Protective layer, composite for forming the protective layer, method of forming the protective layer, and plasma display panel including the protective layer

A composite for forming a protective layer, the composite comprising:

• a magnesium oxide component derived from at least one magnesium-containing compound selected from the group consisting of magnesium oxide and magnesium salts;
• a rare earth element component derived from at least one rare earth element-containing compound selected from the group consisting of the rare earth element oxides and the rare earth element salts;
• and
• a chromium component derived from at least one chromium-containing compound selected from the group consisting of chromium oxide and chromium salts.

A method of forming a protective layer, the method comprising:

• substantially uniformly mixing at least one magnesium-containing compound selected from the group consisting of magnesium oxide and magnesium salts and at least one rare earth element-containing compound selected from the group consisting of the rare earth element oxides and the rare earth element salts;
• calcinating the resultant mixture;
• sintering the calcined resultant mixture;
• and
• forming a protective layer using the composite.

A method of forming a protective layer, the method comprising:

• substantially uniformly mixing at least one magnesium-containing compound selected from the group consisting of magnesium oxide and magnesium salts, at least one rare earth element-containing compound selected from the group consisting of the rare earth element oxides and the rare earth element salts, and at least one chromium-containing compound selected from the group consisting of chromium oxide and chromium salts;
• calcinating the resultant mixture;
• sintering the calcined resultant mixture;
• and
• forming a protective layer using the composite.