I am trying to sinter my samples at 1300 degree celsius in Vacuum and I came to know about a technique from some lab technicians that it can be done using box or muffle furnace itself. The idea is is to keep your samples in a silicate glass tube, creat vacuum inside it and seat it. Then perform the sintering in normal muffle furnace. But I can not find any supporting jourals to back up this method. Can someone help me with links to such research papers if anyone has come across with such papers?