Molten metal casting die
View Patent ↗A molten metal casting die having a modified surface, a method for making such dies, and a method for making articles of manufacture from such dies is disclosed. The methods are designed to protect die steel surfaces having a protective coating from corrosion by molten metals substantially containing liquid copper.
1. A method for protecting the surface of a die useful for casting of copper articles, comprising providing a steel die and applying a protective coating to a surface of the die which coating is to be in contact with molten copper, wherein the protective coating comprises a transitional layer comprising Al 2 O 3 in contact with the steel die; a second layer comprising MoSi 2 +Al 2 O 3 in contact with the transitional layer; and a third layer comprising NiCr—Cr 3 C 2 in contact with the second layer.
2. The method of claim 1 , wherein the steel is H-13 steel.
3. The method of claim 1 , wherein the protective coating has a thickness in the range of from about 100 microns to about 400 microns.
4. A die for casting copper articles, comprising
a die substrate comprised of a steel surface; and
a protective coating comprising a transitional layer comprising Al 2 O 3 in contact with the steel surface; a second layer comprising MoSi 2 +Al 2 O 3 in contact with the transitional layer; and a third layer comprising NiCr—Cr 3 C 2 in contact with the second layer;
wherein the coating is adapted to contact molten copper when casting a copper article in the die.
5. The die of claim 4 , wherein the steel surface is H-13 steel.
6. The die of claim 4 , wherein the protective coating has a thickness in the range of from about 100 microns to about 400 microns.