Preparation of sintered foam glass with high fly ash content

Foam glasses with 50 wt.%, 60 wt.% and 70 wt.% fly ash are prepared using fly ash and flux agent sodium borate with sodium silicate as foaming agent at the temperature of 800 °C. Heat treatment at 800 °C for 1 h of pellets having different fly ash mass percentages results in well-sintered bodies of dark gray color featuring a vitreous aspect with smooth surface. The effect of amount of fly ash on the density, porosity, mechanical strength and microstructure is evaluated. The experimental results show that the foam glass with 70 wt.% fly ash exhibits the excellent comprehensive properties and the suitable sintered temperature is 800 °C.     

核壳结构正极材料界面设计与性能研究

核壳结构电池材料能从核心和壳体两方面产生协同作用,具有比容量高、氧化还原可逆性好、离子扩散速率高、成本低、安全性强等优点,在电池材料研究中有广泛应用。三元电池材料的核壳结构设计主要分为非电活性材料核壳结构设计、普通核壳结构设计、浓度梯度核壳结构设计、全浓度梯度核壳结构设计等;核壳结构三元电池材料的合成方法主要分为：化学共沉淀法、水热法、溶胶-凝胶法等,综述了核壳结构电池材料热力学、电化学、动力学性能,对核壳结构电池材料理论计算、数值模拟的研究现状和应用进行了阐述,最后简述了核壳结构正极材料的应用和展望。     

优质压裂泵泵阀分析

压裂泵是油气增产的关键设备之一。由于工作条件相当恶劣,压裂泵的易损件——阀的使用寿命相当低,甚至于不足以完成一次作业(约2.5小时).为了提高泵阀使用寿命,收集现场使用的优质泵阀,进行材质、金相、宏观和微观失效分析,从中得出一些有益的认识,用来改进国产泵阀、提高其使用寿命以适应压裂酸化工艺的发展是有必要的。     

半导体量子点玻璃的研究进展

介绍了半导体量子点材料禁阻类型,详细阐述了共熔法、溶胶-凝胶法、离子注入法等半导体量子点玻璃材料的制备方法,探讨了半导体量子点玻璃的尺寸效应、禁阻效应、库仑阻塞效应和非线性光学效应等特性及其未来应用前景.     

泥浆泵双金属缸套磨损失效机理及其材质匹配试验

对现场收集的用于不同地层使用寿命不等的10支高铬铸铁失效缸套,进行金相分析、扫描电镜表面形貌分析和磨屑的铁谱分析.进而对高铬铸铁缸套的磨损失效过程及起主导作用的磨损机理进行了详细阐述,得出了一些新的具有理论价值的认识.根据这些认识对缸套材质进行了合理的匹配试验研究.经现场试验表明,将现行缸套含铬量降低50%左右,其寿命不变,而成本却下降17.8%,为开发新型缸套和降低成本提供了理论依据.     

陶瓷结合剂与金刚石高温下的界面结合机理研究

本文研究了陶瓷结合剂与金刚石的界面反应、界面结构和结合状况.通过对改性Li2O-Al2O3-SiO2微晶玻璃和B2O3-PbO-ZnO-SiO2低熔玻璃镀钛、不镀钛金刚石试样的电镜分析、XRD分析以及两种结合结合剂与镀钛、不镀钛金刚石试样的抗折强度测定,研究了结合剂(Li2O-Al2O3-SiO2微晶玻璃和B2O3-PbO-ZnO-SiO2玻璃)与金刚石(镀钛和不镀钛)的结合机理和结合状况.发现:改性Li2O-Al2O3-SiO2玻璃经过合适的热处理工艺能在金刚石试样中出现以Li2Al2Si3O10为主晶相的微晶体,试条的抗折强度是B2O3-PbO-ZnO-SiO2低熔玻璃金刚石试样的2.5倍以上;镀钛金刚石与微晶玻璃结合剂之间产生化学结合,抗折强度比不镀钛金刚石试条提高20%以上;而对B2O3-PbO-ZnO-SiO2玻璃结合剂而言,金刚石表面镀钛对试条的抗折强度的提高无明显作用.     

Mg取代Y对Y-Mg-Si-Al-O-N氧氮玻璃性质的影响

为了研究Y-Si-Al-O-N玻璃中阳离子的组成和配比对玻璃的热性能、机械性能和化学稳定性的影响,通过Mg取代Y-Si-Al-O-N玻璃中的部分Y,制备了Y-Mg-Si-Al-O-N玻璃样品.用X射线衍射仪、差示扫描量热仪、金相显微镜和红外吸收光谱仪对样品进行了分析.结果表明:与Y-Si-Al-O-N氧氮玻璃相比,Y-Mg-Si-Al-O-N氧氮玻璃的玻璃化温度和抗20%HF腐蚀能力均急剧降低,显微硬度和抗弯强度则明显增强;Y-Mg-Si-Al-O-N删玻璃开始析晶的温度大大降低,析晶温度范围明显变宽,析晶能力明显增强.     

Comparison between vitrified bond and resin bond diamond grinding wheel in grinding PDC

In this research, the advantages and disadvantages of the cylindrical grinding process of Polycrystalline Diamond Compacts (short for PDC) with vitrified and resin bond diamond grinding wheel are compared. The research results show that the vitrified bond diamond grinding wheels, which use Ti-coated diamond grains as abrasive and glass ceramic as bond, have many advantages in grinding PDC . Compared with resin diamond grinding wheel,vitrified bond wheels lead to 35% grinding cost reduced, 40% grinding time of each PDC saved, and the size precision of PDC improved (from ±0.03mm to ±0.01mm). When grinding feed is ＜0.10 mm, the grinding ratio increases with increased grinding feed. However, when the grinding feed exceeds 0.10 mm, the grinding radio decreases rapidly with the increasing of grinding feed. The disadvantage of this kind of grinding wheel is that the brightness of the ground PDC cylinder is not as shining as that processed by resin bond diamond grinding wheel.     

PCD刀具刃磨用细粒度陶瓷结合剂金刚石砂轮的研制及应用

探讨了刃磨PCD刀具用细粒度陶瓷结合剂金刚石砂轮的制造工艺与应用,选用Li2O-ZnO-SiO2微晶玻璃作结合剂,研究了砂轮中金刚石浓度、结合剂含量及造孔剂种类、含量变化对砂轮磨削性能的影响。     

Crystallization,structure and properties of MgO-Al2O3-SiO2 highly crystalline transparent glass-ceramics nucleated by multiple nucleating agents

Generally, highly crystalline transparent glass-ceramics possess excellent physical and chemical properties compared to organic and other inorganic optical materials. We have successfully prepared highly crystalline transparent glass-ceramics in the MgO-Al₂O₃-SiO₂ system by "extreme-time" nucleation & "finite-time" crystallization processes using P₂O₅, ZrO₂ and TiO₂ as multiple nucleating agents. The results revealed that the crystallization of glass is controlled by a three-dimensional interfacial crystal growth process. These glass-ceramics mainly consisted of cordierite crystals with a residual glassy phase, and crystallinity increased with crystallization time, but light transmittance decreased with crystallization time due to enlarged grain sizes. EDS mapping revealed a uniform distribution of elements within the glass-ceramic. In the optimal preparation condition (825?°C/96?h?+?990?°C/3?h), these glass-ceramics exhibited a high crystallinity (87.3?vol. %), high transmittance (78%), and excellent mechanical properties. This work provides a roadmap for preparing highly crystalline transparent glass-ceramics for applications in optical engineering.