帘线钢氮化钛夹杂的控制实践

为了降低帘线钢中的氮化钛夹杂,鞍钢股份有限公司炼钢总厂采用专用合金和专用钢水罐、转炉工序采取高拉碳一次点吹和低氮增碳剂、LF炉工序造泡沫渣和钢水弱脱氧、机前采取长水口吹氩等措施。结果表明,帘线钢氮化钛夹杂罚分由平均32.5降低到14.8,帘线钢实物质量得到提高。

Effect of bias voltage on microstructure and nanomechanical properties of Ti films

In order to investigate nanomechanical properties of nanostructured Ti metallic material, pure Ti films were prepared by magnetron sputtering at the bias voltage of 0-140 V. The microstructure of Ti films was characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM） and high-resolution transmission electron microscopy（HRTEM）. It is interesting to find that the microstructure of pure Ti films was characterized by the composite structure of amorphous-like matrix embodied with nanocrystallines, and the crystallization was improved with the increase of bias voltage. The hardness of Ti films measured by nanoindentation tests shows a linear relationship with grain sizes in the scale of 6-15 nm. However, the pure Ti films exhibit a soft tendency characterized by a smaller slope of Hall-Petch relationship. In addition, the effect of bias voltage on the growth orientation of Ti films was discussed.

Effect of frequency and pulse-on time of high power impulse magnetron sputtering on deposition rate and morphology of titanium nitride using response surface methodology

Titanium nitride thin films were deposited on silicon by high power impulse magnetron sputtering(HiPIMS)method at different frequencies(162-637 Hz)and pulse-on time(60-322μs).Response surface methodology(RSM)was employed to study the simultaneous effect of frequency and pulse-on time on the current waveforms and the crystallographic orientation,microstructure,and in particular,the deposition rate of titanium nitride at constant time and average power equal to 250 W.The crystallographic structure and morphology of deposited films were analyzed using XRD and FESEM,respectively.It is found that the deposition rate of HiPIMS samples is tremendously dependent on pulse-on time and frequency of pulses where the deposition rate changes from 4.5 to 14.5 nm/min.The regression equations and analyses of variance(ANOVA)reveal that the maximum deposition rate(equal to(17±0.8)nm/min)occurs when the frequency is 537 Hz and pulse-on time is 212μs.The experimental measurement of the deposition rate under this condition gives rise to the deposition rate of 16.7 nm/min that is in good agreement with the predicted value.

Band Gap Control for （Fe, Ti）-Containing Mesoporous Silica Nanoparticles Using the Photo-Assisted Deposition Technique

It is a great advantage to design advanced materials with outstanding porosity and controllable band gab. In this study, （Fe, Ti）-containing mesoporous silica （x Fe/Ti-HMS） nanoparticles were prepared by a photo-assisted deposition PAD technique, where x is a nominal composition ofFe （l to 4 wt%））. The prepared samples were characterized by DR-UV, XRD, and TEM techniques. The results showed the insertion of Fe into intra-framework of Ti-HMS resulted in a gradual narrowing of the band gap of Ti-HMS samples with increment of Fe wt%. TEM observations reveal that Fe nanoparticles are evenly distributed within Ti-HSM matrix at different Fe wt%. Such results indicate the possibility to control the band gap of a single-site photocatalyst （Ti-HMS） by coupling it with the conventional nano-sized Fe catalysts.

Influence of carbon and yttrium co-doping on the photocatalytic activity of mixed phase TiO_2

Mixed phase TiO2photocatalysts doped with C and Y were synthesized by a sol‐gel process.The effects of C and Y doping and annealing temperatures on the structural and optical properties,and photocatalytic activity were investigated.We found that both C and Y doping can broaden the absorption spectrum of TiO2to the visible light region and inhibit recombination of photogenerated electron/hole pairs.The incorporation of Y into the TiO2lattice inhibited growth of crystalline grains,which increased the specific surface area and enhanced the photocatalytic activity.The photocatalytic performance of the samples was investigated in the photocatalytic degradation of methyl blue under visible light irradiation.The rate of methyl blue degradation over the(C,Y)‐co‐doped TiO2sample was much higher than those of undoped TiO2,C‐TiO2,and Y‐TiO2.Additionally,the apparent first‐order rate constant of the co‐doped sample was3.5times as large as that of undoped mix phase TiO2under the same experimental conditions.The enhanced photocatalytic activity can be attributed to the synergic effect of(C,Y)‐co‐doping and the formation of an appropriate crystalline structure.

