I see the logic of zirconia in hollow pipe - far stronger structure than a solid rod. But are we talking the metal (zirconium) or the ceramic (zirconia) - Zirconia is often used in bearings (i know this from radio control car racing)
My point being that ceramics are a more crystalline structure and can shatter (it can happend with zirconia bearings) - the zirconia is often used just as a coating. If it is zirconium alloy - how much is zirconium. Titanium is a funny material for cartridges and tonearms - the reason being that it is resilient and bendy - know this from mountain biking - that's why titanium front forks are rubbish as they don't give precise handling - that said when used in the main frame they are very light and comfortable.
My point being that ceramics are a more crystalline structure and can shatter (it can happend with zirconia bearings) - the zirconia is often used just as a coating. If it is zirconium alloy - how much is zirconium. Titanium is a funny material for cartridges and tonearms - the reason being that it is resilient and bendy - know this from mountain biking - that's why titanium front forks are rubbish as they don't give precise handling - that said when used in the main frame they are very light and comfortable.