Volume 53, Issue 12

The materialographic investigation of anode materials for rechargeable lithium ion batteries is a significant step in the understanding and development of electrode materials, but made dramatically more difficult due to the high reactivity of the materials involved. In this work a method is presented which permits the metallographic preparation of the lithium-carbon intercalation compounds used as anode materials in today's rechargeable lithium ion batteries, and which allows the details of their microstructures to be contrasted. After classic, but absolutely water free, preparation in a protective gas atmosphere, the final stage of preparation is carried out using both ion beam polishing and manual polishing on a stationary polishing disc, whereby no significant differences of the quality of the microstructural images obtained is apparent.

The control chart data analysis approach is an ideal method to evaluate the quality of test data using a specific tester, such as a microindentation hardness tester, over a period of usage time. The method described in ASTM E2554 was used for this work. This analysis is done by plotting a Mean s and a standard deviation control chart of the weekly/periodic verification data obtained with certified hardness test blocks at a specific test force and a specific hardness level. The method is illustrated using a Knoop hardness test block certified at a test force of 500 gf and with a long diagonal length of 116.18 μm (527.1 HK). From this data, one can easily calculate the uncertainty of the measurements.

Cable car systems are predominantly used in the Alpine Region for the transportation of passengers and goods. During operation, their components are subjected to environmental influences as well as to static and dynamic loads. Even if standards, measurements, experimental tests, periodic inspections, and maintenance are considered, a component failure can not be entirely excluded. It is for that reason that cases of damage in the cable car industry are clarified based on systematic analyses aiming at prevention and an increase in security. The approach for the identification of the underlying causes of a case of failure is presented using the example of a spectacular incident in 2004 where all external profile wires of a support cable of a 100 passenger aerial tramway broke during operation. A precautionary and thorough preservation of evidence, detailed examinations of the subject components, clarifications of the operating history of the system, as well as an eventual identification of a probable damage process supported by examination findings are essential steps of this approach. The findings of such evaluations are the basis for recommendations regarding testing and construction of further systems, their operation, maintenance, and inspections with a focus on damage prevention.