共查询到20条相似文献,搜索用时 65 毫秒
1.
使用RAMAN光谱和DTA方法研究了含少量Na+和Ti4+的CaO-Al2O3-SiO2系玻璃,发现在纯CAS系玻璃(Ca/Al≥1/2,Al/Si≤1)中,Al3+仅有一部分进入玻璃网络,少量Na+的引入,有助于Al3+进一步进入玻璃网络中,Na+起了间接补强玻璃网络的作用,Na+和Ca2+离子对Al3+进入玻璃网络结构程度的影响可认为是Na+和Ca2+离子分别以[AlO4]Na和[AlO4]Ca[AlO4]基团的形式进入玻璃网络中,由于结合几率和体积效应,使[AlO4]Na较[AlO4]Ca[AlO4]更易进入玻璃网络中。Ti4+以[TiO4]的形式进入玻璃网络,它对Al3+是否能进入玻璃网络无明显影响。Na+和Ti4+的单独引入,均能使玻璃网络的聚合程度增强,析晶活化能提高;而当Na+和Ti4+同时引入时,玻璃网络聚合程度和纯CAS系玻璃相差不大,析晶活化能有所降低。少量Na+的引入,不会影响析出主晶相的种类和数量,而Ti4+的引入,则会影响到所析出主晶相的种类和数量。 相似文献
2.
通过差热分析曲线和物相分析等研究了4Al+3TO_2+3C普通化学反应和自燃烧化学反应的特点。研究结果表明,在一定的升温速率下Al、TiO_2、C相互之间均能发生相互化学反应;随着升温速率的提高,Al、TiO_2、C任意两组元之间的相互化学反应受到抑制。运用4Al+3TiO_2+3C自蔓延高温合成反应制备了Al_2O_3-TiC陶瓷复合材料。 相似文献
3.
高效液膜分离富集镍基合金镀层中稀土总量 总被引:2,自引:0,他引:2
用TBP-TTA(协同流动载体)、SPAN80和煤油高效液膜体系,研究∑RE^3+迁移行为。在适宜条件下,10min内,∑RE^3+的迁移率达99.5%以上。在同样条件下,常见共存金属离子如Fe^3+、Al^3+、Ni^2+、Cr^3+、Mo^6+、Cu^2+、Co^2+、Zn^2+、Cd^2+等均不被迁移;大量碱金属、碱土金属、Cl、NO3、ClO4、F、SiO3^2-、SO4^2-等离子也不影 相似文献
4.
本文研究了抗氧化剂Al8B4C7和Al4SiC4添加到含碳耐火材料中的性状和效果,讨论了其抗氧化的机量。Al8B4C7及Al4SiC4的抗水化性能良好,故可实际应用,Al8B4C7和Al24SiC4在耐火材料表面和CO(气)反应,分别生成Al2O3-B2O3和A2O3-SiO2保护层,抑制了耐火材料的氧化。 相似文献
5.
硅酸盐水泥熟料的铁相,是C2F-C6AF2-C4AF-C6A2F连续固溶体。一般煅烧条件下,其铁相主要为C4AF。引入一定量的含矿化离子的工业废渣配料,可以增加Al2O3在铁相中的固溶量,从而可得到以C4AF-C6A2F为主的铁相,其摩尔比大体aO:Al2O3:Fe2o3=5:1.5:1。这种熟料及其磨制的普通硅酸盐水泥,具有良好的耐磨性及很小的干缩率。 相似文献
6.
7.
Pr^3+掺杂的Cd3M2Ge3O12(M=Al,Ga)石榴石的阴极射线发光特性 总被引:3,自引:0,他引:3
首次报道Pr^3+分别激活的Cd3Al2Ge3O12(CAGG)和Cd3Ga2Ge3O12(CGGG)锗酸盐石榴石的阴极射线发光光谱,Pr^3+的4f能级发射强度与Pr^3+浓度关系以及粉红色较长余辉特性。与CAGG相比,发现在CGGG中Pr^3+的所有4f-4f跃迁发射峰位置向短波移动,并分析造成这种光谱“蓝移”的原因。 相似文献
8.
