共查询到19条相似文献,搜索用时 62 毫秒
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熔体自生原位增韧Al2O3/20%ZrO2(3Y)复合陶瓷显微结构、裂纹扩展与增韧 总被引:2,自引:2,他引:2
通过在铝热剂中添加一定含量的微米ZrO2(3Y)粉末,以铝热燃烧、陶瓷/金属液相分离与熔体自生方式,制备出以t-ZrO2纳微米纤维镶嵌于其上且具有不同结构取向的蓝宝石棒晶为基的Al2O3/20%ZrO2(3Y)复合陶瓷,并结合力学性能测试,研究材料显微结构、裂纹扩展与增韧之间的内在联系.研究得出,陶瓷抗弯强度与断裂韧性分别达到1 086MPa与11.6 MPa·m05;存在于蓝宝石棒晶上大量、细密的低能异相界面(相界面间距为纳微米尺度)及高的残余压应力,使蓝宝石棒晶得以补强;具有高强度、高模量且长径比为6.0~8.0的蓝宝石棒晶及分布于其上的高残余压应力又迫使裂纹沿棒晶边界扩展,诱发裂纹偏转、棒晶桥接与拔出增韧机制,并相继伴随着t-ZrO2相变、α-Al2O3片晶桥接、Cr颗粒延性相塑变及相变诱发微裂纹多重增韧机制的协同作用,保证材料在保持高强度的同时,又具有高韧性与高的缺陷容忍性. 相似文献
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基于国外定向凝固氧化物/氧化物共晶复合陶瓷的晶体生长动力学行为的研究成果,阐述其动力学机制,分析动力学因素对微观结构形态的影响,探讨晶体生长热力学、动力学行为与微观结构形态之间的关系,同时结合以燃烧合成、快速凝固技术制备的新型高强韧Al2O3/ZrO2(Y2O3)共晶复合陶瓷,探讨共晶复合陶瓷在快速凝固条件下的晶体生长动力学行为.结合定向凝固与快速凝固两种晶体生长机制,得知过冷度、凝固界面前沿的温度梯度是影响晶体生长方式的重要因素,且受二者决定的凝固速率(即晶体生长速率)则决定材料的最终微观结构与形态. 相似文献
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本文利用超音速火焰喷涂技术(HVOF),在20G钢表面制备了掺杂1wt.%、3wt.%、5wt.%三种不同含量Y2O3的NiCr-Cr3C2金属陶瓷复合涂层,并探究了其在650℃,Na2SO4/K2SO4熔盐环境中的热腐蚀性能。利用扫描电镜(SEM)、显微硬度计、拉伸试验机等对涂层的微观结构和力学性能进行了表征,利用X射线衍射仪(XRD)、拉曼光谱、X射线能谱仪(EDS)对复合涂层热腐蚀产物形貌、物相进行分析。结果表明掺杂1wt.%Y2O3的NiCr-Cr3C2复合涂层结构致密、孔隙率低、结合强度高,显微硬度达到801HV。热腐蚀过程中掺杂Y2O3的NiCr-Cr3C2复合涂层表面均生成耐蚀性良好且致密的Cr2O3膜。随着Y2O3掺杂量的增加,涂层的耐热腐蚀性能先升高后下降,当Y2O3掺杂量为1wt.%时,复合涂层表现出最佳的耐热腐蚀性能。 相似文献
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以电熔刚玉、天然石墨以及利用碳热还原法合成的ZrO2-SiC复合粉体为原料制备了Al2O3-C质耐火材料,研究了ZrO2-SiC复合粉体加入量对Al2O3-C质耐火材料抗热震性能的影响.结果表明:添加质量分数为4%的ZrO2-SiC复合粉体试样的显气孔率最低为18.8%;添加6%ZrO2-SiC复合粉体的试样,在1 200 ℃的温度下热震次数达到10次后,其表面并未出现明显裂纹,且其残余耐压强度为16.71 MPa,耐压强度保持率为40.9%,具有良好的抗热震性能. 相似文献
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(ZrO2)0.96(Y2O3)0.03(Al2O3)0.01陶瓷的制备及性能研究 总被引:1,自引:0,他引:1
采用化学共沉淀法制备(ZrO2)0.96(Y2O3)0.03(Al2O3)0.01的粉末, 在不同的升温速率、不同的烧结时间和不同的烧结温度等烧结工艺下制备出(ZrO2)0.96(Y2O3)0.03(Al2O3)0.01三相体系复合陶瓷. 经研究发现, 在升温速率和降温速率均为5 ℃·min^-1 的烧结制度下, 1550 ℃烧结时, 可以得到抗弯强度达998 MPa, 抗热震次数达33次, 相对密度达96%和电性能较好的烧结体. 相似文献
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在铝热剂中引入不同量ZrO2(3Y)微米粉末,以燃烧合成技术,制备出A12O3/10%、17%、21%、27%、33%ZrO2(3Y)系列成分自生复合陶瓷棒材.XRD分析与SEM观察显示:具有亚共晶成分的陶瓷熔体因以离异共晶方式生长,使得凝固后的陶瓷基体主要由α-A12O3片晶、t-ZrO2枝晶或块晶组成;而随ZrO2(3Y)添加量的增多,陶瓷晶体生长方式又由离异共晶向共生共晶生长发生转化,共晶棒晶体积分数增多,使得A12O3/33%ZrO2(3Y)的陶瓷基体以微米、亚微米t-ZrO2纤维镶嵌其上的A12O3共晶棒晶和少量α-A12O3片晶构成.经力学性能测试,系列陶瓷棒材的硬度与断裂韧度随ZrO2(3Y)添加量增多而逐渐升高,陶瓷棒材硬度最高值达15.7GPa,断裂韧度最高可达10MPa·m1/2. 相似文献
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The content of zirconia has a remarkable influerce on transformation behavior and mechanical properties of Al2O3/ZrO2 (2Y) composites. When 15% and 20% ZrO2(2Y) was added to Al2O3, the bending strength and fracture of the content of ZrO2 (2Y) on transformation and mechanical properties was investigated. The changes of m-ZrO2 and t-ZrO2 phases content before and after fracture were measured by X-ray diffraction quantitative phase analysis, It is shown that improvement in bending strength and fracture toughness of the Al2O3/ ZrO2 (2Y) composites is due to the phase transformation toughening mechanism of ZrO2 (2Y) and thermal expansion mismatch. 相似文献
