摘要
采用粒度级配技术及低钠硅溶胶制备了熔模铸造面层涂料。利用激光粒度仪测试了涂料中粉料粒度及硅溶胶中胶粒粒度分布,使用pH计、分析天平和粘度计等测试了随时间变化的硅溶胶pH值、SiO_(2)含量及涂料粘度值。采用透射电镜观察了原始硅溶胶及胶凝硅溶胶胶粒形貌。结果表明:涂料使用初期,随涂料中水分减少,涂料清液pH值降低、SiO_(2)含量及涂料粘度增加;涂料使用后期,含水量明显减少,涂料中硅溶胶胶粒接触几率增加,胶粒间的布朗运动导致胶粒聚集并长大成团,最终导致涂料清液pH值急剧降低,SiO_(2)含量急剧增高,涂料粘度显著增大并使涂层厚度明显变厚,面层有裂纹产生。
The surface layer coating of investment casting was prepared by particle size distribution technology and silica sol with low sodium ions.The powder particle sizes and colloidal particle sizes of the silica sol were tested via a laser particle size analyser.The pH values of the silica sol,SiO_(2) contents of the silica sol and viscosity values of the coating were tested by a pH meter,an analytical balance and a viscometer,respectively.The colloidal particle morphologies of the original silica sol and gelatinized silica sol were observed via transmission electron microscopy(TEM).The results show that,with decreasing of water content in the coating,the pH value of the clear solution of coating decreases,and the SiO_(2) content and viscosity value of the coating increase during the early stage of coating applying.During the later stage of coating applying,the decreasing of water content is obvious,resulting in the increase of the contacting probabilities of the silica sol colloidal particles in the coating,and the aggregation and growth of colloidal particles caused by the Brownian motion between the colloidal particles,finally leading to rapid decrease of the pH value of the clear solution of the coating,rapid increase of the SiO_(2) content,obviously increasing of the coating viscosity value which resulting in the increase of the thickness of coating layer and the generation of cracks on the surface layer coating.
作者
伍林
姜卫国
郝悦
胡玉昆
张琼元
赵代银
曾洪
郭维华
WU Lin;JIANG Wei-guo;HAO Yue;HU Yu-kun;ZHANG Qiong-yuan;ZHAO Dai-yin;ZENGHong;GUO Wei-hua(State Key Laboratory of Clean and Efficient Turbomachinery Power Equipment,Deyang 618000,Sichuan,China;Dongfang Electric Corporation Dongfang Turbine Co.,Ltd.,Deyang 618000,Sichuan,China;School of Intelligent Manufacturing,Weifang University of Science and Technology,Shouguang 262700,Shandong,China)
出处
《铸造》
2025年第7期967-974,共8页
Foundry
基金
“清洁高效透平动力装备全国重点实验室开放课题资助”(DEC8300CG202408837A1228026)
山东省自然科学基金项目(ZR2022ME066)。
关键词
熔模铸造
硅溶胶
涂料
PH值
粘度
胶凝机理
investment casting
silica sol
coating
pH value
viscosity
gelation mechanism
