Anomalous Heat Generation by Surface Oxidized Pd Wires in a Hydrogen Atmosphere

Thin Pd wires (diameter 50 micrometers) surface oxidized through Joule heating have been loaded in a Hydrogen atmosphere at pressures in the range 1 - 10 bar. The atomic ratio H/Pd reached in the experimental conditions has been evaluated through its relationship with the electrical resistivity of Hydrogen loaded Pd. It was found that the loading rate of the surface oxidized Pd wires is exceptionally higher than with the untreated ones (full loading in a few minutes as compared with several hours). It was also observed that surface treated wires with H/Pd ≥0.75, don't lose Hydrogen even when Joule heated at temperatures up to about 150 °C in a Hydrogen atmosphere. When the wire temperature exceeds 150 °C (applied power about 12.4 W) there is an anomalous heat generation (about 3.5 W). During an experimental test, comprising feeding the wire with stepwise increasing power values each for 500-600 seconds, followed by a period of zero power, it was observed that when the power was cut off after the period of powering with 14 W, the wire spontaneously heated for about 70 seconds releasing an estimated heat of 1650 ±; 160 J, corresponding to 3940 ±; 400 Kcal per mole of Pd. Peak power was ~ 16 W. The wire resistance spontaneously reaches a value R/Ro = 2.40 and then slowly dropped to the original value of 1.80 at room temperature. In a second experimental test with the same wire similar phenomena have been observed although of lower intensity but lasting over 3000 seconds. After 16 W powering for 500 seconds, the power was cut off. Again the wire heated spontaneously releasing an anomalous heat of 3600 ±; 360 J, corresponding to some 13200 ±; 130 Kcal per mole of Pd. The peak power was ~ 3 W. The wire resistance increased spontaneously up to R/Ro = 2.01 and then slowly decreased down to 1.90.