Effect of Underglaze Paints as Cobalt and Nickel Salt Solutions on Porcelain Structure

The effect of underglaze paints in the form of cobalt and nickel salt solutions, especially in the porcelain-glaze contact zone, on the formation of the structure of a porcelain article was determined. In this zone the salts change the character and size of the new crystalline formations. As the color of the glassy layer of the glaze attests, the cobalt ions form compounds which are more soluble than nickel ions in the glass phase of porcelain and glaze. As the content of the salts increases, a crystalline paint layer forms on both sides of the article.