Gemini季铵盐粘土稳定剂的合成及其防膨性能评价

采用环氧氯丙烷和三甲胺为原料合成了粘土稳定剂Gemini季铵盐,探讨了合成条件并测试了其防膨性能.确定Gemini季铵盐的最佳合成条件如下:反应温度为96℃,反应时间为8 h,n(三甲胺):n(三甲胺盐酸盐):n(环氧氯丙烷)为1.2:1:1,反应溶剂选用醇-水混合溶剂,溶剂占反应体系总质量的35%.此时所得产物收率为86.5%.该Gemini阳离子表面活性剂防止粘土膨胀性能良好,防膨率达到88.7%.     

Studies on salts of amine‐containing polymers with benzoic acids. III. Poly(N,N‐dimethylaminoethyl methacrylate‐g‐polyethylene) with benzoic acids

Poly(N,N‐dimethylaminoethyl methacrylate) [poly(DMAEMA)] was grafted onto a commercial polyethylene film by means of γ‐irradiation, and the grafted films were reacted with various liquid‐crystal‐forming benzoic acids. When polymeric salts consisting only of poly(DMAEMA) and the benzoic acids were heated, dissociation of salts was observed, but with poly(DMAEMA) grafted onto polyethylene films, salt dissociation or crystallization of dissociated acids could be avoided, and interesting morphologies, including liquid‐crystal phases, were observed for the systems of benzoic acids–poly(DMAEMA‐g‐polyethylene). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 972–978, 2000     

Na2WO4-WO3-ZnO体系熔盐镀钨

对Ｎａ２ＷＯ４－ＷＯ３－ＺｎＯ体系熔盐镀钨工艺进行了详细研究,得到了获得金属钨镀层的工艺条件。结果表明：在空气气氛中,当氧化钨的浓度为１５％～３０％时,于８５０～９５０℃能得到金属钨镀层且镀层表面平整;当其它条件都相同时,在铜基体上获得钨镀层比钼基体上所需的温度略高一些;扫描电镜照片显示钨镀层与钼基体之间有明显分界面,元素线扫描结果证实镀层与钼基体间扩展层厚度仅为２．５μｍ,基本不形成扩散层;不同     

Evaluation of Tribological Properties of Sulfur- and Phosphorous-Free Quinolinium Salts and Their Correlation with Quantum Chemical Parameters

For developing antiwear additives with high efficiency but with low sulfated ash, phosphorous, and sulfur (SAPS), N-substituted quinolinium halides, [DIP-Q]⁺Br^? [DIP-Q=1-(3-(1,3-dioxoisoindolin-2-yl)propyl)quinolon-1-ium], [DIE-Q]⁺Br^? [DIE-Q=1-(3-(1,3-dioxoisoindolin-2-yl)ethyl)quinolon-1-ium], [P-Q]⁺I^? [P-Q=propylquinolon-1-ium], and [M-Q]⁺I^? [M-Q=methylquinolon-1-ium] have been prepared and characterized by ¹H- and ¹³C-NMR spectroscopic techniques. The tribological performance of these quinolone-based quaternary salts as antiwear additives in paraffin oil has been assessed on a four-ball test rig. The observed results have been compared with those of zinc dialkyldithiophosphate (ZDDP), a high SAPS additive. The tribotesting of these additives has been performed using 1% w/v additives concentration at different loads and times. The potential of these compounds as antiwear additives is evident from their observed tribological data: mean wear scar diameter (MWD), friction coefficient (µ), mean wear volume (MWV), and wear rates. All of the quinolinium derivatives prove to be better antiwear additives than ZDDP. Among the tested synthesized compounds, [DIP-Q]⁺Br^? exhibits the best tribological behavior followed by [DIE-Q]⁺Br^?, [P-Q]⁺I^?, and [M-Q]⁺I^?. The surface topography of worn surface studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM) shows that surface roughness is reduced to a greater extent in case of quinolinium derivatives than lubrication with ZDDP or base oil alone. Energy-dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analysis of worn surfaces in the presence of quinolinium additives shows that the tribofilm is composed of FeBr₃, Fe₃O₄, and organic compounds containing carbonyl and imine bonds. Theoretical investigations using quantum chemical calculations are indicative of significant chemical interactions of these quinolinium additives with metal surfaces, which is strongly supported by the observed experimental data.     

