O2/Ar气体流量比对射频磁控溅射HfO2薄膜的影响

采用射频磁控溅射法,以HfO2陶瓷作为靶材,在石英衬底上制备了HfO2薄膜.通过椭圆偏振光谱仪(SE)、X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)研究了不同O2/Ar气体流量比对薄膜沉积速率、结构、形貌等的影响.结果表明,随着O2/Ar气体流量比从0增加到0.50,薄膜的沉积速率逐渐下降.O2/Ar气体...     

负载型中孔SiO2-Fe2O3膜的制备与表征

将模板技术和溶胶凝胶法相结合,制备SiO2/K-M复合陶瓷膜管负载型SiO2-Fe2O3膜.采用XRD、SEMI、R、氮吸附和气体渗透性能测试等手段对该膜材料的表面形貌、结构、孔径分布和气体渗透性能进行表征,并探讨了制膜条件对成膜情况的影响.结果表明:SiO2-Fe2O3膜成膜情况良好,过渡层SiO2与SiO2-Fe2O3膜结合紧密;在SiO2-Fe2O3膜中,Fe2O3和SiO2都是以晶体形式存在,Fe2O3已进入SiO2骨架内部,与SiO2发生键合,形成Si-O-Fe结构;Fe2O3-SiO2膜孔径分布集中于4 nm,气体的渗透属于Knudsen扩散控制区;Fe2O3-SiO2膜对HCl/N2和HCl/C2H4的分离因子分别达到2.55和1.81.     

V2O5薄膜在传感器上的研究进展

V2O5薄膜具有优异的物理、化学性质,在化工催化、电子、电化学等许多领域有广泛的应用,由于V2O5薄膜对还原性气体和湿度具有良好的敏感特性,其在气体和湿度传感器上的研究也日渐广泛,因此本文综述了V2O5为基体的薄膜在气体传感器和湿度传感器上的研究进展及存在的问题和解决的思路.     

γ-Fe2O3响应苯类气体敏感材料特性研究

从电导控制理论,对掺钇、硫酸根离子等多元化、微结构γ-Fe2O3的热稳定性、响应苯类气体敏感性及其对相邻气体的高选择性,进行了系统研究与机理分析,并用DTA、TEM、RQ-1等方法进行表征与测量.结果表明,掺入适量Y2O3后能使γ-Fe2O3的相变温度提高到618℃,从而改善γ-Fe2O3基气敏元件的热稳定性;硫酸根离子和金离子的适量掺杂有助于提高苯类气体的敏感特性;γ-Fe2O3基体材料的微细化可增强γ-Fe2O3的表面气敏特性.从而为苯类有机气体敏感元件研制提供了一条新途径.     

Sm2O3掺杂Bi2O3-ZnO-Nb2O5基陶瓷的结构与性能

研究了Sm2O3掺杂的bi2O3-ZnO-Nb2O5(BZN)基陶瓷(Bi1.5-xSmxZn0.5)(Zn0.5Nb1.5)O7(O≤x≤0.6,BSZN),的结构及介电性能.结果表明纯BZN陶瓷的结构为立方焦绿石单相;当Sm2O3掺杂量较少(O＜x≤0.5)时,样品的相结构仍然保持立方焦绿石单相;随着Sm2O3掺杂量的进一步增加(x≥0.6),样品出现其它相.同时,试样的介电性能随结构的变化而呈现有规律的变化.     

氧化亚氮(N2O)标准气体复现性及性能评价的研究(续)

论述了温室气体监测用N2O标准气体气相色谱分析方法和条件,并对该标准气体配制的均匀性、稳定性及随压力变化的实验结果进行了分析与考察,对该气体标准物质的性能进行了评价.     

In2O3的掺杂及气敏性能研究

较为详尽地论述了n型半导体材料In2O3的掺杂情况,并就不同金属氧化物掺杂引起的气敏性能作了简单的分析,发现不同的金属氧化物掺杂对NO2、O3及一些还原性气体的灵敏度有不同程度的提高,改善了In2O3的气敏性能,同时还探讨了In2O3对不同气体(H2、H2S、NO2、O3,Cl2、C2H5OH)的敏感机理.     

