快速烧结制备纳米Y-TZP材料

研究了快速热压烧结和放电等离子快速烧结（ＳＰＳ）制备纳米Ｙ－ＴＺＰ材料,利用快速热压烧结和ＳＰＳ快速烧结,可在烧结温度为１２００℃,保温９￣１０ｍｉｎ条件下,制得相对密度超过９９％的Ｙ－ＴＺＰ材料,研究发现,虽然快速热压烧结和ＳＰＳ烧结都可使Ｙ－ＴＺＰ在相同温度下的密度高于普通热压烧结,但两种快速烧结所得Ｙ－ＴＺＰ的晶粒孝大于无压烧结所得;另外,快速热压结所得样品的结构不够均匀,而ＳＰＳ烧结样品的     

纳米Y-TZP材料烧结过程晶粒生长的分析

分析了无压烧结,热压烧结等ＳＰＳ烧结过程中晶粒生长的行为及表观活化能。结果表明：在１１００￣１３００℃之间,纳米Ｙ－ＴＺＰ材料在以上几种烧结条件下的晶粒生长行为不同。无压烧结时晶粒生长较慢,而热压烧结和ＳＰＳ烧结时晶粒生长较快。对晶粒生长的活化能分析可在一定程度上解释以上现象。分析结果显示：无压烧结的表观活化能为２８１ｋＪ／ｍｏｌ。与纳米Ｙ－ＴＺＰ材料的晶界扩散活化能相近;热压烧结过程中,由于外压     

Y—PSZ对Al2O3纳米粉烧结特性及性能的影响

在Ａｌ２Ｏ３纳米粉中加入１００－４００ｍｇ．ｇ＾－１的０．０２５ｍｏｌＹ２Ｏ２（Ｙ－ＰＳＺ），探讨了加入量对Ａｌ２Ｏ３纳米粉的烧结特性和烧成陶瓷力学性能的影响，结果表明，Ｙ－ＰＳＺ可促进烧结致密化，降低烧结温度，并且有效地抑制烧结时Ａｌ２Ｏ３晶粒的长大，提高烧成陶瓷的性能。     

Y2O3含量及制备工艺参数对Y—TZP纳米粉烧结体性能的影响

用化学共沉淀法制备了Ｙ２Ｏ３含量不同的两种Ｙ－ＴＺＰ纳米粉体；采用了不同压力不冷等静压成形制备素坯；研究了Ｙ２Ｏ３含量，素坯成型压力及烧结温度对Ｙ－ＴＺＰ陶瓷体密度，组织结构及机械性能的影响。     

Y_2O_3含量及制备工艺参数对Y－TZP纳米粉烧结体性能的影响

用化学共沉淀法制备了Ｙ２Ｏ３含量不同的两种Ｙ－ＴＺＰ纳米粉体；采用不同压力下冷等静压成形制备素坯；研究Ｙ２Ｏ３含量、素坯成型压力及烧结温度对Ｙ－ＴＺＰ陶瓷体密度、组织结构及机械性能的影响。     

ZrO2（Y2O3）纳米粉在超高压下快速烧结

研究了超高压（５ＧＰａ）、高温（１３５０℃）下烧结的ＺｒＯ２（Ｙ２Ｏ３）纳米材料的结构及相关系。结果表明：水解法制备的纳米（９ｎｍ）２．２Ｙ－ＺｒＯ２粉体经超高压烧结１０ｓ，致密度即达９９．５％以上，晶粒迅速长大达６０ｎｍ。在０￣９９ｓ范围内，随烧结时间延长，２．２Ｙ－ＴＺＰ的ｔ相增加，四方度（ｃ·ａ＾－１）减小，表明Ｙ２Ｏ３固溶进入ＺｒＯ２晶格内。     

热压烧结制备纳米Y-TZP材料

本文研究了热攻结制备纳米Ｙ－ＴＺＰ材料的过程,研究结果表明：热压结纳米前一些新的特点,主要是纳米Ｙ－ＴＺＰ材料在热压烧结时,由于软团聚未能有效地破碎。造成烧结过程中团聚体内部首先致密化,珉在体之间产生张力,导致裂纹状大气孔的出现,同时因石墨模具的限制,热压时的外压不足以克服塑性滑移产生所需的“阈值”,因此大气孔无法“压碎”,使产地密度比相同温度下无压结还低,针对热压烧结纳米Ｙ－ＴＺＰ材料的局限性。     

