scholarly journals Self-lubrication of tribologically-induced oxidation during dry reciprocating sliding of aged Ti-Ni51.5 at% alloy

Friction ◽  
2020 ◽  
Author(s):  
Rui Yang ◽  
Wei Ma ◽  
Chunjian Duan ◽  
Song Li ◽  
Tingmei Wang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Friction Pair ◽  
Aged Alloy ◽  
Material Transfer ◽  
X Ray ◽  
Reciprocating Sliding ◽  
Mild Wear ◽  
The Coefficient Of Friction ◽  
High Level ◽  
Wear Transition

Abstract The tribological behaviors of Ti-Ni51.5 at% alloy strengthened by finely dispersed Ni4Ti3 particles in reciprocating sliding against GCr15, Al2O3, and ZrO2 at room temperature were studied. Interestingly, the coefficient of friction (COF) suffered a sheer drop (from 0.9 to 0.2) when the aged alloy slid against GCr15 at a frequency of 20 Hz under a 20 N load without lubrication. However, severe-mild wear transition disappeared when a solutionized alloy was used. Moreover, the COF stabilized at a relatively high level when Al2O3 and ZrO2 were used as counterparts, although their wear mechanisms showed signs of oxidation. Scanning electron microscopy (SEM) and X-ray element mappings of the wear scars of the counterparts clearly indicate that the formation of well-distributed tribo-layer and material transfer between the ball and disk are pivotal to the severe-to-mild wear transition in the aged Ti-Ni51.5 at% alloy/GCr15 friction pair. The higher microhardness and superelasticity of the aged alloy significantly accelerate the material transfer from GCr15 to the disk, forming a glazed protective tribo-layer containing Fe-rich oxides.

Electrodeposition of Zinc from Binary ZnCl2-DMSO2 Molten Electrolyte at Room Temperature

2007 ◽  
Vol 62 (12) ◽  
pp. 754-760
Author(s):  
Chao-Chen Yang ◽  
Min-Fong Shu
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Electrochemical Behaviour ◽  
Close Packing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molten Electrolyte ◽  
Transmission Electron ◽  
Molten Salt Electrolyte ◽  
High Level

The electrochemical behaviour of zinc on copper, platinum, and tungsten working electrodes was investigated in a binary ZnCl2-DMSO2 room temperature molten salt electrolyte in the temperature range of 60 - 80◦C. Various over-potentials, −0.1, −0.2, −0.3, −0.4, and −0.5 V, were chosen as deposition potentials. The nucleation/growth of zinc changed from progressive to instantaneous if the over-potentials increased from low to high level. The surface morphology and crystal structure of the deposited layer were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Moreover, larger grain size and hexagonal close packing of the zinc layer at −0.5 V were observed by transmission electron microscopy (TEM) with electron diffraction mapping.

Effect of Molybdenum and Ruthenium on the Crystallization Tendency of a New Nuclear Glass Containing High Rare-earth Concentration

2010 ◽  
Vol 1265 ◽  
Author(s):  
Daniel Caurant ◽  
Nolwenn Chouard ◽  
Odile Majerus ◽  
Jean-Luc Dussossoy ◽  
Aurelien Ledieu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Nucleating Agent ◽  
High Level Waste ◽  
Optical Absorption Spectroscopy ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Level ◽  
The Impact ◽  
Crystallization Tendency

AbstractThe impact of Nd2O3, MoO3 and RuO2 addition on the competition between the crystallization of apatite Ca2Nd8(SiO4)6O2 and powellite CaMoO4 phases which both may appear in High Level Waste nuclear glass (under certain specific conditions of cooling and glass composition) has been studied on a simplified composition belonging to the system SiO2-Na2O-CaO-Al2O3-B2O3. X-ray diffraction (at room temperature and high temperature) and scanning electron microscopy measurements have been performed on five glasses under two different thermal treatments. We show that RuO2 acts as a nucleating agent for apatite. Moreover, neodymium and molybdenum cations seem to be very close in the glassy network as Nd2O3 addition stops the phase separation of molybdates and inhibits the crystallization of CaMoO4. On the contrary, MoO3 seems to favor the crystallization of apatite. For several samples, the evolution of the distribution of Nd3+ cations after crystallization was followed by optical absorption spectroscopy.

