Dear Sekaran,

I think mild HCl solution (1:10 v/v HCl:water) will be the best. This will not damage the crucible. After complete washing, you should wash the crucible with acetone.

Thank you.

You may find useful to check this RG discussions: https://www.researchgate.net/post/How_to_remove_metal_or_metal_oxide_thin_film_coated_on_alumina_substrate https://www.researchgate.net/post/How_to_wash_the_alumina_tubeWhich_chemical_is_best_for_washing_the_alumina_tube_so_that_no_cracks_form_on_surface_of_tube

Dear Sekaran,

I am also facing same problem, at that time I am using strong H2SO4 acid or HCl and wait 20 minutes cleaning after that.

Thank you.

I assume you heat your sample under pure inert gas (N2 or argon or helium). For the dissolution, you may try HCl (say, 1:1 or 20%) with very little HF (e.g. 1000-5000 parts 1:1 HCl and 1 part concentrated HF; I would start with 5000:1 and move toward 1000:1 if the more dilute mixture is not enough). The attack on alumina should be minimal.

However, if your gas contains oxygen, since both aluminum and titanium are good oxygen getters they will cover themselves with dense (high-temperature-annealed) oxide, and the dissolution will be much more difficult.

For the non-sticking part, you may want to get coarse alumina (sapphire) powder and line the bottom of your alumina crucible with it. I don't know whether you heat your sample high enough to melt a lot of aluminum - the more melting occurs, the more alumina powder you should use. At the end of the experiment, the metals should be removable together with the alumina powder.

Dear researchers thanks for the suggestion,

i have tried one of your options and succeeded in removing

thanks