LCMAS微晶玻璃／Y—TZP复相材料

本工作对ＬＣＭＡＳ微晶玻璃／Ｙ－ＴＺＰ复相材料在不同的烧结温度下所出现的晶相进行了研究，发现材料在烧结温度下，Ｙ－ＴＺＰ中的ＺｒＯ２与微晶玻璃中的ＳｉＯ２发生化学反应生成锆英石（ＺｒＯ２·ＳｉＯ２），少量Ｙ－ＴＺＰ的加入起不到相变增韧作用。由于Ｙ－ＴＺＰ起到微晶玻璃晶核剂的作用，仍能使材料的抗折强度和断裂韧性得到大幅度的提高。当Ｙ－ＴＺＰ含量为９５ｗｔ％时，复相材料的抗折强度和断裂韧性分别为６３１     

添加Al_2O_3对SiC板粒／Y－TZP复合材料力学性能的影响

本文以ＳｉＣ板粒、ＺｒＯＣｌ２－８Ｈ２Ｏ、ＡｌＣｌ３和Ｙ（ＭＯ）３为原料，利用共沉淀和热压烧结工艺，制备ＳｉＣ板粒／Ｙ－ＴＺＰ和（含Ａｌ２Ｏ３）ＳｉＣ板粒／Ｙ－ＴＺＰ复合材料．测试了材料的室温和高温力学性能．研究了添加Ａｌ２Ｏ３对ＳｉＣ板粒／Ｙ－ＴＺＯ复合材料的影响．结果表明，ＳｉＣ板粒／Ｙ－ＴＺＰ复合材料与Ｙ－ＴＺＰ陶瓷相比，其室温强度和韧性出现明显下降，高温强度也没有改善；而在ＳｉＣ板粒与Ｙ－ＴＺＰ复合的基础上，添加Ａｌ２Ｏ３可明显提高材料的强度和断裂韧性，同时，材料的高温强度也获得显著改善．     

添加Al2O3对SiC板粒／Y—TZP复合材料力学性能的影响

本以ＳｉＣ板粒、ＺｒＯＣｌ２·８Ｈ２Ｏ、ＡｌＣｌ３和Ｙ（ＭＯ）３为原料，利用共沉淀和热压烧结工艺，制备ＳｉＣ板粒／Ｙ－ＴＺＰ和（含Ａｌ２Ｏ３）ＳｉＣ板粒／Ｙ－ＴＺＰ复合材料。测试了材料的室温和高温力学性能。研究了添加Ａｌ２Ｏ３对ＳｉＣ板粒／Ｙ－ＴＺＯ复合材料的影响。结果表明，ＳｉＣ板粒／Ｙ－ＴＺＰ复合材料与Ｙ－ＴＺＰ复合材料与Ｙ－ＴＺＰ陶瓷相比，其室温强度和韧性出现明显下降，高温强度也没有改善；     

Effects of sintering conditions on the microstructure and mechanical properties of SiC prepared using powders recovered from kerf loss sludge

The effects of sintering conditions on the microstructure and mechanical properties of the sintered SiC prepared using the SiC powder recovered from the kerf loss sludge were investigated. The recovered SiC powders were consolidated by spark plasma sintering (SPS) and conventional sintering methods. The effects of sintering temperature, time and methods (SPS and conventional sintering) on the phase, grain size and density of SiC were systematically studied. The Vickers hardness of spark plasma-sintered (SPSed) samples was higher than that of conventional sintered samples due to small grain size. When holding time was increased from 10 to 30 min, the grain size and relative density of SPSed samples were also increased, which lead to the almost constant Vickers hardness by competing effects of grain size and relative density. When holding time was over 30 min, no appreciable change of the relative density and grain size were observed, which can lead to similar values of Vickers hardness. SPS process can be used to make SiC with high density and hardness at relatively low temperature compared with the conventional sintering process.     

Thermal and mechanical properties of uranium nitride prepared by SPS technique

Nitride fuel is a promising nuclear fuel in fast breeder reactor (FBR) or accelerator-driven subcritical reactor (ADSR) system. In this study, high-density UN pellets were prepared by Spark plasma sintering (SPS) technique. The sample density strongly depended on the sintering temperature and pressure, and the pellets with 90% of theoretical density were easily obtained with low sintering temperature and short sintering time without any milling process. The grain size and pore size were much smaller compared with those for samples prepared by conventional sintering process. Despite of the small grain size, the thermal conductivity remains the high value. The SPS process permits easy densification of nitrides without any deterioration of thermal and mechanical properties, considered to be suitable as a preparation method of nitride fuels.     

Microwave sintering of zirconia ceramics

The potential of a microwave heating technique for the sintering of 3Y-TZP ceramics is demonstrated. High density samples were obtained by short duration firing in a domestic microwave oven. The ultrafine and monomodal size distribution of grains resulting from the process has important implications in terms of mechanical properties. The hardness and fracture toughness values compare very well with long duration, conventionally fired 3Y-TZP ceramics.     

