硫酸法制取金红石型钛白粉的新工艺研究

通过系统试验,用筛选出的最佳晶型转化剂直接加入到硫酸氧钛水解的产物中,在最佳工艺条件下,经过煅烧和处理后,可生产出金红石型钛白粉。该工艺可为传统硫酸法制取钛白粉技术改革提供重要依据。     

Rheological and volumetric properties of TiO2-ethylene glycol nanofluids

Homogeneous stable suspensions obtained by dispersing dry TiO₂ nanoparticles in pure ethylene glycol were prepared and studied. Two types of nanocrystalline structure were analyzed, namely anatase and rutile phases, which have been characterized by scanning electron microscopy. The rheological behavior was determined for both nanofluids at nanoparticle mass concentrations up to 25%, including flow curves and frequency-dependent storage and loss moduli, using a cone-plate rotational rheometer. The effect of temperature over these flow curve tests at the highest concentration was also analyzed from 283.15 to 323.15 K. Furthermore, the influence of temperature, pressure, nanocrystalline structure, and concentration on the volumetric properties, including densities and isobaric thermal expansivities, were also analyzed.     

水热晶化法制备TiO2纳米粉末

本文采用水热晶化法成功地合成了粒径为７ｎｍ的锐钛矿相ＴｉＯ２纳米粉末。研究了热处理温度对所得纳米ＴｉＯ２粉的影响，ＴｉＯ２纳米粉从２００℃至８００℃之间经历了锐钛矿—锐钛矿与金红石共存—金红石的相变。     

Phase-microstructure-property relationship in high quality factor MgO-Al2O3-SiO2-TiO2-La2O3 glass-ceramics

MgO-Al₂O₃-SiO₂-TiO₂-La₂O₃ glass-ceramics were investigated with respect to the phase compositions and the microstructure as well as the microwave dielectric properties. Indialite, magnesium aluminum titanate (MAT, Mg₄Al₂Ti₉O₂₅), perrierite, and spinel were the main crystal phases in the studied 1.8MgO-1.2Al₂O₃-2.8SiO₂-1.4TiO₂-xLa₂O₃ (x=0.4, 0.3, 0.2) glass-ceramics. Mg₄Al₂Ti₉O₂₅ was detected inside the indialite domain as well as at the boundary while no decomposition product (rutile) is found, proving that Mg₄Al₂Ti₉O₂₅ is fully stabilized. After heat-treatment at 1200 °C, the quality factor (Q×f) of the glass-ceramics increases from 27,500 to 40,000 GHz with decreasing La₂O₃ concentrations. This is caused by the formation of more indialite and MAT. Meanwhile, the temperature coefficient (τ_f) shifts positively from −95 to −65 ppm/°C because of the smaller perrierite concentration. However, τ_f is still too negative due to the absence of rutile that possesses a high positive τ_f. For the 1.3MgO-1.2Al₂O₃-2.8SiO₂-1.4TiO₂-0.2La₂O₃ glass-ceramic with lower MgO molar composition, the peaks assigned to rutile is found and the chemical formula of MAT changes to MgAl₂Ti₃O₁₀ while spinel disappears. MgAl₂Ti₃O₁₀, which distributes mainly at the boundary, decomposes partially, leading to the precipitation of rutile inside the indialite domain. Thus, the τ_f of the glass-ceramic could be adjusted to near 0 ppm/°C with ε_r=9.9 and Q×f=28,600 GHz, which are favorable properties for microwave dielectric applications.     

Synthesis of highly hydrophobic rutile titania-silica nanocomposites by an improved hydrolysis co-precipitation method

Highly hydrophobic rutile titania-silica nanocomposites were synthesized by an improved hydrolysis co-precipitation method using low-cost sodium metasilicate and titanium oxysulfate (TiOSO₄) as precursors, followed sequentially by calcination at 800 °C and modification with trimethylchlorosilane (TMCS). It was found that the resulting TiO₂-SiO₂ nanocomposites had a Ti/Si molar ratio of 5:1 and exhibited single-phase rutile with a specific surface area of 269 m² g⁻¹. The addition of acetylacetone (AcAc) during the hydrolysis co-precipitation process played a key role in the growth of well-ordered TiO₂-SiO₂ crystallites since the hydrolysis rate of TiOSO₄ might be retarded due to the complexation of AcAc to the Ti atoms in TiOSO₄. The TMCS-modified TiO₂-SiO₂ nanocomposites exhibited a high root-mean-square (RMS) roughness of 22 nm and good hydrophobicity with a static contact angle of 143.7°, highlighting its potential application as a filler in exterior wall coatings.     

钛釉乳浊机理的研究

利用XRD、SEM等测试手段研究不同组成条件下钛乳浊乳的结构和性能,探讨钛乳浊釉的乳浊相的数量、种类、分布与其组成的关系,并得到钛乳浊釉的合理的组成范围,分析乳浊机理。     

金红石加碳氯化的热力学

运用HSC软件对金红石构成的多元、多相、多反应的复杂体系进行还原平衡组分的计算与分析。通过热力学计算,所得的结果表明：金红石在200℃的较低温条件下可完全转化。金红石加碳氯化反应随着温度的升高和配碳量的增加,体系中CO／CO2摩尔比值增大。只要维持理论配碳量和氯气用量,金红石即可完全转化。     

Columnar rutile TiO2 based dye-sensitized solar cells by radio-frequency magnetron sputtering

Columnar-structured rutile TiO₂ film with a thickness of 1.4 μm is prepared using the radio-frequency (RF) magnetron sputtering technique, for application in dye-sensitized solar cells (DSSCs). Pure rutile TiO₂ films are fabricated by controlling the substrate temperature during sputtering and using a substrate with a rough surface morphology. Successive substrate heating to 623 K induces the growth of a rutile TiO₂ film that has a specific direction in the (1 1 0) plane, which results in a decrease in the average grain size. This causes in an increase of dye uptake and thereby contributes to enhancement of the photocurrent in the DSSC.     

Low temperature stabilized rutile phase TiO2 films grown by sputtering

The deposition of rutile phase TiO₂ films on unheated substrates by radio frequency magnetron sputtering is elaborated. The effect of total pressure and O₂/Ar flow ratio on the growth of rutile film on different substrates has been studied thoroughly. The development of crystalline phase along with film deposition rate, surface morphology, optical transmission and band gap were also investigated for various growth conditions. It was found that the rutile phase crystallinity increased with decrease in total pressure and increase in O₂ flow. In addition, the grown rutile films have interesting optical characteristics such as high transmittance (~ 85%) and high refractive index (~ 2.7) with a band gap about 3.2 eV.     

工作气压对TiO2薄膜结构的影响

用射频磁控溅射方法以纯金属钛做靶材在氩氧混合气体中制备了TiO2薄膜，Raman光谱测量表明，工作气压从0．2Pa变化到2Pa时，TiO2薄膜的结构由金红石相变化到锐钛矿相，厚度对TiO2薄膜结构没有明显影响．