"cleaning" alumina crucible

could anyone suggest me how to "clean" alumina crucible. i tried to sinter some powder at 800C and it left behind some coating inside the
crucible. tried using conc. acids, but not working well..any suggestions!!!
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Fasttrack wrote:

What powder did you try to sinter in an alumina crucible?
Michael Dahms
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Thanks Michael. it is some yttrium vanadates and also in other crucible some strontium borates.. Michael Dahms wrote:

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Fasttrack wrote:

You must check by separate experiments, which acids dissolve the above mentioned compounds.
Very often, a crucible can be just used once, if strong reactions with the sintered powder occur. Or a certain crucible is always used for a certain type of powder.
Michael Dahms
BTW: Please read http://www.xs4all.nl/~wijnands/nnq/nquote.html
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Thanks!!.
Michael Dahms wrote:

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