friction-stir welding process is a novel method of solid state welding, which produces heat due to friction between the pin, the shoulder and the workpiece. this heat causes a paste area. shoulder pressure and pin spin cause edges integration and lead to welding. in this study, firstly, the feasibility of welding of steel sheet (en10130) with a thickness of 1.5mm has been tested by 58 experimen...

Three experiments investigated whether 14- and 15-month-old infants use information for both friction and slant for prospective control of locomotion down slopes. In Experiment 1, high- and low-friction conditions were interleaved on a range of shallow and steep slopes. In Experiment 2, friction conditions were blocked. In Experiment 3, the low-friction surface was visually distinct from the su...

Friction reduction is necessary in order to decrease engine emissions, so bearing friction needs to be reduced but with the constraint that low friction solutions should not affect bearing reliability. To meet this target of low friction and high reliability bearings, several technical solutions are reviewed. Particular attention is paid to evaluating friction reduction performance for each sol...

This paper aims to investigate the microscopic friction mechanism based on in situ microscopic observation in order to record the deformation and contact situation of friction lining during the frictional process. The results show that friction coefficient increased with the shear deformation and energy loss of the surfacee, respectively. Furthermore, the friction mechanism mainly included adhe...

In some engineering fields, wear resistance and a low friction coefficient are required at the sametime. In this research, PTFE nanoparticles and carbon nanotubes were co-deposited within Ni-Pmatrix to obtain an Ni-P-PTFE-CNT hybrid coating for wear resistance and a low friction coefficient.The tribological properties of the deposits were evaluated by pin on disc tribometer. T...

A friction coefficient is defined as the ratio of the friction force to the applied normal force. Despite the disarming simplicity of its calculation, there are practical challenges that make low values of friction coefficient difficult to accurately quantify. The connections of imperfect parts in friction measurement devices (called tribometers) produce small misalignments between the transduc...

Friction measurements have been performed on microcrystalline, ultrananocrystalline, and diamond-like carbon DLC films with natural diamond counterfaces in the temperature range of 8 K to room temperature. All films exhibit low friction 0.1 in air at room temperature. In ultrahigh vacuum, microcrystalline diamond quickly wears into a high friction state 0.6 , which is independent of temperature...

I. Preliminary Remarks A. Introduction B. Some Fundamental Definitions and Questions C. Basic Scenarios for Friction D. Phenomenology of Static and Low-Velocity Kinetic Friction II. Rigid Walls A. Geometric Interlocking B. Thermal Effects C. Applications 1. Nanotubes 2. Curved, Nanoscale Contacts III. Dry, Elastic Friction A. Properties of the Prandtl–Tomlinson Model 1. Definition of the Model ...

In this paper, we investigate the sliding friction and wear behavior of a hydrogenated diamond-like carbon (DLC) film in ultrahigh vacuum (UHV) and under partial pressures of water vapor, oxygen, nitrogen and hydrogen. The initial friction coefficient of the film in UHV was 0.15, but decreased steadily to values as low as 0.03 after about 30 sliding passes. During longer duration tests, the fri...