High Temperature Wear of Ti3AlC2 Sliding against Al2O3

2010 ◽  
Vol 177 ◽  
pp. 118-120 ◽  
Author(s):  
Feng Jiang ◽  
Shu Fang Ren ◽  
Jun Hu Meng ◽  
Jin Jun Lu
Keyword(s):  
Sliding Wear ◽  
Friction And Wear ◽  
Room Temperature ◽  
Oxidation Layer ◽  
X Ray ◽  
High Temperature Wear ◽  
Increasing Temperature ◽  
Wear Transition ◽  
Worn Surface ◽  
Scanning Electron

Bulk Ti3AlC2 was prepared via hot pressing TiC, Ti and Al powders in vacuum. The sliding wear of Ti3AlC2 against Al2O3 at room temperature up to 800°C was investigated on a SRV-IV oscillating friction and wear tester. Reduced wear and wear transition of Ti3AlC2/Al2O3 tribo-couple were found by increasing temperature. The worn surfaces of both Ti3AlC2 and Al2O3 were analyzed by scanning electron microscope and X-ray photoelectron spectrometer. It was found that the severe wear of Ti3AlC2 and Al2O3 from room temperature to 200°C was related to mechanical wear, i.e. grain fracture and pullout of Ti3AlC2. At temperature higher than 400°C, the tribo-oxidation layer on the worn surface of Ti3AlC2 containing TiO2 and Al2O3 was beneficial for reducing wear of both Ti3AlC2 and Al2O3.

Effect of Hardness and Position on Wear Behavior of Steel Pairs

2012 ◽  
Vol 263-266 ◽  
pp. 95-98
Author(s):  
Zhu Jun Li ◽  
Zheng Wu Jiang ◽  
Huan Wei Zhou
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Room Temperature ◽  
Wear Behavior ◽  
Friction Pair ◽  
Wear Volume ◽  
Average Value ◽  
Small Impact ◽  
Test Conditions ◽  
The Coefficient Of Friction

In this paper, the effect of hardness and position on the 40CrNiMoA steel and 18Cr2Ni4WA steel friction pairs’ friction coefficient and wear volume were studied without lubrication, at room temperature. The results show that: Under test conditions, the fluctuation in the friction coefficient is bigger, when the up specimen is the harder 18Cr2Ni4WA steel. And when the up specimen is the softer 40CrNiMoA steel, the fluctuation in the friction coefficient is relatively small. When the up specimen is the 40CrNiMoA steel, the hardness of 40CrNiMoA steel is a relatively small impact on the average value of the coefficient of friction.When the up specimen is the softer 40CrNiMoA steel, the coefficient of friction is relatively larger than that when the up specimen is the harder 18Cr2Ni4WA steel. The wear volumes is relate to the position of friction pair. When the up specimen is the harder 18Cr2Ni4WA steel, both sides of the friction pairs has the same wear volumes when the hardness of 40CrNiMoA steel is about 43HRC. When the up specimen is softer 40CrNiMoA steel, and its hardness is about 54HRC, the wear volumes curves of two materials intersect.

Effect of silver-organic precursor on friction and wear

2014 ◽  
Vol 66 (3) ◽  
pp. 468-472 ◽  
Author(s):  
Ningning Hu ◽  
Jiguang Han ◽  
Bo Hu
Keyword(s):  
Design Methodology ◽  
Friction And Wear ◽  
Room Temperature ◽  
Tribological Behavior ◽  
X Ray Diffraction ◽  
Organic Precursor ◽  
Content Type ◽  
X Ray ◽  
Mild Wear ◽  
Boundary Films

Purpose – The purpose of this paper is to study the effect of silver (Ag) precursor on friction and wear. Design/methodology/approach – Thermogravimetric analysis of the oil with Ag precursor and X-ray diffraction of the decomposition product of the Ag complex were performed. The tribological behavior was evaluated on a UMT-3M Tribometer (CETR) using pure military-grade oil lubricant and the prepared lubricant at room temperature and at 300°C. Energy-dispersive spectroscopy of the chemical composition on the wear scar was performed. Findings – When there is 1 weight per cent Ag precursor in the lubricant, the coefficient friction reduces by about 8 per cent at room temperature and by about 14 per cent at 300°C, and the wear probability also decreases, from moderate wear to mild wear at 300°C. There were more productions which could form metal Ag boundary films possessing low shearing stress and excellent lubricity at 300°C. Originality/value – Ag precursors used as additives in a military-grade oil lubricant and excellent lubricity found at high temperature.

