Coating Poly Methyl Methacrylate or Polyvinyl Alcohol on Alumina Powder with Spray Drying

• Main Authors: Shi-Jiun Lin, 林溪浚
• Other Authors: 湯華興
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/dq988p

碩士 === 國立臺北科技大學 === 機電整合研究所 === 98 === In the rapid prototyping process of Ceramic Laser Sintering, coated-powder was produced by hot air drying with ball mill. Slurry was dried to obtain alumina blocks, ant then the coated-powder was collected with the method of ball mill. In hot air drying, the larger the alumina block is, the lower the efficiency is in ball mill. The purpose of this paper is to coat polyvinyl alcohol (PVA) or poly methyl methacrylate(PMMA) on the surface of the alumina powder by spray drying and ball mill. Spray drying with ball mill can obtain smaller coated-powder than that obtained by hot air drying with ball mill, and can increase the production rate. The property of coated- powder was also studied for future works. On coated-powder production process, spray drying with ball mill was better than that of hot air drying with ball mill. The efficiency of the former was 3 to 4 times than the latter’s. The result of experiment of slurry dispersion revealed slurry added with PVA or PMMA could achieve a better dispersion in pH10; however, the worse dispersion was obtained in pH4. The result of experiment of particle size analysis revealed the particle size distribution of the powder coated PVA or PMMA by spray drying is concentrated in 10μm. After ball milling, the average particle size is 0.653μm in PVA and 0.69μm in PMMA. The result of experiment of burning out revealed the coating rate was 3.272% and 3.337% for the powder coated with PVA and PMMA respectively. The result of experiment of viscosity revealed, both processes obtained the best dispersion in pH10. The flexural strengths of the specimens fabricated by the powder coated with PVA or PMMA was 430Mpa and 421Mpa respectively.