MgO-Al2O3-SiO2-TiO2-Y2O3玻璃的弹性模量

根据硬盘基板用材料的要求,制备了MgO-A12Oa-SiO2-TiO2-Y2Oa高弹性模量玻璃(120GPa).玻璃的弹性模量随组成的变化服从Makishima-Mackenzie理论,MgO、A12O3、TiO2、Y2O3等具有较高单位体积离解能的氧化物有利于提高玻璃的弹性模量.但玻璃弹性模量的理论计算值低于测试值.这是因为Makishima-Mackenzie理论没有考虑玻璃内阳离子的具体配位状态,对MgO、Y2O3堆积密度因子的推导存在误差.因此利用Makishima-Mackenzie理论发展高弹性模量玻璃时应对MgO、Y2O3等氧化物的计算进行修正.     

氧化亚氮(N_2O)标准气体复现性及性能评价的研究

论述了温室气体监测用N2O标准气体气相色谱分析方法和条件,并对该标准气体配制的均匀性、稳定性及随压力变化的实验结果进行了分析与考察,对该气体标准物质的性能进行了评价。     

氧化亚氮(N2O)标准气体复现性及性能评价的研究

论述了温室气体监测用N2O标准气体气相色谱分析方法和条件,并对该标准气体配制的均匀性、稳定性及随压力变化的实验结果进行了分析与考察,对该气体标准物质的性能进行了评价。     

Emission characteristics of coal combustion in different O2/N2, O2/CO2 and O2/RFG atmosphere

This study investigates the emission characteristics of CO(2), SO(2) and NOx in the flue gas of coal combustion by varying the compositions and concentrations of feed gas (O(2)/CO(2)/N(2)) and the ratios of recycled flue gas. The differences between O(2)/recycled flue gas (O(2)/RFG) combustion and general air combustion are also discussed. Experimental results indicate that the maximum concentration of CO(2) in O(2)/CO(2) combustion system is 95% as the feed gas is 30% O(2)/70% CO(2). The average concentration of CO(2) in the flue gas of O(2)/CO(2) coal combustion system is higher than 90% and much higher than that of O(2)/N(2) coal combustion system. This high concentration of CO(2) is beneficial for the separation of CO(2) from the flue gas by adsorption or absorption technologies. The maximum concentration of CO(2) in O(2)/N(2) combustion system is only 34% at the feed gas 50% O(2)/50% N(2), the concentration of CO(2) is increased with the concentration of O(2) in feed gas. By O(2)/CO(2) combustion technology, higher concentration of SO(2) is produced as the feed gas is 30% O(2)/70% CO(2) or 40% O(2)/60% CO(2), while higher concentration of NOx is produced as the feed gas is 20% O(2)/80% CO(2) or 50% O(2)/50% CO(2). The mass flow rates of CO(2), SO(2) and NOx in the flue gas are all increased with the ratio of recycled flue gas except for the feed gas 20% O(2)/80% CO(2). The enhanced mass flow rates of air pollutants in such O(2)/RFG combustion system are also beneficial for improving the control efficiencies of air pollution control devices. By O(2)/N(2) combustion technology, higher concentrations of SO(2) and NOx are produced as the feed gas is 21% O(2)/79% N(2). The results also indicate that the formation of NOx in general air combustion system is higher than that in O(2)/RFG or O(2)/CO(2) combustion system.     

