Material Science on Pd-D System to Study the Occurrence of Excess Power

A recent joint work [1] identified the crucial role of material science in improving control of the Pd-D system to enhance the production of excess power during electrochemical loading of palladium foils with deuterium. Very high reproducibility, close to 100%, in loading Pd up to D/Pd ~1 (atomic fraction) was achieved. High loading about the threshold value of 0.9 is considered necessary to achieve the effect. This work demonstrated it is necessary but not sufficient. As a consequence, the focus of our research moved to the material properties of cathodes, especially surface characteristics, and an effort to correlate these properties with cathode performance during electrolysis. This paper describes the material properties examined that appear to produce excess heat. Introduction Recent evidence indicates that the Pd material plays a fundamental role in the occurrence of excess heat production during electrochemical loading of palladium cathodes with deuterium. This evidence has created a mounting interest in aspects of research related to material science. A broad effort was carried out in the past to identify the mechanisms controlling hydrogen isotope dissolution into the palladium lattice during the loading process. The study helped define a proper metallurgical treatment to obtain the most suitable metallurgy to facilitate hydrogen absorption into the palladium cathode [2]. This work generated almost 100% reproducibility in achieving a deuterium concentration larger than 0.9 (atomic fraction) that is considered to be the threshold value for observing the effect. This experimental work also demonstrated that the concentration threshold is a necessary condition for excess heat production, but not necessarily a sufficient one. Such evidence led to a systematic effort to improve knowledge about the status of the material that is required to have the effect. Let us start from the most significant experimental evidence obtained from a statistical analysis of the data. Three different behaviors were observed with Pd cathodes loaded above the threshold D/Pd = 0.9: (1) High power gain during the excess. (2) Low power gain during the excess. (3) No excess.