Study On The Formation Of Fambe Glaze Of Jun Porcelain And Preparation Of The Celadon Glaze By Self-reduction Method

The origin and development of ceramics in China is closely related to the innovation of its preparation process,and the influence of firing temperature and atmosphere on ceramic quality is most prominent.In this paper,the causes and coloration mechanism of enamel enamel glaze formation under reducing atmosphere were studied.The process and technology of preparing celadon glaze by reduction method with silicon powder as reducing agent under oxidizing atmosphere were studied.Meanwhile,the neutral atmosphere was studied.Next,the method of preparing celadon glaze by self-reduction method,and using various modern testing and analysis methods,the reaction mechanism and coloration mechanism of celadon glaze prepared by self-reduction method were analyzed.Inthis study,underthereducingatmosphere,based on K₂O-Al₂O₃-CaO-SiO₂-P₂O₅ raw material lime alkali glaze,adding 1%iron oxide and 0.4%copper oxide as coloring agent,the same formula was used to produce a different color of fuchsia,blue-violet fambe glaze.The formation and coloration mechanism were studied by means of colorimetric analysis,phase analysis,microstructure and spectral analysis.Studies have shown that due to the different placement of the sample in the kiln,the firing temperature and atmosphere of the same formulation are different.The firing temperature of blue-violet glaze is higher than that of purple-red glaze;different temperatures lead to different shapes,sizes and arrangement of phase-separated structures.The blue-purple glaze with high temperature forms a regular opal-like phase separation and temperature.The low magenta glaze forms a worm-like structure.Compared with worm-like structure phase separation,the opal-like structure phase separation is more likely to promote the formation of blue enamel kiln glaze;different atmospheres cause the Fe³⁺part of the blue-violet glaze to transform into Fe²⁺,which is the main cause of glaze;CuSiO₃ and Cu₂O are formed in the red glaze,which together cause them to appear purple.The enamel color change of the enamel kiln is produced by the coupling of structural color and chemical color.Based on the K₂O-Al₂O₃-CaO-SiO₂ raw material lime alkali glaze under the oxidizing atmosphere,the basic glaze formula was determined by the four-corner batching method.On this basis,the effects of the celadon glaze process on the glaze surface by the self-reduction method were studied with the reducing agent silicon powder,the coloring agent iron oxide,the phase separation agent calcium phosphate and the firing temperature as variables.The intrinsic mechanism of the glaze was analyzed by means of XPS,UV-Vis spectrophotometer and TG-DSC.The research shows that the celadon glaze were successfully prepared by adding self-reduction method by adding silicon powder.The best formula is:24%frit,30%quartz,24%feldspar,8%calcite,5%kaolin,3%talc,4%zinc oxide,2%tin oxide,1%iron oxide,0.4%silicon powder The optimum firing temperature is:1250?;with the increase of the amount of reducing agent silicon powder added,the reaction between the silicon powder and the ferric oxide oxidation counter is more sufficient,so that the glaze changes toward the cyan direction.At the same time,the residual quartz in the glaze gradually increases and the size becomes larger.When the amount of silicon powder added exceeds 0.45 wt%,the glaze surface is defective;with the addition of the coloring agent ferric oxide,the silicon powder and the ferric oxide occur.The oxidation reaction is not completed,and triiron tetroxide is formed,which causes the glaze to develop toward the black tone,and the amount of residual quartz in the glaze is reduced.When the phase separation agent calcium phosphate is introduced,when the addition amount is increased from 0 wt%to 3 wt%,The CaFeO₂ crystals generated in the glaze increase,causing the glaze to face the blue tint transition;when the addition amount is increased from 3 wt%to 5 wt%,the glaze CaFeO₂crystals are reduced,resulting in a decrease in the glaze facing blue tone.At the same time,with the increase of phase separation agent,the residual quartz in the glaze increases,which leads to defects in the glaze;as the firing temperature increases,the glaze color changes with the redox reaction of silicon powder and ferric oxide.The residual quartz increases and grows with the redox reaction of silicon powder and ferric oxide between 1130?and 1220?.Between 1220?and 1280?,the residual quartz is gradually formed and grown.When the temperature is too high,the redox reaction proceeds violently,and the glazed surface glass phase is formed in a large amount,which causes defects in the glaze;the coloring mechanism is that the content of Fe³⁺and Fe²⁺in the sample glaze decreases with the increase of the amount of silicon powder added.And the glazed surface absorbs light in the ultraviolet region,that is,the increase of ferrous iron ions in the glaze plays a color-increasing effect,so it is cyan;the TG-DSC analysis shows that the glaze firing quality increases after adding silicon powder,indicating The glaze is fired with oxygen in the air.And the main formation temperature of ferrous oxide is 1185?.Under the neutral atmosphere,the exploration of the celadon glaze prepared by the self-reduction method shows that the sufficient oxidation in the initial stage of firing is one of the necessary conditions for obtaining the bright green celadon glaze.Therefore,when silicon powder is used as a reducing agent and a celadon glaze is prepared by a neutral atmosphere from a reduction method,it is necessary to carry out an oxidation stage baking process in the initial stage of firing.