大气等离子喷涂工艺参数对Al2O3涂层性能的影响

为了提高燃烧器工艺烧嘴的使用寿命,在UMCo-50基材表面大气等离子喷涂Al2O3层。采用正交试验法对喷涂工艺参数进行了优化,运用微观形貌分析、X射线衍射分析并结合强度及显微硬度等测试方法,系统研究了喷涂主气流量、功率和送粉量对AI2O3涂层综合性能的影响规律。结果表明:喷涂主气流量、功率和送粉量对Al2O3涂层性能具有交互性影响,在40L/min Ar,48 kW和30g/min条件下可以获得性能较好的Al2O3涂层,极大地提高了UMCo-50基材的抗高温氧化和耐磨性能,使之具有广阔的应用前景。     

Highly sensitive and selective trimethylamine sensor using one-dimensional ZnO-Cr2O3 hetero-nanostructures

Highly selective and sensitive detection of trimethylamine (TMA) was achieved by the decoration of discrete p-type Cr(2)O(3) nanoparticles on n-type ZnO nanowire (NW) networks. Semielliptical Cr(2)O(3) nanoparticles with lateral widths of 3-8 nm were deposited on ZnO NWs by the thermal evaporation of CrCl(2) at 630 °C, while a continuous Cr(2)O(3) shell layer with a thickness of 30-40 nm was uniformly coated on ZnO NWs at 670 °C. The response (R(a)/R(g): R(a), resistance in air; R(g), resistance in gas) to 5 ppm TMA of Cr(2)O(3)-decorated ZnO NWs was 17.8 at 400 °C, which was 2.4 times higher than that to 5 ppm C(2)H(5)OH and 4.3-8.4 times higher than those to 5 ppm p-xylene, NH(3), benzene, C(3)H(8), toluene, CO, and H(2). In contrast, both pristine ZnO and ZnO (core)-Cr(2)O(3) (shell) nanocables (NCs) showed comparable responses to the different gases. The highly selective and sensitive detection of TMA that was achieved by the deposition of semielliptical Cr(2)O(3) nanoparticles on ZnO NW networks was explained by the catalytic effect of Cr(2)O(3) and the extension of the electron depletion layer via the formation of p-n junctions.     

中空纤维担载Al2O3-SiO2复合膜的研制

采用溶胶-凝胶法在α-Al2O3中空纤维载体上制备了Al2O3-SiO2复合膜,并对复合膜的制备条件及稳定性进行了研究.利用SEM和EDS对复合膜的微观形貌及化学组成进行了分析.结果表明,所制备的担载复合膜表面完整、无缺陷.气体渗透实验进一步说明,复合膜具有一定的气体选择性,在0.1 MPa下对H2/N2的分离因子为3.03,表明气体通过膜的扩散以Knuen扩散传质为主.用等温氮气吸附实验测定了非担载膜的孔径大小和分布,其比表面积为294.85 m2/g,总孔容为0.28 mL/g,最可几孔径小于3 nm.     

中空纤维担载Al_2O_3-SiO_2复合膜的研制

采用溶胶-凝胶法在α-Al2O3中空纤维载体上制备了Al2O3-SiO2复合膜,并对复合膜的制备条件及稳定性进行了研究.利用SEM和EDS对复合膜的微观形貌及化学组成进行了分析.结果表明,所制备的担载复合膜表面完整、无缺陷.气体渗透实验进一步说明,复合膜具有一定的气体选择性,在0.1 MPa下对H2/N2的分离因子为3.03,表明气体通过膜的扩散以Knuen扩散传质为主.用等温氮气吸附实验测定了非担载膜的孔径大小和分布,其比表面积为294.85 m2/g,总孔容为0.28 mL/g,最可几孔径小于3 nm.     

Cr_2O_3对氧化钙陶瓷烧结过程的影响

研究Cr2O3添加剂对氧化钙陶瓷烧结性能的影响。结果表明:Cr2O3能促进氧化钙陶瓷烧结密度和抗水化性能的提高,并且随着添加剂含量的增加,陶瓷抗水化性能不断提高;提高烧结温度,能提高陶瓷密度和抗水化性能;在烧结过程中,生成的CaCr2O4为液相,连结CaO晶粒,促进陶瓷烧结,增大了陶瓷的烧结密度,CaCr2O4包裹在CaO晶粒表面,能大幅度提高陶瓷抗水化性能。     

Quantitative absorption spectroscopy of residual water vapor in high-purity gases: pressure broadening of the 1.39253-microm H2O transition by N2, HCl, HBr, Cl2, and O2

