What you want to ask is the cause of pitting during sintering of silicon nitride substrate? When the mold shell is not baked through, the impurities in the refractory material increase.
1. When the mold shell is not baked through, a small amount of gas will be generated at the high temperature during pouring, which will promote the occurrence of interface reactions and form pitting.
2. The increase of impurities in refractory materials, especially the excessive Fe2O3 content, will directly lead to its participation in the interface reaction between the mold shell and the molten steel, causing oxygen to enter the molten steel and cause secondary oxidation, thus increasing the The tendency of pitting.