含中孔和微孔的多孔炭的孔结构表征

采用低温氮气吸附法表征了由硬模板法制备的含微孔和无序中孔、由软模板法制备的含微孔和贯通中孔的偏氯乙烯聚合物(PVDC)基多孔炭的孔隙结构,计算了比表面积、孔径分布、孔体积和平均孔径等孔隙结构参数。结果表明:氮气吸附法分析结果与电子显微镜结果一致,碳化物含一定量的微孔和中孔,含中孔和微孔多孔炭的比表面积小于PVDC直接碳化得到的微孔炭,但孔容远大于PVDC基微孔炭;使用NLDFT模型计算得到硬模板制备的多孔炭比表面积为1 669m2/g,孔容为2.07cm3/g,中孔孔径约18nm,与电镜观察结果相同。由软模板法制备的多孔炭比表面积为1 267m2/g,中孔孔径25nm,小于观察到的实际孔径,这可能由于吸附点在大孔部分较少而影响了拟合精度所致。     

烧结316L不锈钢粉末多孔材料的K_(IC)性能研究

以316L不锈钢粉末为原料,采用模压成形与烧结工艺,制备出孔隙度为20%～45%的烧结316L不锈钢粉末多孔材料,分别采用了1 150℃和1 200℃烧结温度.研究了烧结温度、孔隙度对烧结316L不锈钢粉末多孔材料的断裂韧度的影响.结果表明:断裂韧度随孔隙度的升高呈下降趋势,但断裂韧度与孔隙度是一种非单调的函数关系.表面裂纹总是沿着烧结颗粒边缘、孔隙等结构薄弱环节扩展.     

多孔生物玻璃陶瓷的生物相容性研究

通过制备模拟体液来模拟人体环境对制备的多孔生物活性陶瓷进行生物相容性测试,将模拟体系温度、pH分别控制在36．5±1．5℃、7．3±1．5。将制备的多孔生物陶瓷浸泡在1．0倍与1．5倍的模拟体液中,分别培养2,4,6d。通过SEM观察培养之后多孔陶瓷材料的表面发现：培养生物玻璃多孔材料生长的羟基磷灰石状况良好,随着在模拟体液中生长时间的增加,生物玻璃矿化产生羟基磷灰石含量剧增以及磷灰石形貌发生变化。培养2d磷灰石在材料表面以及多孔内部延伸,羟基磷灰石生长尺寸可达到20μm,随时间延长玻璃表面生长出尺寸为10—100μm的树枝状结构磷灰石,培养6d有形状规则的片状磷灰石生成,尺寸达到100μm以上。     

多孔玻璃制备技术创新实验研究

随着多孔玻璃在临床医药及医药品、石油工业、民用生产等的广泛应用,多孔玻璃制备技术的研究也显得越来越重要。介绍了多孔玻璃的用途、制备工艺、热处理对多孔玻璃微孔孔径的影响。学生在创新实验过程中,了解了多孔玻璃制备技术及用途,提高了创新意识和动手能力,增强了团队合作精神。     

烧结316L不锈钢粉末多孔材料压缩性能的研究

以316L不锈钢粉末为原料,采用模压成形与烧结工艺,制备出孔隙度为20%~45%的烧结316L不锈钢粉末多孔材料,分别采用1 150℃和1 200℃烧结温度.烧结316L不锈钢粉末多孔材料的压缩应力-应变曲线上第二区域和第三区域分界不明显.相同烧结温度下,烧结316L不锈钢粉末多孔材料的压缩屈服强度、压缩弹性模量随孔隙度的升高呈指数下降趋势.     