以二乙胺为例研究了胺对Ni(naph)2-Al(-Bu)3-BF3·OEt2+n—C8H17OH(简称Ni-Al-B+ROH)和Ni(naph)2-Al(i-Bu)3-BF3·OEt2+CH3COOC4H9(简称Ni—Al—B+BA)两体系聚合活性和聚合物分子量的影响,并与Ni—Al—B体系进行了对比.考察了通常条件下肢的允许含量,讨论了有胺存在时Ni/Bd、Al/Ni、Al/B摩尔比的变化对聚合规律的影响。结果表明:胺的含量高于20ppm时将使聚合活性和分子量降低,提高催化剂用量可以抑制胺的不利影响。 相似文献
9.
酸性膦酸酯钕盐催化聚合丁二烯的研究 总被引:3,自引:0,他引:3
以酸性膦酸酯(P507)钕盐(Nd)、Al(i-Bu)3(Al)和Al2Et3Cl3(Cl)为催化体系,已烷为溶剂,进行丁二烯(Bd)溶液聚合。催化剂采用Al+Nd+Cl的加料方式,Al/Nd=20(摩尔比,下同),Cl/Nd=3.0,室温下陈化2h以上,于50℃恒温水溶中聚合5h,可得到顺式-1,4含量高于97%,[η]大于9.0dL/g的聚合物。同时证明,在相同的催化剂组分配比及聚合条件下,该 相似文献
10.
11.
12.
13.
电解阳极间接氧化法处理制药废水的研究 总被引:4,自引:3,他引:4
通过在废水中加入NaCl电解质,考察了电解阳极间接氧化法制药废水的处理效果。实验分析了废水中电解质NaCl对制药废水电解过程中CODCr、色度去除的影响,并对不同用量NaCl电解效果进行了对比。另外还用电解质Na2SO4、NaNO3作了对比实验来说明NaCl产生的电解阳极间接氧化的存在。最后对甲红霉素废水进行中试实验,结果表明,NaCl电解产生的NaClO具有极强的氧化性,促进了CODCr的去除,同时还发现,废水中氨氮的存在不利于废水CODCr的去除。 相似文献
14.
T. Stoyanova Lyubenova J.B. Carda M. Ocaña 《Journal of the European Ceramic Society》2009,29(11):2193-2198
The synthesis of red–orange Cr-doped YCaAlO4 pigments has been improved (softer thermal conditions and lower environmental impact) and optimised by using the pyrolysis of aerosols method. We also study the crystallochemical features of the Cr chromophore with special emphasis on its oxidation state which has not been yet clarified, finding that Cr(III) and Cr(IV) species are present in the octahedral and interstitial tetrahedral sites of the YCaAlO4 lattice, respectively. Finally, the applicability of this system as ceramic pigment was tested using conventional industrial glazes. A change from orange to pink shades was detected after glaze firing, which is mainly attributed to the Cr3+ to Cr4+ oxidation. 相似文献
15.
Tianyuan Zhou Le Zhang Cen Shao Bingheng Sun Wei Bu Hao Yang Hao Chen Farida A. Selim Qitu Zhang 《Ceramics International》2018,44(12):13820-13826
Cr: YAG and Cr, Nd: YAG transparent ceramics have significant application prospects in solid state lasers, therefore a controllable charge state of Cr ion in Cr doped YAG transparent ceramics is necessary. In this study, a successful regulation of Cr charge state in both Cr, Nd: YAG and Cr: YAG transparent ceramics was achieved, by a simple optimizing the sintering additives. Both ceramics with the Cr doping concentration of 0.3?at% reached to the theoretical transmittance, after the vacuum sintering and the subsequent annealing process. It was found that by adopting silica additive, divalent charged Cr2+ ions could be detected from the vacuum sintered samples, and they were transferred into trivalent state after further annealing in air. Meanwhile, by vacuum sintering ceramics with divalent additives (CaO and MgO), a stable trivalent charged Cr ion could be obtained, and the subsequent air annealing process indicated a significant conversion from Cr3+ to Cr4+. Further increasing the Cr concentration was not benefit to the optical quality as well as the conversion of Cr3+ ion in Cr, Nd: YAG transparent ceramics. 相似文献
16.