Electron Microscopy of Human Gallstones

1971 ◽  
Vol 29 ◽  
pp. 296-297
Author(s):  
C. Wolpers ◽  
R. Blaschke
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bile Pigment ◽  
X Ray Diffraction ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Follow Up Study ◽  
Infra Red ◽  
Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

Opening images of synaptic vesicles and calcium localization by means of microwave fixation method

1990 ◽  
Vol 48 (2) ◽  
pp. 182-183
Author(s):  
Vinci Mizuhira ◽  
Hiroshi Hasegawa
Keyword(s):  
Synaptic Vesicles ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Sampling Procedure ◽  
Fixation Method ◽  
Potassium Oxalate ◽  
X Ray ◽  
Cacodylate Buffer ◽  
Ultrathin Sections ◽  
Microwave Fixation

Microwave irradiation (MWI) was applied to 0.3 to 1 cm3 blocks of rat central nervous system at 2.45 GHz/500W for about 20 sec in a fixative, at room temperature. Fixative composed of 2% paraformaldehyde, 0.5% glutaraldehyde in 0.1 M cacodylate buffer at pH 7.4, also contained 2 mM of CaCl2 , 1 mM of MgCl2, and 0.1% of tannic acid for conventional observation; and fuether 30-90 mM of potassium oxalate containing fixative was applied for the detection of calcium ion localization in cells. Tissue blocks were left in the same fixative for 30 to 180 min after MWI at room temperature, then proceeded to the sampling procedure, after postfixed with osmium tetroxide, embedded in Epon. Ultrathin sections were double stained with an useal manner. Oxalate treated sections were devided in two, stained and unstained one. The later oxalate treated unstained sections were analyzed with electron probe X-ray microanalyzer, the EDAX-PU-9800, at 40 KV accelerating voltage for 100 to 200 sec with point or selected area analyzing methods.

Evidence for ordered Fe3Ni

1987 ◽  
Vol 45 ◽  
pp. 216-217
Author(s):  
K.B. Reuter ◽  
D.B. Williams ◽  
J.I. Goldstein
Keyword(s):  
Experimental Data ◽  
Martensitic Transformation ◽  
Electron Diffraction ◽  
Room Temperature ◽  
Direct Evidence ◽  
Transformation Product ◽  
Iron Meteorites ◽  
X Ray ◽  
Ni Content ◽  
Temperature Transformation

In the Fe-Ni system, although ordered FeNi and ordered Ni3Fe are experimentally well established, direct evidence for ordered Fe3Ni is unconvincing. Little experimental data for Fe3Ni exists because diffusion is sluggish at temperatures below 400°C and because alloys containing less than 29 wt% Ni undergo a martensitic transformation at room temperature. Fe-Ni phases in iron meteorites were examined in this study because iron meteorites have cooled at slow rates of about 10°C/106 years, allowing phase transformations below 400°C to occur. One low temperature transformation product, called clear taenite 2 (CT2), was of particular interest because it contains less than 30 wtZ Ni and is not martensitic. Because CT2 is only a few microns in size, the structure and Ni content were determined through electron diffraction and x-ray microanalysis. A Philips EM400T operated at 120 kV, equipped with a Tracor Northern 2000 multichannel analyzer, was used.

Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

1990 ◽  
Vol 48 (4) ◽  
pp. 172-173
Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito
Keyword(s):  
Phase Transition ◽  
Electron Microscope Study ◽  
Room Temperature ◽  
Hexagonal Lattice ◽  
Ferroelectric Materials ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Periodic Arrays ◽  
Modulation Wave Vector

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.

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