Quicker, faster, smaller and stronger are words that dictate the basic parameters set for next generation products in most industry sectors.
Components are increasingly required to operate under more extreme or hotter conditions. This puts demands on the materials and their performance.
For example, metalized carbon products used in rail pantographs demand continued research and development to produce the next generation materials with low friction, an ability to withstand high temperatures and take high current.
Recently, two important research projects have been carried out to enhance the physical properties of materials employed in rail pantographs.
Wet Weather Running Conditions
During the colder months of the year, many regions are affected by a combination of wet and cold weather conditions, resulting in the formation of ice on overhead rail lines.
The ice acts as a barrier between the carbon and the overhead line. This produces an arc to be drawn to the aluminum carrier. The metal carrier begins melting as a result of the heat from the arc, and eventually needs replacing before the carbon becomes too worn. This increased carbon wear will increase running and lifecycle costs.
Morgan Advanced Materials has been developing and testing a metalized carbon current collector with an arc protection coating to avoid premature wear caused when and electric arc is drawn to the metal carrier. Figure 1 shows the metalized carbon current collector with arc protection coating.
Figure 1. Metalized carbon current collector with arc protection coating
The materials developed during this research were deployed at major rail carriers in the United Kingdom and Poland for two years of winter trials.
A collector strip without any arc protection coating, and subjected to severe arc damage along the aluminum carrier is shown in Figure 2.
Figure 2. No arc protection coating and severe arc damage
Figure 3 shows the new collector strip with the arc protection coating. The coating has protected the aluminum carrier from damage due to severe arcs during service.
Figure 3. Collector strip with arc protection coating
The operators of the UK line employed the new insulated coating designs following the experimental trails.
Improving Carbon Edge Chipping
A major user group is currently evaluating new carbon materials produced by Morgan to better resist carbon edge chipping.
The test was performed using Morgan’s high velocity impact test rig, which produces high velocity low mass impacts often resulting in chipped carbon edges during service. The collector was set at a 45 degree angle to ensure the projectile hit the carbon edge at the correct angle.
The tests were performed under Morgan recommended conditions so as to achieve the required energy for chipping both the carbons tested.
The impact damage in the carbons caused at two different conditions labeled 8 and 9 is shown in Figure 4. It was evident from the tests that the Morgan metal-impregnated carbon displayed better chip resistance.
Figure 4. Comparison of chipping in Morgan and market carbons
This information has been sourced, reviewed and adapted from materials provided by Morgan Advanced Materials.
For more information on this source, please visit Morgan Advanced Materials.