钛表面制备多孔氧化物陶瓷层的实验设计

为提高生物医用金属钛材料表面的生物活性和生物相容性,以乙酸钙、β-甘油磷酸钠混合溶液作为电解液,采用微弧氧化实验方法,在金属钛表面制备出具有多孔结构的氧化物陶瓷层。用X射线衍射仪(XRD)、扫描电子显微镜(SEM)以及能谱分析仪(EDS)对氧化物陶瓷层的组成及结构进行了分析。结果表明:氧化物陶瓷层的主晶相为锐钛矿型二氧化钛,同时含有钛、金红石型二氧化钛以及钛酸钙相;试样表面形成大量的微孔,孔径1～3μm,孔洞分布均匀;电解液中的Ca、P元素也参与了反应,并沉积在氧化物陶瓷层内。通过此实验方法可以有效提高金属钛的生物活性和生物相容性。     

透气钢的制备方法及其在塑料模具中的应用研究

本文通过粉末粒度分级和控制粉末压制力获得具有适当孔隙率的金属粉末生坯,烧结之后获得具有连通微孔隙可以透气的粉末冶金多孔材料;向材料中渗入液体之后进行气体透过试验,气体可以顺利从材料中穿过,说明材料内部的孔隙是连通的;金相照片和SEM照片从微观上进一步证实了这种连通性;而注塑实验表明粘性的塑料并不会进入材料内的微孔隙中堵塞气体通道,注塑过程可以重复地进行;制备获得的粉末冶金多孔材料强度介于200～250MPa,可以满足透气模具钢的使用要求.     

微孔玻璃在鱼塘养殖中的应用研究

本实验以DM308玻璃粉作为原料制备微孔玻璃片,研究采用加入添加剂、改变玻璃粉目数以及改变热处理工艺来获取强度、孔径、孔隙率等综合性能较好的微孔玻璃片,然后将玻璃片运用到鱼塘中利用微孔来为养殖输送氧气。本实验主要分成两大部分:一是用烧结法制备硬度较好、孔隙率高、导气性优良的微孔玻璃片,二是设计并制作一个小型鱼缸,模拟微孔玻璃片为鱼塘增氧的过程。     

Zeolites模板法制备氮掺杂多孔碳材料及其CO_2吸附性能

以吡咯为碳源和氮源,分子筛为模板剂,通过模板法制备了氮掺杂多孔碳材料(NPCs),研究了碳源与模板剂质量比对NPCs的孔隙结构、氮元素含量及其对CO_2吸附性能的影响。采用全自动气体吸附仪、扫描电镜、透射电镜及X光射线电子能谱分析仪对NPCs的孔隙结构、形貌及元素组成进行了表征,并在常温常压下采用静态吸附法对CO_2吸附性能进行了测试。结果表明:当碳源与模板剂质量配比为0.5时,所制备NPCs的比表面积为660 m~2/g,平均孔径为536 nm,总孔容为0.883 cm~3/g,微孔孔容达0.130 cm~3/g,微孔包含的超微孔所占比例更大,对CO_2有最高吸附量84.26 mg/g(298 K,0.1 MPa)。     

铜尾矿微晶玻璃的制备及其性能研究

微晶玻璃是一种新型绿色环保建筑装饰材料,利用尾矿制备微晶玻璃可以使工业矿渣得到有效利用。以Cr_2O_3为晶核剂,研究了不同烧结温度对铜尾矿制备微晶玻璃性能的影响,并对试样的密度、莫氏硬度、抗压强度以及耐腐蚀性进行测试。结果表明:烧结后试样的密度、抗压强度、以及莫氏硬度的变化趋势都是随着温度的上升,先增大后减小;试样的耐酸碱性随着烧结温度的上升,也先增大后减小,当烧结温度为1100℃时,各项性能最优。     

利用废陶瓷辊棒制备堇青石陶瓷材料

利用废陶瓷辊棒作为主要原料采用高温煅烧法制备堇青石陶瓷材料,研究了烧成工艺对堇青石材料的晶相、显微结构和性能的影响。利用X射线衍射仪表征试样的晶相结构;利用扫描电子显微镜观察试样的显微结构;利用排水法测试试样的显气孔率和体积密度;通过万能试验机检测试样的抗弯强度。研究结果表明:试样经煅烧后形成堇青石陶瓷材料,主晶相为堇青石相,次晶相为镁铝尖晶石相。堇青石呈粒状分布,试样中具有一定量的玻璃相,均匀地分布着微米级的微孔。随着煅烧温度和保温时间的增加,显气孔率先减小后增大,体积密度先增大后减小,抗弯强度先增大后减小,最佳烧结工艺为煅烧温度1 350℃保温时间3h时,显气孔率最小为21 %,体积密度为1.96 g/cm³,抗弯强度最大为58 MPa。     

