Hello >From my chemistry days I think there is a complementary explanation to the coating of cathodes with Mercury and for mercury vapor inside the Nixie. It takes less energy to energize mercury atoms than energizing the atoms in the penning mix (Neon and Argon). This principle also led to the development of the fluorescent tube. In this way the mercury atoms form part of the thermionic emission releasing electrons with UV wavelenghths which collide with and ionize the noble gas atoms inside the tube to form the resulting plasma by the process of impact ionization. As a result of avalanche ionization the ionized gas increases its conductivity rapidly and a current is able to flow. Mercury also has the benefit of stabilizing the ionization voltage as well as increasing the life of the cathode.
On Thursday, 13 February 2014 19:32:10 UTC+11, Dalibor wrote: > > Hi, the mercury adheres to cathode surface and because its molecule is > heavy, it is less likely to be relieved from the cathode by electrons > bombarding the cathode (compared to relatively light molecules of Fe, > Ni, Cr - stainless steel).. The lifetime of mercury doped nixies is > 200.000 hrs, tubes without mercury have 5.000 hrs (MTBF value from > datasheets). This is a theory.. The lifetime otself depends on many > other parametrs, eg. size of the hole in anode grid or shape of the > ceramic insulators between numbers.. > > My experimental tube without mercury is at ~1500 hrs, no signs of > metal deposit on glass, some deposit of shiny metal on ceramic > insulators - the resistivity is not measurable yet (>300 Mohms). > photo: http://tinyurl.com/n5o5bau > > Dalibor > > 2014-02-13 8:44 GMT+01:00 Kevin Keith <[email protected] <javascript:>>: > > I've seen references and claims to this fact, but never an explanation > of the exact mechanism? So, with that said, how *does* mercury actually > reduce cathode poisoning/sputtering damage? Are there any potential > alternatives? Would something like gallium work? > > > > -- > > You received this message because you are subscribed to the Google > Groups "neonixie-l" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to [email protected] <javascript:>. > > To post to this group, send an email to > > [email protected]<javascript:>. > > > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/61e65e8a-43ac-4cc4-824b-04c7f4039731%40googlegroups.com. > > > > For more options, visit https://groups.google.com/groups/opt_out. > > > > -- > Dalibor Farny > ---------------------------------------- > phone: +420 724 321 571 > http://www.daliborfarny.com > blog: http://dalibor.farny.cz > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/c463dde4-e49f-4be6-bbe3-895526ef57e9%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
