本文選題：石墨烯 + 氧化鋯��； 參考：《蘇州大學(xué)》2015年碩士論文

【摘要】：氧化鋯陶瓷材料具有十分優(yōu)異測(cè)化學(xué)、物理性能。其在室溫下具有較好的力學(xué)性能,而且其抗高溫、耐化學(xué)腐蝕性較好,是一種非常有應(yīng)用前景的高溫陶瓷。然而,由于陶瓷自身的本征脆性及其本征脆性導(dǎo)致的較差的摩擦磨損性能,很大程度制約了其更廣泛的應(yīng)用。針對(duì)上述問題,發(fā)展氧化鋯陶瓷復(fù)合材料被公認(rèn)為是一種行之有效的方法。本論文基于多層石墨烯納米片(GNS)優(yōu)異的力學(xué)性能,提出了石墨烯納米片增韌5mol.%氧化釔穩(wěn)定氧化鋯(TZP)復(fù)合材料的研究思路。為確保復(fù)合材料中GNS的均勻分布,采用了超聲混合結(jié)合表面活性劑分散的方法制得了GNS/TZP復(fù)合材料粉末(其中,GNS的含量分別為0wt.%,0.5wt.%,0.75wt.%和1.0wt.%),利用放電等離子燒結(jié)(spark plasma sintering,SPS)技術(shù)制備GNS/TZP復(fù)合材料,并對(duì)所制備的樣品進(jìn)行了物相表征,顯微組織結(jié)構(gòu)分析及相關(guān)力學(xué)性能如彈性模量、顯微硬度、斷裂韌性及摩擦磨損性能評(píng)價(jià)。采用X射線衍射和拉曼光譜進(jìn)一步研究了放電等離子(SPS)燒結(jié)復(fù)合材料的物相組成,結(jié)果表明TZP在高溫?zé)Y(jié)中沒有相變,依然保持其四方晶體結(jié)構(gòu),并且GNS在高溫高壓燒結(jié)條件下可保持其固有結(jié)構(gòu)。通過冷場(chǎng)發(fā)射掃描電鏡(SEM),對(duì)材料顯微組織/形貌觀察發(fā)現(xiàn),GNS在復(fù)合材料中分布較為均勻,且復(fù)合材料中晶粒得到了顯著細(xì)化,這主要得益于石墨烯納米片優(yōu)異的傳熱性能。使用儀器化微納壓入設(shè)備和顯微硬度計(jì)測(cè)試研究了氧化鋯及GNS/TZP復(fù)合材料的力學(xué)性能(如顯微硬度、彈性模量和斷裂韌性),并使用儀器化劃入技術(shù)研究了復(fù)合材料的摩擦莫尋在材料表面進(jìn)行劃入實(shí)驗(yàn),得出劃入殘余深度和TZP在不同GNS添加量下的摩擦系數(shù)。使用SEM觀察材料斷面,壓痕、劃痕形貌和壓入、劃入產(chǎn)生的裂紋形貌。再由以上結(jié)果分析復(fù)合材料的增韌機(jī)制和摩擦磨損性能。研究結(jié)果表明,與未添加GNSs的TZP相比,0.5wt%GNS/TZP彈性模量較TZP提升了~20%,顯微硬度增加了~12%,斷裂韌性提高了~36%(從4.1MPa m0.5提升到5.6MPa m0.5).。研究發(fā)現(xiàn)GNS/TZP復(fù)合材料主要增韌機(jī)制是石墨烯的拔出,橋接,裂紋的偏轉(zhuǎn)和裂紋的分叉。采用已有模型計(jì)算了復(fù)合材料界面在應(yīng)力,并得出了GNS的臨界增韌長度。計(jì)算了GNS的拔出應(yīng)力釋放率和復(fù)合材料的殘余熱應(yīng)力,結(jié)果表明殘余熱應(yīng)力對(duì)于復(fù)合材料的力學(xué)性能影響可以忽略。儀器化劃入測(cè)試結(jié)果表明,盡管GNS/TZP復(fù)合材料的摩擦系數(shù)高于TZP,但純TZP材料在儀器化劃入過程中的損傷機(jī)制主要表現(xiàn)為脆性斷裂,而GNS/TZP復(fù)合材料則轉(zhuǎn)變?yōu)檎持p為主、脆性斷裂為輔的損傷機(jī)制,這主要源于GNS/TZP復(fù)合材料斷裂韌性的顯著改善。
[Abstract]:Zirconia ceramic materials have excellent chemical and physical properties. It has good mechanical properties at room temperature, and its resistance to high temperature and chemical corrosion is better. It is a kind of high temperature ceramics with great application prospect. However, due to the intrinsic brittleness of ceramics and the poor friction and wear properties due to the intrinsic brittleness, its wider application is restricted to a great extent. To solve the above problems, the development of zirconia ceramic composites is recognized as an effective method. Based on the excellent mechanical properties of multilayer graphene nanocrystalline (GNS), a new method for the study of 5 mol.% yttrium oxide stabilized zirconia (TZP) composite toughened by graphene nanocrystalline was proposed in this paper. To ensure the uniform distribution of GNS in composites, GNS/TZP composite powder was prepared by ultrasonic mixing combined with surfactant dispersion method. The content of GNS/TZP composite powder was 0 wt. 0. 5 wt.g. 0. 75 wt.% and 1. 0 wt. respectively. Spark plasma sintering (Spark plasma interingling) was used to prepare GNS/TZP composite. The microstructure and mechanical properties such as modulus of elasticity, microhardness, fracture toughness and friction and wear properties of the samples were analyzed. The phase composition of SPS sintered composites was further studied by X-ray diffraction and Raman spectroscopy. The results showed that TZP had no phase transition during high temperature sintering and maintained its tetragonal crystal structure. And GNS can keep its inherent structure under high temperature and high pressure sintering condition. By means of cold field emission scanning electron microscopy (SEM), the microstructure / morphology of the composites was observed. It was found that the GNS distributed uniformly in the composites, and the grains in the composites were significantly refined, which was mainly due to the excellent heat transfer properties of graphene nanoparticles. The mechanical properties (such as microhardness) of zirconia and GNS/TZP composites were studied by instrumentation and microhardness tester. The elastic modulus and fracture toughness of the composites were studied by means of instrumented scratch technique. The friction coefficient of TZP and the residual depth of scratching on the surface of the composite were obtained. SEM was used to observe the fracture profile, indentation, scratch morphology and crack morphology caused by indentation and indentation. Then, the toughening mechanism and friction and wear properties of the composites were analyzed based on the above results. The results show that compared with TZP without GNSs, the elastic modulus of 0.5 w / t GNS / TZP is 20% higher than that of TZP, the microhardness is increased by 12%, and the fracture toughness is increased by 36% (from 4.1MPa m 0.5 to 5.6MPa m 0.5 路). It is found that the main toughening mechanisms of GNS/TZP composites are the drawing of graphene, bridging, crack deflection and crack bifurcation. The stress at the interface of the composite is calculated by using the existing model, and the critical toughening length of GNS is obtained. The pull-out stress release rate of GNS and the residual thermal stress of the composite are calculated. The results show that the influence of residual thermal stress on the mechanical properties of the composite can be neglected. The results of instrumentation scratch test show that although the friction coefficient of GNS/TZP composite is higher than that of TZP, the damage mechanism of pure TZP material during instrumentation is mainly brittle fracture, while that of GNS/TZP composite is mainly adhesive wear. The damage mechanism of brittle fracture is mainly due to the remarkable improvement of fracture toughness of GNS/TZP composites.
【學(xué)位授予單位】：蘇州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB332

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本文編號(hào)：1882898