Patent ID: 7776155

Claim:
A quartz glass crucible, comprising: a quartz glass crucible having a coating layer on an inside surface, wherein the coating layer consists of a metal oxide, wherein the metal oxide is at least one oxide selected from the group of oxides consisting of magnesium, calcium, strontium, and barium oxide, wherein the coating layer is a transparent structure integrated with the inside surface of the crucible, and wherein said coating layer is baked on at least a portion of an inside surface of said crucible, the coating layer of the metal oxide is baked on the surface of the crucible at a temperature of from 600° C. to 1,200° C. for from 10 to 120 minutes, and the coating layer of the metal oxide is baked on at least a portion of the inside of the crucible with a strength of a pencil hardness of at least 6H according to JIS 5600-5-4.