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通过对几种不同掺杂量的钼钇烧结坯(经同种工艺烧结)显微组织、密度、硬度性能的分析与讨论,研究了氧化钇对钼烧结的推迟作用以及不同含量氧化钇对钼坯密度、硬度的影响规律。 相似文献
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YAG:1% (atom fraction) Yb3 , 0.5% (atom fraction) Er3 transparent ceramics were fabricated by the solid state reaction method using high-purity Y2O3, Al2O3, Yb2O3, and Er2O3 powders as starting materials. The mixed powder compact was sintered at 1760 ℃ for 6 h in vacuum and annealed at 1500 ℃ for 10 h in an air atmosphere. The ceramics consisted of about 10 μm grains and exhibited a pore-free structure. The optical transmittance of the ceramics at 1064 nm was nearly 80%. Upconversion emissions were investigated on the ceramics pumped by a 980 nm continuous wave diode laser, and strong green emission centered at 523 and 559 nm and red emission centered at 669 nm were observed, which originated from the radiative transitions of 2H11/2→4I15/2, 4S3/2→4I15/2, and 4F9/2→4I15/2 of Er3 ions, respectively. 相似文献
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Liu Rushi Chi Liangshang 《中国稀土学报(英文版)》2005,23(5):568-568
Red emitting phosphor (BaCa)3 (PO4)2 : Ce, Mn was prepared by solid state reactions. Effect of chemical component, preparation conditions on the performance of the phosphor was studied by using TGDTG, XRD and phosphor relative brightness meter. It is found that the host ( Bax Ca1-x ) 3 (PO4) 2 is present as a distorted Ca3(PO4)2 structure. Ce^3+ acts as a sensitiser, and Mn^2+ is activator. By energy transfer from Ce^3+ to Mn^2+, Mn^2+ is activated and emits red light with wavelength around 650 nm. The phosphor powder shows the highest emitting brightness, when the con- centrations of Ce^3+and Mn^2+ are both at 0.15 mol. 相似文献
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(Bi2O3)0.73(Y2O3)0.27 fine powders prepared by wet chemical precipitation method were cold isostatically pressed to form solid electrolyte tubes, and sintered at 900 ℃ for 10 h in the air. Their pumping oxygen characteristics in non-dehydrated Ar gas were investigated, where a ZrO2 (Y2O3 stabilized) oxygen sensor was used to measure the oxygen partial pressure Po2. The results showed that the Po2 value reached magnitudes of 1×10-20-1×10-10 Pa at the applied pumping oxygen voltage of 0.5 V, 1×10-37-1×10-27 Pa at 1.0 V and 1×10-53-1×10-47 Pa at 2.0 V within the temperature range from 550 to 650 ℃. Moreover, no cracks were found in the tested solid electrolyte tubes. Thus, the Bi2O3-Y2O3 system might be used in solid electrolyte oxygen pump for purifying gases. 相似文献
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Oxidationofmetalsoralloysathightemperatures canbetreatedasaspecialcaseofmetalliccorrosion,inwhichsolidphasesinteracteitherwithaliquid agentoragaseousagent.Toimprovetheresistance againsthigh temperatureoxidationandelectrochemical corrosionofmetals,thesurfa… 相似文献