Preparation and Characterization of Nano-Particles PZT Ferroelectric Thin Films by RF-Magnetron Sputtering

Pt/Ti bottom electrodes were fabricated on SiO2/Si substrates by magnetron dual-facingtarget sputtering system. Lead zirconate titanate（PZT） thin films were deposited on Pt/Ti/SiO2/Si substrates by radio frequency （RF） magnetron sputtering system. The thickness of PZT thin films which were deposited for 5 h was about 800 nm. XRD spectra show that PZT thin films deposited in Ar ambience and rapid-thermal-annealed for 20 min at 700 ℃ have good crystallization behavior and perovskite structure. AFM micrographs show that mean diameter of crystallites is 70 nm and surface structures of PZT thin films are uniform and dense. Raw mean, root mean square roughness and mean roughness of PZT thin films are 34..357 rim, 2. 479 nm and 1. 954 nm respectively. As test frequency is 1 kHz, dielectric constant of PZT thin films is 327.5. Electric hysteresis loop shows that coercive field strength, residual polarization strength and spontaneous polarization strength of PZT thin films are 50 kV/cm, 10μC/cm^2 and 13μC/cm^2 respectively.

Characterization of DC magnetron sputtering deposited thin films of TiN for SBN/MgO/TiN/Si structural waveguide

Optimal parameters for depositing Titanium nitride （TIN） thin films by DC reactive magnetron sputtering were determined. TiN thin films were deposited on Si （100） substrates by DC reactive magnetron sputtering, at different temperatures, different electrical current values, and different N2/Ar ratios. Structural characteristics of TiN thin films were measured by X-ray diffraction （XRD）; surface morphology of the thin films was characterized using an atomic force microscope （AFM）. The electric resistivity of the TiN films was measured by a four-point probe. In the result, temperature is 500℃, electrical current value is 1.6 A, pure N2 is the reacting gas, TiN thin film has the preferred （200） orientation, resistance is small enough for its use as bottom electrodes.

Effect of TiO_2 addition on zirconia-mullite composites fabricated by in-situ controlled crystallization of Si-Al-Zr-O amorphous bulk

Zirconia-mullite composite ceramics were fabricated by in-situ controlled crystallization of Si-Al-Zr-O amorphous bulk. The effects of TiO2 addition on the fabrication of zirconia-mullite composites were investigated. The ultra-fine zirconia-mullite composite ceramics were prepared from the amorphous bulk treated at 980 ℃ for nucleation and 1 140℃ for crystallization. The phase transformation of the ceramics was examined using differential scanning calorimetry （DSC） and X-ray diffractometry （XRD）. The microstructural features of the samples were evaluated with scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDX） and transmission electron microscopy （TEM）. The mechanical properties were also determined using Vickers indentation. The results show that the TiO2 additives with mass fraction of 1%-7% reduce the formation temperature of t-ZrO2 and mullite. When the mass fraction of TiO2 additives is less than 5%, the phases do not change, and most of TiO2 dissolves in ZrO2. When the mass fraction of TiO2 additives is over 5%, the excessive TiO2 forms a new phase, ZrTiO4. Meanwhile, the results also show that TiO2 additives have a great impact on the microstructure and mechanical properties of zirconia-mullite composites. As the TiO2 content increases from 1% to 7% （mass fraction）, the grain size and the Vickers hardness of zirconia-mullite composites increase. The composite with 3% （mass fraction） TiO2 additives attains relatively higher fracture toughness.

Microstructure and optical properties of TiO_2 thin films deposited at different oxygen flow rates

To research the influence of oxygen flow rate on the structural and optical properties of TiO2 thin film,TiO2 films on glass were deposited by reactive magnetron sputtering.The microstructure and optical properties were measured by X-ray diffractometry,AFM and UV-VIS transmittance spectroscopy,respectively.The results show that the films deposited at oxygen flow rate of 10 mL/min has the lowest roughness and the highest transmittance.The absorption angle shifts to longer wavelengths as oxygen flow rates increase from 5 to 10 mL/min,then to shorter ones as the oxygen flow rate increase from 10 to 30 mL/min.The band gap is 3.38 eV,which is nearly constant in the experiment.For the TiO2 thin films deposited at 10 mL/min of oxyge flow rate,there are nano-crystalline structures,which are suitable for anti-reflection(AR) coating in the solar cells structure system.

TiO_2 mesocrystals: Synthesis, formation mechanisms and applications

Mesocrystals, which are assemblies of crystallographically oriented nanocrystals, have received increasing attention due to their unique properties such as high crystallinity, high porosity, oriented subunit alignment, and similarity to highly sophisticated biominerals. However, the controlled synthesis of TiO 2 mesocrystals has not been realized until recently, probably because of the difficulty in accurately controlling the reaction processes that produce TiO 2 crystals. In this review, recent advances in the synthesis and applications of TiO 2 mesocrystals are summarized with particular attention paid to the mechanisms of their formation. Three typical pathways for the preparation of TiO 2 mesocrystals are discussed, namely topotactic transformation, direct synthesis in solution, and growth on supports. The potential applications of TiO 2 mesocrystals in lithium ion batteries, photocatalysis, enzyme immobilization, and antireflection materials are also described.

