- 學位論文
二莫耳百分比之釔安定氧化鋯奈米粉末的性質研究
Study of the Properties of 2 mol% Y2O3-Stabilized ZrO2 Nano-powders
摘要
研究目的： 陶瓷熔和金屬牙冠應用在牙科裡已經有許多年了，但因為其薄蓋冠為金屬材質，所以使用在前牙區其美觀會是一項缺點，而生物相容性也是一項問題，因此全陶瓷冠的發展在臨床應用上是很重要的。近幾年常用的氧化鋯陶瓷材料已被用來加強改善一般陶瓷材料的不足與脆性的缺點，而應用在牙科上也只有十幾年的時間。 在1970年代，氧化鋯的相變韌化被發現，爾後有許多的研究指出證明這項機制使其機械性質都要比傳統的陶瓷來得好，因傳統的陶瓷只能限於固定式局部假牙前牙區的單顆假牙或最多到3單位的牙冠牙橋。而氧化鋯極佳的機械性質則可以應用於後牙區的復形物，且可以降低薄蓋冠的厚度。而因為氧化鋯的相變韌化是由正方晶相轉變為單斜晶相而得，要使正方晶相存在於室溫，就必須加入穩定劑才行，而牙科材料常用的穩定劑為氧化釔。因此本研究是要合成釔安定氧化鋯粉末，觀察其基本性質。 研究方法： 利用氯氧化鋯和硝酸釔為原料，加入酒精-水比為5：1的混合溶液中，經計算使所得氧化釔的量要在2 mol％，再加入分散劑後，將混合溶液放入75℃恆溫水浴槽中攪拌，得到膠狀的沉澱物後，再加入氨水溶液，使pH值為7，再攪拌一段時間後過濾，產物必須使用去離子水沖洗，而後放入烘箱以得氧化鋯粉末，並利用熱差分析、富立葉轉換紅外線光譜分析、X-光繞射分析、掃瞄式和穿透式電子顯微、熱膨脹儀、維氏硬度分析粉末的基本性質。 結果： 1.熱差分析中在274℃和439℃時有兩個放熱峰，經JCPDS卡比對得到在274℃時為氯化氨的形成，且正方晶相形成溫度為439℃。X-光繞射分析所得的氧化鋯晶相大多為正方晶相，且合成的晶粒大小約為11nm。 2.自製粉末製成試片之維氏硬度和密度均較市售粉末試片稍弱。 結論： 1.利用氨水滴定加入混合溶液中，會產生氯化氨殘留在產物內，而沒有被去離子水沖洗乾淨且被包覆在氧化鋯內，當煆燒溫度達到500℃氧化鋯之正方晶相出現之後，氯化氨也就汽化掉了。 2.經修正實驗後，在濾液中加入硝酸銀看是否有無氯化銀沈澱產生，以確定所得產物有洗淨。 3.自製粉末之燒結體比市售粉末之燒結體的維氏硬度較弱，且密度也較小，因自製粉末之燒結體有較多的孔洞，緻密性不佳，且有裂痕產生。
並列摘要
Porcelain-fused-to-metal(PFM) crowns have been used in dentistry for several years，but the inner metal framework is a disadvantage as used in the esthetic area. The risk of biological incompatibility is also a problem, so the development of all-ceramic crowns is of importance in clinical. The zirconia ceramic has been used in dental material for more than ten years to improve the disadvantage of the conventional ceramic. The transformation toughening capability of zirconia is discovered in the mid-1970s. There are many research that have been carried out to prove this mechanism and the mechanical property is better than the conventional ceramic that can only be used to replace anterior teeth with single crown restorations or maximum with three units fixed partial dentures. The strength of zirconia is capable to be applied in the posterior fixed partial dentures with a reduction in core thickness. The transformation toughening capability is the mechanism that transforms from tetragonal to monoclinic crystal structure. Alloying pure zirconia with stabilizing oxides can retain the tetragonal structure at room temperature. The most used stabilizer in dental material is Y2O3. The purpose of this study was to synthesize the powder and observe its property. Zirconia chloride octal-hydrate(ZrOCl2˙8H20) and yttrium nitrate [Y(NO3)3˙6H2O] were used as the starting material and then were dissolved in the deionized water-ethanol solution in a volume ratio of 1：5 Y2O3 to (Y2O3+ZrO2) ratio was 2 mol％，and polyethylenglycol(PEG) was added into the solution as a dispersant. The mixture solution was stirred and heated to 75℃ in a thermostatic bath to obtain the gel-like precipitates. NH4OH was added into the gel until pH= 7 and then was stirred for a period of time. After filtration，the gel was rinsed with deionized water. Then put the gel in the oven to obtain the YSZ powder. DTA、XRD、FTIR、SEM、TEM、TMA、Vickers hardness test were used to identify the property of YSZ powder. The results of the experiments were shown below： 1. According to the DTA，there were 2 exothermal peaks at 274℃ and 439℃ found. According to the JCPDS card，the NH4Cl is formed at 274℃，and the tetragonal-forming temperature of the pH=7 YSZ powder is 439℃. The YSZ powder crystographic was almost tetragonal and the grain size was about 11 nm in XRD analysis. 2. The Vickers hardness of the sample made of the Tosoh powder (TZ-3Y-E) was a little better than that made of the synthesized powder. The conclusion was shown below： 1. The NH4OH was added into the mixed solution to obtain the YSZ precipitates，but also the NH4Cl was formed. The precipitates did not be rinsed clearly，and the NH4Cl still remained in the precipitates. When the powder was sintered at 500℃，the NH4Cl was vaporized. 2. After revising the experiment，AgNO3 was added into the filter to confirm the purification of the gel. 3. There were pores，crack lines and poor density observed in the synthesized sintered-body compared with the Tosoh sintered-body in the SEM field.