Atom site preference and γ′/γ mismatch strain in NiAlCoTi superalloys

The structure and chemistry of NiCoAlTi quaternary superalloys are investigated at the microstructural and atomic scale. Atom probe tomograghy (APT) is used to quantify phase compositions and elemental partitioning behavior. Using aberration corrected electron microscopy, the site occupancy of the atoms within the A₃ B structure (L1₂–type) γ′ phase is determined via atomic resolution energy dispersive X-ray spectroscopy (EDX). Ni is observed to preferentially occupy the A sub-lattice positions for all alloys, while Al and Ti occupy the B sub-lattice. In contrast, Co's site preference changes from a random distribution to the A sub-lattice as the alloy composition changes, in agreement with theoretical predictions from literature. Finally, the lattice strain across the γ′/γ interfaces is measured as a function of alloy composition.     

L-抗坏血酸-2-硫酸酯盐的合成

以焦硫酸钾为酯化剂,以吡啶为溶剂合成了Ｌ－ 抗坏血酸的稳定衍生物 Ｌ－ 抗坏血酸－ ２ － 硫酸酯二钾盐。该衍生物具有弱酸性,在弱碱中稳定。合成方法操作简便,收率高。     

预应力锚索在第四系边坡支护工程中的应用

针对新桥硫铁矿矶山东部露天采场上盘边坡特殊工程地质条件、系统阐述了预应力锚索,锚喷网联合等项综合技术措施在第四系边坡支护中的应用,为土质边坡大面积加固积累了成功经验。     

Hot corrosion of YSZ/Al2O3 dispersed NiCrAlY plasma-sprayed coatings in Na2SO4-10 wt.% NaCl melt

This study examines the effect of ytrria stabilized zirconia (YSZ) dispersion on hot corrosion behaviour of NiCrAlY bond coat. Hot corrosion studies were conducted on NiCrAlY and NiCrAlY containing 25, 50 and 75 wt.% YSZ coatings obtained through the air plasma spray technique, in Na₂SO₄ + 10 wt.% NaCl environment at 800 °C. The results show that YSZ dispersion lowers the overall hot corrosion tendency of the NiCrAlY, though it enhances the inherent hot corrosion tendency of its metallic constituent (NiCrAlY). Furthermore, there exists a threshold oxide level beyond which it adversely affects the hot corrosion of the coating.     

The growth of single Fe2B phase on low carbon steel via phase homogenization in electrochemical boriding (PHEB)

In this study, we introduce a new electrochemical boriding method that results in the formation of a single-phase Fe₂B layer on low carbon steel substrates. Although FeB phase is much harder and more common than Fe₂B in all types of boriding operations, it has very poor fracture toughness; hence, it can fracture or delaminate easily from the surface under high normal or tangential loading. We call the new method “phase homogenization in electrochemical boriding” (PHEB), in which carbon steel samples undergo electrochemical boriding for about 15 min at 950 °C in a molten electrolyte consisting of 90% borax and 10% sodium carbonate, then after the electrical power to the electrodes is stopped, the samples are left in the bath for an additional 45 min without any polarization. The typical current density during the electrochemical boriding is about 200 mA/cm². The total original thickness of the resultant boride layer after 15 min boriding was about 60 μm (consisting of 20 μm FeB layer and 40 μm Fe₂B layer); however, during the additional phase homogenization period of 45 min, the thickness of the boride layer increased to 75 μm and consisted of only Fe₂B phase, as confirmed by glancing-angle x-ray diffraction and scanning electron microscopy in backscattering mode. The microscopic characterization of the boride layers revealed a dense, homogeneous, thick boride layer with microhardness of about 16 GPa. The fracture behavior and adhesion of the boride layer were evaluated by the Daimler-Benz Rockwell C test and found to be excellent, i.e., consistent with an HF1 rating.     

碳纤维表面熔盐反应制备TiC涂层

采用熔盐反应法在碳纤维表面反应形成了TiC涂层,利用XPS,XRD和SEM对涂层的化学组成、相组成和微观结构进行了分析和表征,研究了反应温度和保温时间对涂层厚度和形貌的影响.结果表明:碳纤维表面形成的是含有少量自由碳的TiC涂层,涂层形貌与原碳纤维表面形貌相似;TiC涂层的厚度随反应温度、保温时间的增加而增加,在700...