My PhD thesis - Production of Aluminium Foams using Calcium Carbonate as a foaming agent
Conscious that this has become a little hard to find online, I thought it'd be worth posting a link to my PhD thesis, Production of Aluminium Foam using Calcium Carbonate as a Foaming Agent, from the Cambridge years, online. Because research is frankly no use unless people can access and build on it, and there's a fair bit in here about aluminium foams that's still interesting and relevant.
This was the first time that anyone had spent any real time looking into calcium carbonate as a way of making foams, and to cut a long story short it turned out to be a very cheap and cost effective way of doing it - because the gas produced was (oxidising) carbon dioxide rather than the more widely used (reducing) hydrogen gas, it made a thin layer of alumina on the aluminium cell walls and in doing so hugely stabilised the molten foam. This transformed what had previously been a pretty unstable production process, and meant that foams could be made on a far more industrial basis, with smaller cells.
The document is a whisker under 200 pages, and if you're printing it you'll be better off doing it in colour, for the (many) diagrams to make sense. Do feel free to cite it - the British Library citation reference is linked here. I'm still always happy to answer questions on it, though I don't work in this field any more so my memory's frankly pretty rusty on the subject!