ELECTROCHEMICAL BEHAVIOUR OF Al-BRASS IN SEAWATER
Corrosion of the Al-brass in 3.5 % NaCl solution and natural seawater was investigated with potentiodynamic polarization technique. Corrosion rate obtained in natural seawater was higher than in 3.56 % NaCl solution. The metallographic examinations indicated the occurrence of pitting corrosion in both cases.
Impingement Corrosion of Condenser Tubes
AbstractThe problems of impingement corrosion of condenser tube materials are reviewed, with special reference to the power industry of the UK. The South Eastern Region of the Central Electricity Generating Board has set up a laboratory to study the corrosion behaviour inflowing sea water of metals used in power station cooling water systems. The jet impingement facilities of the laboratory are described and the results of recent work presented. These include the impingement characteristics of some standard condenser tube materials, the modification of these characteristics by such methods as cathodic protection and ferrous sulphate dosing of the sea water, and the resistance to impingement corrosion of some new materials. Particular attention is paid to titanium and its resistance to this form of corrosion.
Stability of planar PEMFC in Printed Circuit Board technology
Abstract The use of planar PEMFCs in printed circuit board (PCB) technology with a thickness of less than 3.5 mm are presented. This planar design consists of an open cathode side which allows a completely passive, self-breathing operation of the fuel cell. Power densities of 100 mW/cm 2 at 500 mV with hydrogen as a fuel were achieved. A steady operation with this type of fuel cell was demonstrated over a week without any cell flooding. Since the electrical conducting elements of PCBs usually are made of copper, corrosion in the wet environment of a PEMFC is expected. Thus, a significant degradation in performance of fuel cells made of plain copper PCBs was seen in long-term operation. In order to avoid corrosion, the copper layer has to be coated. Fuel cells in PCB design with diverse coatings were tested in long-term operations up to 1000 h under load. Moreover, corrosion currents have been determined by the use of potentiodynamic scans. Promising coatings are electroplated Cr and Ni and a combination of Ni/Au.