Failure analysis of Sm2Co17 type permanent magnet for high temperature
With the increasing using temperature, the magnetic performance of high temperature stable Sm2Co17 type permanent magnet will be decreased. In order to explore the effect of the high temperature on microstructure of the alloy, the differential thermal analysis (DTA) was made and three distinct phase transformation temperature 254 °C, 342 °C and 540 °C were obtained. Then X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray energy dispersive spectrometer equipped (EDS) were used to analyze the phase information, microstructure and composition of the samples treated at the above temperatures. The results suggested that the oxidation and precipitation of Cu and Fe are the key reason to result in the failure of the material, which provides an important reference for the research of the magnet.
Studies on corrosion conditions of metallographic sample of Sm_2Co_(17) permanent magnet materials
Sm2Co17 type permanent magnet materials were corroded under three kinds of corrosion conditions.Scanning electron microscopy and energy dispersive X-ray spectrometer were used to study the metallographic corrosion conditions.The result showed that sample corroded for 60 seconds in corrosive liquid of 100ml distilled water dissoled in 0.5ml nitric acid and 2ml acetic acid can clearly display boundary,surface of grain,and Zr-rich and Sm-rich phase in the grain.Compared with the corrosion agent most commonly used to metal material and the formula from metallographic corrosion handbook,the corrosion agent determined in this research can get a more clearly metallographic image.
Euthanasia — again: “Letting die” is not in the patient's best interests: a case for active euthanasia
Recent discussions in the Journal on the subject of euthanasia have relied on intuitive appeals to distinctions traditionally considered to be morally relevant, such as the distinction between acts and omissions (or killing and letting die), or ordinary and extraordinary means of treatment. These discussions remained inconclusive. However, the question of euthanasia no longer remains inconclusive if one adopts the perspective suggested by the United States President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research and by the World Medical Assembly – that a doctor should act in his or her patient's best interests. From this vantage point, it is argued, there will be instances when active euthanasia is the proper cause of action.