陶瓷靶材的制备及性能表征

以ZnO、Al2O3粉体为原料,采用常压烧结方法制备高导电性Al:ZnO(AZO)陶瓷靶材,并系统研究了不同的成型压力、烧结工艺及其烧结温度对靶材电学特性和密度的影响。结果表明:成型压力的大小对于ZAO靶材本身的密度、成品率及最后烧结的性能都有很大的影响。成型压力为14Mpa时,靶材的电阻率最小,为0.35Ωcm。烧结温度的选择也是制备靶材的关键,为了避免靶材出现断层、上表面壳曲、微裂纹甚至开裂现象,要采用缓慢升温,长时间保温与缓慢降温的方法。实验表明,在1250℃时,AZO靶材表面平整致密,基本上达到了陶瓷靶材的烧结终点。     

Low temperature sintering and performance of aluminum nitride/borosilicate glass

Aluminum nitride （AlN）/borosilicate glass composites were prepared by the tape casting process and hot-press sintered at 950 ℃ with AIN and SiO2-B203-ZnO-Al2O3-Li2O glass as starting materials. We characterized and analyzed the variation of the microstructure, bulk density, porosity, dielectric constant, thermal conductivity and thermal expansion coefficient （TEC） of the ceramic samples as a function of AIN content. Results show that AIN and SiO2-B2O3-ZnO-Al2O3-Li2O glass can be sintered at 950 ℃, and ZnAI204 and Zn2SiO4 phase precipitated to form glass-ceramic. The performance of the ceramic samples was determined by the composition and bulk density of the composites. Lower AlN content was found redounding to liquid phase sintering, and higher bulk density of composites can be accordingly obtained. With the increase of porosity, corresponding decreases were located in the dielectric constant, thermal conductivity and TEC of the ceramic samples. When the mass fraction of AlN was 40%, the ceramic samples possessed a low dielectric constant （4.5-5.0）, high thermal conductivity （11.6 W/（m.K）） and a proper TEC （3.0× 10^-6 K^-1 which matched that of silicon）. The excellent performance makes this kind of low temperature co-fired ceramic a promising candidate for application in the micro-electronics packaging industry.     

AlN-ZrO_2复相材料的烧结与热稳定性探讨

以稳定ZrO2粉和金属Al粉为原料,试验制备了在N2气氛和不同烧成温度条件下以AlN为结合相的AlN-ZrO2复相材料。初步探讨了影响AlN-ZrO2复相材料常温抗折强度和抗热震性能的因素。实验发现:与P-ZrO2材料相比,AlN-ZrO2复相材料更难于烧结,抗热震性能明显提高;引入添加剂SrCO3可改善AlN-ZrO2复相材料烧结性能,但随着烧成温度的提高,其试样热震后的残余强度稍有损失。试用金属Al粉用量8%,以SrCO3为添加剂,控制N2气体流量0.12~0.14L/min的条件下,经1 400℃×3 h烧成的试样抗热震性能优良,5次热震后的残余强度为5.61 MPa。     

Sintering and microstructure of silicon carbide ceramic with Y3Al5O12 added by sol-gel method

Silicon carbide (SIC) ceramic with YAG (Y3Al5O12) additive added by sol-gel method was liquid-phase sintered at different sintering temperatures, and the sintering mechanism and microstructural characteristics of resulting silicon carbide ceramics were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and elemental distribution of surface (EDS). YAG (yttrium aluminum garnet) phase formed before the sintering and its uniform distribution in the SiC/YAG composite powder decreased the sintering temperature and improved the densification of SiC ceramic. The suitable sintering temperature was 1860 ℃ with the specimen sintered at this temperature having superior sintering and mechanical properties, smaller crystal size and fewer microstructure defects. Three characteristics of improved toughness of SiC ceramic with YAG added by sol-gel method were microstructural densification, main-crack deflection and crystal ‘bridging‘.     

