本文關(guān)鍵詞：氧化鋯納米陶瓷的制備及其燒結(jié)機(jī)理研究　出處：《湖北工業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 放電等離子燒結(jié)技術(shù) 顆粒重排 晶粒尺寸 最大氣孔尺寸 低溫老化

【摘要】：納米陶瓷是先進(jìn)陶瓷的未來發(fā)展方向。本文選擇3Y-TZP納米陶瓷作為研究對象。材料的微觀結(jié)構(gòu)決定其宏觀性能,因此對材料的化學(xué)組份,微觀結(jié)構(gòu)的設(shè)計(jì)以及燒結(jié)機(jī)制的控制是制備納米陶瓷的關(guān)鍵。Y-TZP材料具有優(yōu)良的力學(xué)性能,在生產(chǎn)生活中被廣泛應(yīng)用。本文綜述了Y-TZP陶瓷的原料及制備工藝、組成優(yōu)化、超塑性和耐磨性的研究進(jìn)展,重點(diǎn)討論了Y-TZP陶瓷在齒科中的應(yīng)用現(xiàn)狀和前景,而Y-TZP陶瓷低溫老化現(xiàn)象限制了它的應(yīng)用。論文總結(jié)了影響Y-TZP陶瓷低溫老化的三個因素,即穩(wěn)定劑的種類與含量、晶粒尺寸的大小以及剩余應(yīng)力的存在,并提出幾種防止低溫老化的措施。制備更加微觀細(xì)化的納米Y-TZP陶瓷是保護(hù)材料不發(fā)生相變的解決方案,對比兩步燒結(jié)法和SPS燒結(jié)法,可知兩步法燒結(jié)中氣孔出現(xiàn)了大尺度的異常生長,而SPS燒結(jié)具有高速升溫、降溫的特點(diǎn),能夠?qū)τ跓Y(jié)過程中晶粒尺寸與燒結(jié)頸部尺寸進(jìn)行掌控;此外,SPS技術(shù)具有更寬的壓力范圍,能夠?qū)崿F(xiàn)燒結(jié)壓力的靈活的調(diào)控。因此,本研究選擇SPS技術(shù)作為燒結(jié)手段開展研究。經(jīng)典“三段式”燒結(jié)理論認(rèn)為:以晶粒作為基本單元的“顆粒重排”主導(dǎo)燒結(jié)初期的密實(shí)化行為,但是對于燒結(jié)的貢獻(xiàn)十分有限,僅限于初期樣品收縮的2%~3%;進(jìn)入燒結(jié)中后期,微觀結(jié)構(gòu)由于擴(kuò)散頸部形成而逐漸“凍結(jié)”導(dǎo)致“顆粒重排”失效,因此燒結(jié)過程僅受到單一原子擴(kuò)散相關(guān)過程主導(dǎo)。基于這一理論,現(xiàn)有陶瓷的制備中往往強(qiáng)調(diào)原子擴(kuò)散相關(guān)行為對于燒結(jié)過程的作用,而對于“顆粒重排”相關(guān)過程并未引起足夠的重視。經(jīng)典理論的建立是基于傳統(tǒng)粗晶陶瓷材料的燒結(jié),但是隨著納米材料的迅速發(fā)展,其中的一些局限性也逐漸顯現(xiàn)。本論文將對3Y-TZP納米陶瓷在SPS燒結(jié)過程中的“顆粒重排”行為進(jìn)行探索研究。通過模具設(shè)計(jì),對SPS燒結(jié)過程中電場、升溫速率、壓力等因素進(jìn)行逐一分離,在燒結(jié)行為表征中,同時引入相對密度、晶粒尺寸與“最大氣孔尺寸”的綜合考量。通過研究工藝參數(shù)對顆粒重排行為的影響,對納米陶瓷燒結(jié)過程中異于傳統(tǒng)理論的顆粒重排行為的動力學(xué)成因進(jìn)行解釋,探究“顆粒重排”在納米陶瓷燒結(jié)中有效作用階段與相關(guān)作用,進(jìn)一步對3Y-TZP納米陶瓷低溫老化性能展開研究。
[Abstract]:Nano-ceramics are the future development direction of advanced ceramics. In this paper, 3Y-TZP nano-ceramics are chosen as the research object. The microstructure of the materials determines their macroscopic properties, so the chemical components of the materials are determined. The design of microstructure and the control of sintering mechanism are the key to the preparation of nano-ceramics. Y-TZP materials have excellent mechanical properties. Y-TZP ceramics are widely used in production and life. In this paper, the research progress of Y-TZP ceramics, such as raw materials, preparation process, composition optimization, superplasticity and wear resistance, is reviewed. The application status and prospect of Y-TZP ceramics in dentistry were discussed in detail. The application of Y-TZP ceramics is limited by the phenomenon of low temperature aging. This paper summarizes the three factors that affect the low temperature aging of Y-TZP ceramics, that is, the types and contents of stabilizers. The existence of grain size and residual stress, and some measures to prevent low temperature aging are put forward. It is a solution to protect the material from phase transformation by preparing more micro-fine Y-TZP ceramics. Compared with the two-step sintering and SPS sintering, it can be seen that there are large scale abnormal growth of pores in two-step sintering, while SPS sintering has the characteristics of high-speed heating and cooling. Can control the grain size and the size of the sintering neck during the sintering process; In addition, SPS technology has a wider pressure range, which can realize the flexible control of sintering pressure. In this study, SPS technology was chosen as the sintering method. The classical "three-stage" sintering theory holds that the "particle rearrangement" with grain as the basic unit dominates the densification behavior in the initial stage of sintering. However, the contribution to sintering is very limited, which is limited to 2 / 3 of the initial sample shrinkage. In the middle and late stage of sintering, the microstructure is gradually "frozen" due to the formation of diffusion neck, which leads to the failure of "particle rearrangement", so the sintering process is only dominated by the single atom diffusion related process. The effect of atomic diffusion behavior on sintering process is often emphasized in the preparation of existing ceramics. The classical theory is based on the sintering of traditional coarse grained ceramic materials, but with the rapid development of nanomaterials. In this paper, the "particle rearrangement" behavior of 3Y-TZP nanocrystalline ceramics during SPS sintering is studied. The electric field, heating rate and pressure during SPS sintering were separated one by one, and the relative density was introduced in the sintering behavior characterization. The effect of process parameters on particle rearrangement behavior was studied by considering the grain size and "maximum pore size". The dynamic causes of particle rearrangement in the sintering process of nanocrystalline ceramics were explained, and the effective stages and related effects of particle rearrangement in the sintering process of nano-ceramics were explored. The low temperature aging properties of 3Y-TZP nanoceramics were further studied.
【學(xué)位授予單位】：湖北工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TQ174.1

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