The Effect of Pulsed Current and Organic Additives on the Hydrogen Incorporation in Electroformed Copper Used in High Vacuum Applications

The presence and influence of hydrogen on electroformed copper from two different acidic copper sulfate solutions was evaluated: an additive-free solution and a solution including a sugar. D-xylose addition is found to inhibit the H2 formation and allows using higher cathodic pulses before the starting of the copper diffusion limited range. TDS experiments show the release of hydrogen trapped into the copper under two different forms. Hydrogen diffused from copper vacancies was found on all samples at an outgassing temperature around 450°C. For samples with long pulse times, an additional H2 outgassing peak was found around 600°C. XRD measurements allowed us to determine the preferential orientation of the plated samples and to monitor the lattice parameter evolution with increasing temperature.