摘要:

AbstractWear in modern mechanical systems is characterised by ultra‐low wear rates in the range of a few nanometres per hour. Both the surfaces of the materials involved and their volumes undergo modification as regards morphology, crystalline arrangement, and chemical composition. The depth of tribological interactions for given conditions is in the order of a micrometre or less. Synchrotron‐based X‐ray diffraction and nano‐indentation were used to probe these thin modified zones. The specimens were taken from tribometric experiments employing the radionuclide technique as the ultimate tool to measure ultra‐low wear rates. To obtain different degrees of tribological interaction various loads and sliding velocities were applied. The specimens were classified according to the total power dissipated during the tribometric e

ISSN:1354-4063    

DOI:10.1002/tt.3020110202

出版商:John Wiley&Sons, Ltd    

年代:2004

数据来源: WILEY

摘要:

AbstractHigh‐temperature‐resistant self‐lubricating coatings are needed in space vehicles for components that operate at high temperatures and/or under vacuum. Thick composite lubricant coatings containing quasicrystalline alloys as the hard phase for wear resistance can be deposited by a thermal spray technique. The coatings also contain lubricating materials (silver and BaF2CaF2 eutectic) and NiCr as the tough component. This paper describes the vacuum tribological properties of TH103, a coating of this type, with a very good microstructural quality. The coating was deposited by high‐velocity oxygen fuel spraying and tested under vacuum using a pin‐on‐disc tribometer. Different loads, linear speeds, and pin materials were studied. The pin scars and disc wear tracks were characterised using a combination of scanning electron microscopy and energy dispersive spectrometry. A minimum mean steady friction coefficient of 0.32 was obtained when employing an X750 Ni superalloy pin in vacuum conditions under 10 N load and 15 cm/s linear speed, showing moderate wear of the disc and low we

ISSN:1354-4063    

DOI:10.1002/tt.3020110203

出版商:John Wiley&Sons, Ltd    

年代:2004

数据来源: WILEY

摘要:

AbstractThe elastohydrodynamic traction coefficients of two Chinese aviation lubricating oils were investigated for various loads, rolling velocities, and lubricant inlet temperatures using a self‐made test rig. Traction coefficient versus slide‐to‐roll ratio curves were generated. The concept of critical load varying with the lubricant temperature is proposed. This paper presents a new empirical formula for the dynamic performance design of high‐speed rolling bearings, that relates traction coefficient with normal load, rolling velocity, and lubricant inlet temperature. The coefficients of the formula may be computed by regression analysis of the experimental data. Two example calculations are presented. The predicted results from the formula agree well with experimental obser

ISSN:1354-4063    

DOI:10.1002/tt.3020110204

出版商:John Wiley&Sons, Ltd    

年代:2004

数据来源: WILEY

摘要:

AbstractThe aim of this study has been to develop a new method of recording temperature fields over friction surfaces and within thin surface layers of friction pair elements. In this, the materials tested include steel, titanium, aluminium, silica glass, and sapphire. When studying the temperature distribution in the surface layers of mated bodies a pin‐on‐disc geometry is used. The friction regimes are as follows: the sliding velocity is varied within the range 10–80 m/s and the nominal pressure is 0.06–0.5 MPa. Experiments have been performed using a set‐up involving an optoelectronic scanning technique and comprising a high‐speed friction machine and a temperature field recording system. The latter consists of an optoelectronic transducer, a monitor, a video tape recorder, an amplifier, a device to form oscillograms of image brightness, and a digital storage o

ISSN:1354-4063    

DOI:10.1002/tt.3020110205

出版商:John Wiley&Sons, Ltd    

年代:2004

数据来源: WILEY

摘要:

AbstractThe aim of this paper is to illustrate the similarities and variations between friction and wear data acquired with two different types of laboratory tribological test equipment that not only operate in the gap between macro‐ and nano‐testing, but also provide test parameters that allow an overlap across the whole scale from macro‐ to nanoscale friction and wear tests. Comparative wear tests were conducted under identical test conditions in the overlap region between macro‐ and micro‐regions using an existing piece of laboratory fretting test equipment and a novel one. The experimental test data obtained with these two experimental set‐ups ar

ISSN:1354-4063    

DOI:10.1002/tt.3020110206

出版商:John Wiley&Sons, Ltd    

年代:2004

数据来源: WILEY

摘要:

AbstractA study of the formation of gouging pits in Mn7Cr2steel under impact abrasive wear conditions was conducted using theories of elastic impact and contact, analysis of photo‐elasticity, and scanning electron microscopy (SEM). The results show that the maximum shear stress occurs at z = 0. 48a, and this initiates a crack; the crack propagates at an angle of 45° from the horizontal; and the gouging pit is conical. The SEM observations are in agreement with the theoretical calculatio

ISSN:1354-4063    

DOI:10.1002/tt.3020110207

出版商:John Wiley&Sons, Ltd    

年代:2004

数据来源: WILEY

ISSN:1354-4063    

DOI:10.1002/tt.3020110208

出版商:John Wiley&Sons, Ltd    

年代:2004

数据来源: WILEY

ISSN:1354-4063    

DOI:10.1002/tt.3020110209

出版商:John Wiley&Sons, Ltd    

年代:2004

数据来源: WILEY

ISSN:1354-4063    

DOI:10.1002/tt.3020110201

出版商:John Wiley&Sons, Ltd    

年代:2004

数据来源: WILEY