CCl2F2(CFC-12)曾广泛用作制冷剂和推进剂,是消耗臭氧层的罪魁祸首,选取何种温度将CCl2F2转化为高附加值的四氟甲烷(CF4)是本研究的目标。通过沉积沉淀法制备了一系列不同温度焙烧的CrAlF催化剂,并用于气相氟化CCl2F2反应合成CF4,600℃焙烧的催化剂活性最好,400℃反应温度下合成CF4的生成产率约为92%。XRD、Raman和UV-Vis分析结果表明随着焙烧温度升高,催化剂表面的晶相Cr2O3的含量增加。晶相Cr2O3很难被活化而形成活性物种,因而催化剂活性与CrAlF催化剂表面Cr2O3的含量有关。CrAlF-6催化剂活性最高归因于其表面相对最低的Cr2O3含量。研究发现载体Al2O3经氟化后生成AlF3,并且形成的小晶粒AlF3载体有利于获得较高的催化活性。催化剂失活的主要原因可能与催化剂表面CrO的含量增加以及晶粒增大有关。 相似文献
17.
Chung-Hung Tam Shih-Chin Lee Shih-Hsien Chang Tzu-Piao Tang Hsin-Hung Ho Hui-Yun Bor 《Ceramics International》2009,35(2):565-570
Commercial as-hp (hot pressing) treated Cr–Si targets are used throughout this study, with three different compositions: Cr20–Si80, Cr35–Si65 and Cr50–Si50. To evaluate the effects of microstructure and properties of as-hp treated Cr–Si targets by hot isostatic pressing (HIP) SEM, XRD and porosity inspections were performed. The experimental results showed that the 1373 K, 1750 MPa, 4 h HIP treated with three different Cr–Si targets had suppressed porosities successfully. The most efficient was Cr50–Si50 target subjected to HIP treatment. Porosity decreased about 60% after HIP treatment, and both the nitrogen and oxygen concentrations of the targets were slightly increased after HIP treatment. This was especially true for the single silicon in Cr–Si targets such as Cr20–Si80 and Cr35–Si65. The aim of this paper is to discuss these methods and finding suitable temperatures for the HIP for Cr–Si targets. 相似文献
18.
FTIR spectroscopy was applied to study the initial steps of ethylene polymerization on reduced chromia-silica (0.5 wt% Cr/SiO2). To decrease the speed of the reaction small doses of gas were introduced to the catalyst in each run and C2D4 was used to confirm band assignments. At the initial steps of the reaction only ethylene molecules coordinated to probably Cr
A
2+
cations were observed. The concentration of such complexes was estimated to be about 50% of the total amount of Cr atoms in the sample. The FTIR spectrum of the polymer formed at the initial doses of C2H4 (when [C2H4] [Cr]) was found to be slightly different from that formed after excess ethylene was introduced onto the catalyst ([C2H4] > [Cr]). 相似文献
19.
机械加工厂的排放废水是一个Cr(Ⅵ)/苯酚共存的体系,一般处理工艺难以同时去除.文章采用商品氧化钛P25和TiO2晶须分别在高压汞灯和低压汞灯的条件下对Cr(Ⅵ)/苯酚共存体系进行了光催化降解研究.结果表明,Cr(Ⅵ)/苯酚共存体系中Cr(Ⅵ)的光催化还原和苯酚的光催化氧化可以产生协同效应,且协同效应的产生与催化剂和光源都相关.仅在低压汞灯/TiO2晶须体系中出现了协同效应,反应4min时Cr(Ⅵ)和苯酚的转化率分别比单独体系中的提高了15%和30%.该协同效应表明,光催化技术为机械加工厂的排放废水提供了一种可行的水处理方法. 相似文献