Title: Micromilling of bipolar fuel cell plates using titanium- and diamond-coated cutting tools

Authors: Mark J. Jackson, Grant M. Robinson, M.P. Brady, Waqar Ahmed

Addresses: Centre for Advanced Manufacturing, Birck Nanotechnology Centre, College of Technology, Purdue University, West Lafayette, IN 47907-2021, USA. ' Centre for Advanced Manufacturing, Birck Nanotechnology Centre, College of Technology, Purdue University, West Lafayette, IN 47907-2021, USA. ' Oak Ridge National Laboratory, Corrosion Science & Technology Group, Bethel Valley Road, Oak Ridge, TN 37831-6115, USA. ' Nanotechnology and Advanced Materials Research Centre, University of Ulster, Newtownabbey, Co. Antrim, Northern Ireland, BT37 0QB, UK

Abstract: Bipolar Proton Exchange Membrane Fuel Cell (PEMFC) plates are composed of flat pieces of graphite with channels or trenches machined into the face of the plate so that gases can flow in the channels of the plate. The operation of the fuel cell is dependent on the flow of oxygen and hydrogen gases around the fuel cell stack, which is composed of many thin plates connected to each other in very close proximity. Owing to the brittle nature of graphite, bipolar plates are now made from experimental Nickel–Chromium (Ni–Cr) alloys that are coated with a thin solid layer of CrN or TiN to improve corrosion resistance. However, Ni–Cr alloys are notoriously difficult to machine. This paper describes the micromachining of fuel cell plates that are machined at very high speeds in order to produce high cutting tool life and low surface roughness using novel nanocrystalline diamond and titanium coatings that have been specifically designed to cut strain-hardening alloys at extremely high speeds.

Keywords: nanostructured coatings; surfaces; metals; micromachining; machinability; fuel cells; nanomanufacturing; nanotechnology; micromilling; bipolar fuel cell plates; titanium-coated tools; diamond-coated tools; cutting tools; nickel–chromium alloys; tool life; surface roughness; high speed machining.

DOI: 10.1504/IJNM.2006.012200

International Journal of Nanomanufacturing, 2006 Vol.1 No.2, pp.290 - 303

Published online: 28 Jan 2007 *

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