Spark plasma sintering on nanometer scale WC–Co powder

Nanometer scale WC–11Co powder was sintered by spark plasma sintering (SPS) process in order to improve the properties of the cemented carbides. Properties such as density and hardness were measured. The microstructures of sintered WC–11Co cemented carbides were observed. The grain size of WC in alloys was also obtained. The results showed that spark plasma sintering could lower the sintering temperature, increased the density and circumscribed the growth of grain size of WC. Besides, the hardness of the sintered cemented alloys that was dependent on the grain size and densification could also be improved by SPS. SPS was an effective method to get WC–11Co cemented carbides with fine grain size and good properties.     

制备工艺对n型Bi_2Te_3基材料热电性能和抗压强度的影响

以商用区熔(ZM)n型Bi2Te3基材料为原料,采用简单研磨结合放电等离子烧结技术(ZM+SPS)和熔体旋甩(MS)结合放电等离子烧结技术(MS+SPS)制备了n型Bi2Te3基块体热电材料.对三种不同工艺制备出样品的微结构、热电性能和力学性能进行了研究.FESEM微结构表征结果表明:区熔样品的晶粒粗大,有较强的取向性;经SPS烧结后,晶粒细化,取向性大为降低;而区熔样品经MS+SPS后,晶粒得到进一步细化,且没有明显的取向性.对三组样品进行的热电性能和抗压强度测试,结果表明:区熔原料最大ZT值为0.72(430K),抗压强度仅为40MPa;经SPS后,样品的最大ZT值为0.68(440K),抗压强度为110MPa,相比区熔样品提高了175%;MS+SPS样品的最大ZT值为0.96(320K),其室温ZT值相比区熔样品提高了64%,抗压强度相比区熔样品提高了400%,达到200MPa.     

Comparisons of grain size-density trajectory during spark plasma sintering and hot-pressing of zirconia

Spark plasma sintering (SPS) and hot-pressing (HP) of a granulated stabilized zirconia powder have been investigated for a fixed macroscopic compaction pressure of 100 MPa and a fixed heating rate (25 °C/min for HP, 50 °C/min for SPS). The “relative density/grain size” trajectories have been established for both sintering methods.HP is shown to be similar to SPS for the manufacturing of polycrystalline TZ3Y materials with a final grain size well below the micrometer. Independently of the sintering technology employed, it is interesting to note that three kinds of microstructures are obtained depending on the experimental parameters: porous materials (opened porosity, relative density between 61 and 90%) with a nanometer grain size (around 75-80 nm), dense materials (closed porosity, relative density between 90 and 98%) with a nanometer grain size (around 75-80 nm), fully dense material with a submicron grain size (around 160 nm using SPS and around 105 nm using HP).     

田口法研究3Y-TZP/TiN导电陶瓷材料最佳化制程

实验用田口法研究了添加30wt%氮化钛的钇稳定氧化锆基陶瓷材料(3Y-TZP/TiN)制造工艺.选择烧结方式、TiN粉末振荡时间、第一阶段保温时间及第二阶段烧结温度四个工艺参数作为控制因子,设计L9正交表进行实验规划.烧结后,检测试片断裂韧性、抗弯强度、硬度、相对密度及电阻值.最后通过变异数分析找出最佳参数,再进行实验验证.本研究得到的最佳化烧结工艺为:TiN粉末振动8 h,采用两步烧结法,第一阶段烧结温度1450℃,不保温,第二阶段烧结温度1150℃,保温20 h.结果显示,采用该工艺得到了抗弯强度平均值为736.75 MPa、断裂韧性为7.545 MPa.m1/2的氧化锆基导电陶瓷材料.研究发现,第一阶段保温时间对断裂韧性的影响程度最大,其次依次为烧结方式、TiN粒径大小及第二阶段保温温度.断裂韧性的微结构影响因子为四方相与单斜相数量的比值,当此值达到最高时,断裂韧性也达到最高值为9.275 MPa.m1/2.另外,添加30wt%TiN的氧化锆电阻率平均值为3.26 m.cm,可以进行电火花加工.     

超高压成型制备Y-TZP纳米陶瓷

研究了用超高压成型制备Ｙ－ＴＺＰ纳米陶瓷的方法,通过采用新的成型方法。在５０００吨六面顶压机上实现了高达３ＧＰａ的超高压成型,获得相对密度达６０％的３ｍｏｌＹ２Ｏ３－ＺｒＯ２陶瓷素坯,比在４５０ＭＰａ下冷等静压成型所得素坯的密度高出１３％,这种超高压成型所得素坯具有极佳的烧结性能,可在１０５０～１１００℃下经无压烧结至密化,研究表明,这种素坯烧结性低,有利于制备ＺｒＯ２晶粒尺寸〈１００ｎｍ的纳米陶