Synthesis of Ag（Nb0.8Ta0.2）O3 Ceramics Under Different Ambient Conditions

Different ambient conditions for the synthesis of Ag（Nb0.8Ta0.2）O3 ceramics were investi- gated. The Ag（Nb0.8Ta0.2）O3 powder was synthesized at 950 ℃ under different ambient conditions, and then pressed into disks and sintered between 1060 ℃ and 1100 ℃ respectively. Samples were investigated by X-ray diffraction, scanning electron microscopy and dielectric measurement. The results show that perovskite Ag（Nb0.8Ta0.2）O3 powder was easier to be synthesized in air than in vacuum at 950℃. Grain size of ceramic samples sintered in air was uniform （about 1 μm） and its dielectric loss was small for its high density. However, the samples decomposed greatly and ceramics could hardly be densified when sintered in vacuum, Thus,. higher atmospheric pressure and oxygen atmosphere would benifit the synthesis of Ag （Nb0.8Ta0.2）O3, and suppress its decomposition at high temperature.     

烧结温度对WC-16TiC-4TaC-9Co硬质合金微观组织与性能的影响

选用WC、（W,Ti）C、TaC和Co粉配制WC-16TiC-4TaC-9Co合金混合料,经球磨后压制压坯,在1 410℃、1 430℃和1 450℃温度下真空烧结.测试烧结试样的性能,采用扫描电子显微镜（SEM）观察其微观形貌.结果表明：随着烧结温度升高,合金晶粒尺寸明显长大.1 450℃真空烧结的试样综合性能较好,WC平均尺寸为0.7μm,（W,Ti,Ta）C平均尺寸为3μm.     

Effect of temperature on the hydration process and strength development in blends of Portland cement and activated coal gangue or fly ash

This paper describes the results of an investigation into the effect of the variation of curing temperatures between 0 and 60 °C on the hydration process, pore structure variation, and compressive strength development of activated coal gangue-cement blend (ACGC). Hardened ACGC pastes cured for hydration periods from 1 to 360 d were examined using the non-evaporable water method, thermal analysis, mercury intrusion porosimetry, and mechanical testing. To evaluate the specific effect of activated coal gangue (ACG) as a supplementary cementing material (SCM), a fly ash-cement blend (FAC) was used as a control. Results show that raising the curing temperature accelerates pozzolanic reactions involving the SCMs, increasing the degree of hydration of the cement blends, and hence increasing the rate of improvement in strength. The effect of curing temperature on FAC is greater than that on ACGC. The pore structure of the hardened cement paste is improved by increasing the curing temperature up to 40 °C, but when the curing temperature reaches 60 °C, the changing nature of the pore structure leads to a decrease in strength. The correlation between compressive strength and the degree of hydration and porosity is linear in nature.     

NiO薄膜制备及电催化性能测试教学实验设计

该文针对目前含尿素废水高温水解处理的成本和能耗问题,进行了NiO薄膜制备及电催化分解尿素的综合性教学实验设计。通过控制条件采用水热法,在导电玻璃FTO基底上生长了多孔道网络微结构NiO薄膜,研究了水热时间、煅烧温度、添加表面活性剂等制备条件对NiO薄膜电催化分解尿素性能的影响。对NiO薄膜进行XRD、XPS、SEM、TEM等组成、形貌表征,以及CV、LSV、Tafel曲线、EIS等电化学测试,结果表明:在最优水热12 h,300℃煅烧,添加结构导向剂EDTA条件下,制备的NiO薄膜电极与现有文献报道的镍泡沫电极材料相比,尿素电催化分解起始电位由0.60 V降低为0.36 V。