in the pre-sprayed powder) in order to determine the optimum ceramic content for the best erosion...
Diamond coatings were deposited on commercial, cemented tungsten carbide tools of various cobalt content (3%, 6% and 12% Co) by low-pressure microwave CVD to assess the role of cobalt on the quality and adhesion (reliability) of diamond coatings. The samples were characterized by micro-Raman spectroscopy, scanning electron microscopy, and low angle X-ray diffraction. Problems associated with the detrimental...
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