| abstract |
A method for the production of a crack-free, internally vitrified SiO2 crucible, in which an amorphous, open-pored SiO2 green-body crucible is sintered by means of a focal spot of a CO2 laser beam, wherein the focal spot is moved relative to the crucible throughout the sintering, the sintering being started at the upper inner edge of the SiO2 green-body crucible by means of a point-like focal spot and being continued with the point-like focal spot broadening to the intended focal-spot size, the focal spot sweeping over the upper inner edge of the SiO2 green-body crucible until the upper inner edge is fully vitrified, and the focal spot then moving into the SiO2 green-body crucible. |