[en] Effect of calcium and magnesium fluoride additions on phase composition and poperties of sintered ceramics on zirconium dioxide base is investigated. It is stated that fluoride additions, stabilizing ZrO₂, promote some densification of the samples during annealing with 20-30% decrease of open porosity, but mechanical strength remains not high. Necessity of limiting calcium and magnesium fluoride adding to ceramics due to formation of gaseous fluorine compounds and necessity of constructing purification structures for high fluoride addition sintering is pointed out