牙科全瓷廢料再利用之研究

牙科領域中，陶瓷因為具有美觀性、高強度以及良好的生物相容性，因此廣泛的受到重視。其中，釔安定氧化鋯(Y-TZP)就因具有耐高溫，熱傳導率低，化學穩定性佳和高破壞韌性，加上有好的生物相容性和機械性質，使其適合於牙科全瓷修復物。近年來，牙科全瓷修復物結合電腦輔助設計/電腦輔助製造(CAD/CAM)技術來取代傳統製造技術。由於色澤更接近自然牙齒、以及加工時間減少，全瓷材料的使用越來越受歡迎。但是，CAD/CAM切削所殘留的廢料，也因為其化學穩定性和耐高溫，不易於作為廢棄物焚化或處置。在本研究中，將牙科氧化鋯全瓷瓷塊(Cercon® )加工後之粉末進行回收，冺用滾筒式和行星式2 種球磨方式，分冸球磨不同時間，評估燒結溫度對回收粉末機械性質的影響。另一方面將回收粉末添加黏結劑（PVA），評估其對切削加工和機械性質的影響。實驗結果顯示：回收粉末的顆粒大小(中位粒徑) D50= 24.7 μm。經過2 種球磨，皆可以產生較細的粉末顆粒，行星式球磨15 分鐘後D50= 4.53 μm，滾筒式球磨9 小時後D50= 8.58 μm。XRD結果顯示，所有回收粉末緻密燒結後皆以正方相(t-ZrO2)存在，而預燒結瓷塊是由單斜相(m-ZrO2)和正方相(t-ZrO2)兩者共存。在機械性質方面，燒結溫度1400 ℃比1300 和1350 ℃，具有較好的機械性能。添加2 %黏結劑的機械性質與加工性比不添加的原始回收粉末來的好。

關鍵字

氧化鋯；球磨；回收粉末

並列摘要

All-ceramic dental restorations are attractive to the dental community because of their aesthetics, higher strength, and excellent biocompatibility. Recently, Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) has been characterized by its high thermal resistance, low thermal conductivity, chemical stability, and high fracture strength. Y-TZP is a high-performance material with excellent biocompatibility and mechanical properties, which render it suitable for restorative dentistry. The combination of Y-TZP ceramics and the CAD/CAM (computer-aided design/computer-aided manufacturing) process has become an increasingly popular alternative to traditional manufacturing techniques. However, the milling dusts and the residual blocks produced in the manufacturing process are environmentally unfriendly. The intrinsic excellent chemical stability and thermal stability do not allow the waste to be incinerated or suitable for normal waste disposal. In this study, the recycled dental all-ceramic (Cercon® ) powder was milled by traditional ball-milling and planetary ball-milling with different duration. Some binder (PVA) was also added to the recycled powder to evaluate its effects on machining and mechanical properties. The results revealed that both these two ball-milling procedures produced finer particle. The particle size (D50) of original recycled powder is 24.7 μm. After planetary ball milling for 15 minutes, the particle size (D50) reduces to 4.53 μm, and 8.58 μm after the traditional ball milling for 9 hours. The XRD results showed that all the sintered recycled powder is tetragonal phase (t-ZrO2), while the pre-sintered blocks are monoclinic (m-ZrO2) and tetragonal (t-ZrO2). Furthermore, the best mechanical properties happened when the recycled powder sintered at 1400℃. Finally, adding 2% PVA binder would promote the machining and mechanical properties.

並列關鍵字

Zirconia ； Recycled powder ； Ball-mill

參考文獻

1.Chevalier,J“What future for zirconia as a biomaterial? Biomaterials,2006 , pp.535-543

8.蔭山健介,加藤寬,大井健司,小林進“Evaluation of Mechanical Properties of Sintered Alumina with Recycling Powder”Journal of the ceramic socirty of society of Japan,1999, pp.482-486

9.Fogagnolo, JB; Ruiz-Navas, EM; Simon, MA; Martinez, MA“Recycling of aluminium alloy and aluminium matrix composite chips by pressing and hot extrusion”Journal of materials processing technology, 143, 2003 , pp.792-795

11.Kojima, T; Mori, Y; Kamiya, M; Sasai, R; Itoh, H “Disintegration process of yttria-stabilized zirconia ceramics using hydrothermal conditions” Journal of materials science,42, 2007, pp.6056-6061

12.Kamiya, M; Mori, Y; Kojima, T; Sasai, R; Itoh, H“Recycling process for yttria-stabilized tetragonal zirconia ceramics using a hydrothermal treatment” Journal of material cycles and waste management, 9, 2007, pp. 27-33

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牙科全瓷廢料再利用之研究

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