| Автор | P V K Porgess |
| Автор | H Wilman |
| Дата выпуска | 1960-10-01 |
| dc.description | Surface structure, friction and wear are investigated and correlated in the case of abrasion of graphite by emery papers of particle diameter D=5 to 150 microns. For graphite and also for metals, the coefficient of friction μ of specimens approximately 1 cm long or more is low on the fine grades of emery, but rises rapidly with increasing D and then is practically constant at D>50 microns. The ploughing component μ<sub>p</sub> is concluded to be larger than the adhesion component μ<sub>a</sub> when D is of the order of 30 microns or more. Earlier views that μ<sub>p</sub> increases linearly with D and is always small are evidently incorrect.Electron diffraction shows that the abrasion causes a re-orientation of the graphite at and near the surface by plastic flow by slip on (0001). A [001] `fibre orientation' is developed (the usual compression texture) with its mean axis along the resultant of the normal load and the tangential frictional force, at tan<sup>-1</sup> μ (whatever the value of μ) to the specimen normal, towards the direction from which the abrasive particles came.The wear per unit distance M also rises rapidly with D and then shows a much slower rate of increase at D>80 microns. The plot of M against μ is a strongly curved locus at 200g load, and is still curved even at 25g load, for graphite; while for metals it is linear at least up to 2kg load (Goddard, Harker and Wilman 1959). The difference in nature of the abrasion is also seen microscopically; cracking and some breakaway of graphite fragments occurs near the individual grooves, and is associated with a volume-wear rate about four times that of metals, at D>50 microns.A method of comparing the hardnesses of the work-hardened surface regions of abraded materials in terms of abrasion-groove widths is described. For the graphite specimen used this is of the order of one-fifth that of silver; the effective Vickers hardness is thus of the order of 20, and this agrees with estimates made using a diamond indenter. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Surface Re-orientation, Friction and Wear, in the Unidirectional Abrasion of Graphite |
| Тип | paper |
| DOI | 10.1088/0370-1328/76/4/309 |
| Print ISSN | 0370-1328 |
| Журнал | Proceedings of the Physical Society |
| Том | 76 |
| Первая страница | 513 |
| Последняя страница | 525 |
| Аффилиация | P V K Porgess; Chemical Engineering Department, Imperial College, London |
| Аффилиация | H Wilman; Chemical Engineering Department, Imperial College, London |
| Выпуск | 4 |
