Ultra-low loadings of Au for stainless steel bipolar plates
View Patent ↗An electrically conductive fluid distribution element for a fuel cell which comprises an electrically conductive substrate, a flow field for distributing fluid along a surface of the substrate, and an electrically conductive coating on the surface which comprises a noble metal, desirably Ru, Rh, Pd, Ag, Ir, Pt, Os, and preferably Au.
1. An electrically conductive fluid distribution element, comprising a metal substrate and a noble metal coating on the substrate, the metal substrate having been simultaneously cleaned and coated with the noble metal coating by ion-assisted physical vapor deposition, the element having no oxide layer between the metal substrate and the noble metal coating, wherein said coating has a thickness of 10 to 20 nm.
2. An electrically conductive fluid distribution element according to claim 1 , wherein the noble metal coating comprises Au.
3. An electrically conductive fluid distribution element according to claim 1 , wherein the noble metal coating consists essentially of Au.
4. An electrically conductive fluid distribution element according to claim 1 , wherein the metal substrate comprises a member selected from the group consisting of stainless steel, aluminum, titanium, and foamed conductive metals.
5. An electrically conductive fluid distribution element, comprising a metal substrate and a noble metal coating on the substrate having a thickness of about 10 to about 20 nm, the metal substrate having been simultaneously cleaned and coated with the noble metal coating by ion-assisted physical vapor deposition, the element having no oxide layer between the metal substrate and the noble metal coating, wherein said coating has a contact resistance at 50 psi suitable for use in a fuel cell.
6. An electrically conductive fluid distribution element according to claim 5 , wherein the noble metal coating comprises Au and wherein the contact resistance is from about 1.5 to about 6.5 milliohms/cm 2 at pressures of 50 psi to 270 psi.
7. A fuel cell comprising the electrically conductive fluid distribution element of claim 1 .
8. A fuel cell comprising the electrically conductive fluid distribution element of claim 5 .
9. The electrically conductive fluid distribution element of claim 1 , the noble metal coating having a peak-to-valley range (Z) from about 1.000 micrometers to about 2.800 micrometers as measured by Atomic Force Microscopy (AFM).