We determined the respective pressure-broadening coefficients of HCl, HBr, Cl2, and O2 (expressed relative to that of the reference gas N2) for the (v1,v2,v3)J(Ka,Kc) = (0,0,0)3(0,3) --> (1,0,1)2(0,2) rovibrational transition of H2 16O that occurs at 1.39253 microm. The experiment used a continuous-wave cavity ring-down spectroscopy analyzer to measure the peak absorption losses as a function of added moisture concentration. The measured pressure-broadening coefficients for HCl, HBr, Cl2, and O2 are, respectively, 2.76, 2.48, 1.39, and 0.49 times that of the N2 pressure-broadening coefficient, and detection limits for water vapor range from 0.22 nmol mol(-1) for O2 matrix gas to 2.3 nmol mol(-1) for HBr matrix gas. The degradation of the detection limit (relative to the N2 matrix gas) is ascribed to a pressure-broadening-induced reduction in peak absorption cross section and to elevated background loss from the matrix gas.     

Rare-earth La2O3 modification of laser-clad coatings

The effect of rare-earth La2O3 on laser-clad coatings has been studied. For this purpose, nickel-based alloy powders with different contents of La2O3 were laser-clad on to a steel substrate. The clad coatings were examined and tested for microstructural features, microhardness, inclusions and phase composition. The results are compared with those for coatings without La2O3. The comparison indicates that additions of La2O3 refine the microstructure of the clad, and the coating increases its microhardness. Moreover, the wear resistance and corrosion resistance of the clad coatings are also enhanced.     

Study of x/spl alpha/-Fe/sub 2/O/sub 3/-(1-x)ZrO/sub 2/ solid solution for low-temperature resistive oxygen gas sensors

A noble type of oxygen-sensitive and electrical-conductive material, ZrO/sub 2/-based with /spl alpha/-Fe/sub 2/O/sub 3/ thick-film gas sensor, was investigated for low operating temperature. Amorphous-like solid solutions of x/spl alpha/-Fe/sub 2/O/sub 3/-(1-x)ZrO/sub 2/ powders were derived using the high-energy ball milling technique, and their physical and microstructural properties were characterized from DTA, XRD, TEM, and XPS. The oxygen gas-sensing properties of the screen-printed thick-film gas sensors fabricated from such mechanically-alloyed materials were characterized systematically. Very good sensing properties were obtained with a relative resistance value of 82 in 20% oxygen, and at a low operating temperature of 320/spl deg/C. AC impedance spectra and thermally stimulated current were characterized to investigate the conduction properties of the solid solution, 0.2/spl alpha/-Fe/sub 2/O/sub 3/-0.8ZrO/sub 2/, in air and nitrogen (carrier gas), respectively. It was found that the Arrhenius plots of /spl sigma/T versus 1000/T have two distinct gradients corresponding to two activation energies in the high and low temperature regions. The transition temperature occurs at about 320/spl deg/C that corresponds to an optimal operating temperature of the gas sensor. It is believed that the high oxygen vacancy concentration present in the solid solution, 0.2/spl alpha/-Fe/sub 2/O/sub 3/-0.8ZrO/sub 2/, and the dissociation of the associated oxygen vacancy defect complexes at 320/spl deg/C are the critical factors for the high relative resistance to oxygen gas at low operating temperature.     

Al_2O_3－MgAl_2O_4陶瓷的试验研究

在Ａｌ＿２Ｏ＿３中添加５－１５ｗｔ％ＭｇＡｌ＿２Ｏ＿４，采用热压注法制备Ａｌ＿２Ｏ＿３－ＭｇＡｌ＿２Ｏ４陶瓷。研究表明，Ａｌ＿２Ｏ＿３－ＭｇＡｌ＿２Ｏ＿４陶瓷具有良好的高温电阻率和抗熔渣－种子的腐蚀能力，经过进一步改进可望作为燃煤ＭＨＤ发电通道（半热壁型）阳极区电极间绝缘片材料。