Cutting of Rock by Wire-Sawing in Vacuum (3rd Report)
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2024-07-04 |
| Journal | Journal of the Japan Society for Precision Engineering |
| Authors | Katsushi Furutani, Ryota INUKAI, Tatsuaki Okada, Kazuto Saiki, Hiroyuki OHUE |
Abstract
Section titled āAbstractāThis paper investigates causes of the nickel adhesion during wire-sawing of rock by friction tests. In future planetary or asteroid explorations, wire-sawing is a solution for machining method for in-situ inspection. The authors have developed a compact wire-sawing machine which can be installed in a vacuum chamber. Electroplated nickel fixing diamond grits on a core wire adhered on the bottom of machined groove on a rock during wire-sawing in vacuum with the wire-sawing machine. In the experiments, specimens were rubbed with a probe in air, vacuum or argon atmosphere. A nickel sphere and diamond tip were used for the probes. Basalt and nickel plates were used for the specimens. In the friction tests of basalt with the nickel sphere, the average friction coefficients in air was larger than that in vacuum. By the component analysis by EDX (energy dispersive X-ray spectrometry), oxygen was detected on the surface of the nickel sphere tested in air. The friction tests of nickel plate with the diamond tip were also carried out. Nickel debris with oxidation was observed on the whole track after the friction test in air. In particular, flakes of several tens of micrometers were observed on the boundaries of the track. It was suggested that nickel became brittle by the oxidation so that it was removed with the diamond grits due to fracture. Plastic flow of nickel and less oxygen was seldom observed on the surface tested in vacuum and in argon atmosphere. Since the basalt is harder than nickel, the nickel was scraped off by the friction and became debris at pores on the basalt. In vacuum, the debris adhered and accumulated on the basalt surface without oxidation. Then, the nickel layer formed. Low oxygen concentration in atmosphere greatly caused the decrease of the removal amount.