Directing nucleation and growth kinetics in solution-processed hybrid perovskite thin-films

A heightened understanding of nucleation and growth mechanisms is paramount if effective solution processing of organic-inorganic perovskite thin-films for optoelectronic applications is to be achieved. Many fabri- cation techniques have been utilized previously to develop high-performance perovskite layers but there remains an absence of a unifying model that describes accurately the formation of these materials from solution. The present study provides a thorough analysis of nucleation and growth kinetics underpinning the development of hybrid organic-in- organic perovskite thin-films. Through precise control of the perovskite growth conditions the spacing of heteroge- neous nucleation sites was varied successfully from several hundred nanometers to several hundred microns. The crystalline regions surrounding these nuclei were found to comprise clusters of highly-oriented crystal domains exceed- ing 100 pm in diameter. However, no beneficial correlation was found between the size of these well-oriented grain-clus- ters and the optoelectronic performance. The formation of the perovskite microstructure features characteristics of both classical and non-classical growth mechanisms. The insights into perovskite thin-film growth developed by the present study provide clear implications for the development of future hybrid perovskite microstructures.

Control of organic–inorganic halide perovskites in solid-state solar cells: a perspective

Since the year of 2009 when the first appli- cation of organohalide lead perovskite as the light har- vester in solar cells was reported, tremendous attention has been devoted to these new types of perovskite-based solid-state solar cells and remarkable power conversion efficiency of over 20 % has been achieved to date. In this review, we first introduce the properties of organic- inorganic halide perovskites and then focus on the notable achievements made on the perovskite layer to improve the power conversion efficiency of solid-state perovskite solar cells, which is featured by process engineering of the state-of-the-art lead methylammoni- um triiodide perovskite and material control of lead triiodide perovskites and other newly emerged per- ovskites. In the end, we wish to provide an outlook of the future development in solid-state perovskite solar cells. Provided that the instability and toxicity of solid- state perovskite solar cells can be solved, we will wit- ness a new era for cost-effective and efficient solar cells.

Tailoring electrical property of the low-temperature processed SnO_2 for high-performance perovskite solar cells

Herein, we for the first time doped Nb^5+into the low-temperature(<100°C) SnO2sol-gel route to tailor the electrical property of SnO2 layers and the band alignment between SnO2 and the normally used mixed perovskites. The results revealed that proper Nb5+doping increased the conductivity of the SnO2 electron transport layer(ETL), and the conduction band(CB) level of the SnO2 ETL was shifted down to approach the CB level of perovskites, which facilitated the electron injection from perovskite to SnO2, accelerated the charge transport, and reduced the non-radiative recombination, leading to improved power conversion efficiency from18.06% to 19.38%. The Nb^5+doping process provided an efficient route for fabricating high-efficiency perovskite solar cells(PSCs) at a temperature lower than 100°C, and promoted the commercialization progress of PSCs.

Inverted polymer solar cells with TiO_2 electron extraction layers prepared by magnetron sputtering

TiO2 thin films deposited by magnetron sputtering possess excellent optical transmittance,high refractive index,good adhesion and chemical stability.In this manuscript,TiO2 thin films deposited by magnetron sputtering was used for the first time as an electron extraction layer in inverted polymer solar cells(IPSCs),and the effect of the TiO2 thickness on the photovoltaic performance of P3HT:PC61BM IPSCs was investigated.The highest PCE value of 3.75%was obtained when the thickness of TiO2thin films was in the range between 42 nm and 73 nm.The absorption properties,morphology and structure of the TiO2 films were characterized by UV-Vis spectroscopy,SEM and Raman spectroscopy,and were related to the device performance of P3HT:PC61BM IPSCs.The results indicate that TiO2 films deposited by magnetron sputtering are an excellent electron extraction layer for IPSCs.

Electron transport layer driven to improve the open-circuit voltage of CH_3NH_3PbI_3 planar perovskite solar cells

Suitable electron transport layers are essential for high performance planar perovskite heterojunction solar cells. Here, we use ZnO electron transport layer sputtered under oxygen-rich atmosphere at room temperature to decrease the hydroxide and then suppress decomposition of perovskite films. The perovskite films with improved crystallinity and morphology are achieved. Besides, on the ZnO substrate fabricated at oxygen-rich atmosphere, open-circuit voltage of the CH_3NH_3PbI_3-based perovskite solar cells increased by 0.13 V.A high open-circuit voltage of 1.16 V provides a good prospect for the perovskite-based tandem solar cells. The ZnO sputtered at room temperature can be easily fabricated industrially on a large scale, therefore, compatible to flexible and tandem devices. Those properties make the sputtered ZnO films promising as electron transport materials for perovskite solar cells.