Study on the preparation of copper red glaze and parameters affecting its colour

Copper red glaze is one of the traditional famous glazes in China, its colour effects depend on many combined factors. In this paper, the technological parameters in the preparation process were studied by experiments, and the suitable preparation process of copper red glaze was determined. The preparation process is as follows: the use of kaolin, quartz and feldspar as the main raw materials, copper oxide as a colourant, batching, ball milling (material:ball:water = 1:1:1, 15 minutes), sieving (250 meshes), glaze impregnation (15 s - 30 s). The firing process is as follows: heating up in an oxidizing atmosphere for 2 hours to the atmosphere conversion temperature, conversion to a strong reduction temperature - slow increase to 1200 °C, conversion to a weak reduction - slow increase to the highest firing temperature, holding for 10 minutes, ceasing the firing, furnace cooling. The main factors affecting the colour of copper red glaze were studied. The experimental results show that not only the content of copper ion in the glaze and the firing atmosphere, but also the content of potassium feldspar, kaolin and quartz has a significant influence on the colour of the copper red glaze. The chromaticity values of the samples were measured and the internal mechanism of influence was preliminarily discussed based on the results of SEM and EDS analysis.