While we were waiting for the anode to arrive, we ordered the material for the next anode beyond that, so we won’t be waiting for it when we need it. After thorough discussion with beryllium experts, we’ve chosen a grade of beryllium metal that’s almost twice as strong as the one we’re using now.
Beryllium metal parts are made by pressing together beryllium powder under high pressure. Melting beryllium and casting it produces a very weak structure, so that method is never used. The new material, called I-220-H by beryllium manufacturer Materion, is made stronger by the high temperatures at which the powder is pressed together, as well as the fine size of the powder used. The result is that I-220-H has porous voids that take up only 0.3% of the volume, while the grade that we were using, S-200-F, had voids that took up 1% of the volume. Combined with a tiny amount of beryllium oxide, the lesser porosity makes for greater strength.
This doubled strength will come in handy when, after the next set of experiments, we upgrade our FF-2B to its full power. We’ll be increasing its current by 50%, which will about double the thermal stress on the anode. With double the tensile strength, the anode we’ll make from the new material will be able to take the stress.
Of course, with greater strength comes greater expense; Materion prices this material at almost exactly twice what we paid for the old grade – $17,000 for the material for one anode. So again, this is why we need to be meeting our goals on fundraising. We need $500,000 total by the end of the campaign in just a week.
Our old anode, shown here, was about as strong as stainless steel. The material we are ordering now is nearly twice as strong.