不同冶炼工艺生产的碳化硼粉末对其陶瓷性能的影响

本文阐述了立式冶炼炉（以下简称A)和卧式冶炼炉(以下简称B)两种冶炼方式冶炼的碳化硼粉未的不同性能，以及利用粉末热压烧结制成的碳化硼陶瓷间性能对比；通过分析和验证，得出影响陶瓷性能的主要因素．得出A冶炼的碳化硼粉末热压烧结的碳化硼陶瓷硬度高，致密性高，其他性能优越于B冶炼的碳化硼粉末热压烧结的碳化硼陶瓷；立式冶炼炉冶炼的碳化硼粉束制得的碳化瑚喷砂嘴使用寿命达800—1000小时以上。     

Study on preparation and fire-retardant mechanism analysis of intumescent flame-retardant coatings

An intumescent flame-retardant coating was prepared by unsaturated polyester resin and epoxy resin as two-component matrix resins, ammonium polyphosphate (APP) as acid source, melamine (Mel) as the blowing agent and pentaerythritol (PER) as carbon agent, expandable graphite as synergistic agent, adding titanium dioxide (TiO₂), solvent and other assistants. Results showed that such a coating had excellent physical-chemical properties. When the thickness of the coating on the wood matrix reached 2.0 mm, the limit of fire-endurance could get to 210 min. And the various component thermal characteristics, decompose processes and interactions of the flame-retardant coating system were investigated by DSC and TGA. The contribution of phosphorus to the formation of the final charring layer and their morphological structures was studied by SEM, XRD and FTIR. On the basis, the flame-retardant mechanism of the intumescent flame-retardant coating was systematically investigated.     

A novel and versatile method for the synthesis of soluble fullerenated polymers

Summary A new route for the preparation of soluble fullerenated polymer through the reaction of carbanion intermediates of polymers with fullerenes, particularly C₆₀, is demonstrated. Confirmation of the covalent attachment of C₆₀ to the polystyrene backbone is by a variety of techniques such as UV-Vis, FT-IR, TGA, SEM and ¹³C NMR etc. The product, which has a visibly brownish yellow cast when compared with the unreacted polymer, is soluble in some common organic solvents. The thermal stability of pure polystyrene is enhanced by C₆₀-chemical modification, and no bonds within the carbon sphere are broken.     

The application of reactive dyes to cotton by a wet-on-wet cold pad-batch method

Cotton ha been dyed with reactive dyes by both wet-on-wet (WOW) and wet-on-dry (WOD) cold pad-batch processes, and by conventional exhaust methods. The colour yields, in terms of the Kubelka-Munk values as a function of the amount of fixed dye, showed that the WOW method required less fixed dye to produce a given depth of shade than the other methods. It is proposed that the higher colour yields are a consequence of limited dye penetration into the cotton fibre. Compared with exhaust dyeings, WOW and WOD dyeings were clearly ring dyed but, unfortunately, no definitive difference in the degree of dye penetration into the cotton fibres was found despite their colour yield differences. Although ring dyeings often have inferior fastness properties, the WOW dyeings were of equal or slightly superior fastness to repeated washing and to normal daylight in comparison with the other dyeings     

Monitoring Damage Evolution in a Titanium Matrix Composite Shaft Under Torsion Loading Using Acoustic Emission

The damage behaviors of a titanium matrix composite shaft under torsion loading were monitored using the acoustic emission technique. The composite shaft with SiC fibers at ± 45° orientations was prepared by the solid-state fabrication process. Both the torsional rigidity and torsional strength of the TMC shaft were improved by SiC fibers. The acoustic emission responses during the loading–unloading–reloading, under quasi-static and cyclic torsion tests were investigated. Multiple acoustic emission signals were grouped as mechanical noise, matrix deformation, interface debonding and fiber fracture using amplitude, waveform shape and frequency centroid parameters. A substantial reduction of signals generated by matrix deformation was found in the reloading test. During the quasi-static torsion test, interface debonding and progressive breaks of SiC fibers occurred. According to different acoustic emission behaviors, the failure process in the torsion fatigue test can be divided into three stages: the initial stage, the fiber fracture stage and the fast fracture stage.     

沥青带水磺化工艺的研究

通过沥青磺化过程的主反应和副反应，进一步讨论了磺化工艺的原理，磺化试剂的选择，溶剂的组成，带水速度，溶剂的回收方式等各种因素对产品质量的影响。     

水煤浆管内流动的相似准数及其阻力特性

在分析水煤浆“滑移层”内流动的基础上,导出了表征水煤浆流动状态的相似准数——广义雷诺数Re_g。结果表明,它不仅适用于管内存在滑移的具有广义宾汉体和宾汉体性质的水煤浆流动,且同样适用于非牛顿流体中的宾汉体、幂律流体以及牛顿流体的无滑移流动。同时,水煤浆虽为液固两相非牛顿流体,但其层流流动的沿程能量损失系数的计算公式类似于牛顿流体的简单形式,即λ=64/Re_g。该式的计算精度令人满意。     

醇、酸类添加剂对脱脂清洗液清洗效果的影响

本文研究了清洗剂浓度、有机醇(R—OH)、无机酸(HA)和HA/R—OH对清洗液清洗效果的影响.结果表明随着清洗剂浓度的增加和R—OH、HA的加入,清洗液的脱脂清洗能力增强.同时给出了R—OH、HA和清洗剂较合适的配比范围.     

Zr-Al-Co块状非晶的成分优化

运用等电子浓度和变电子浓度线判据实现了Zr—Al—Co块状非晶合金的成分优化．在(Al50Co50)-Zr等电子浓度线(e／α=1．5)和(Zr9Co4)—Al及(Zr78．5Co21．5)—Al变电子浓度线上设计成分，并通过吸铸法制备块状合金．实验结果表明，在(Al50Co50)—Zr等电子浓度线和(Zr9Co4)—Al变电子浓度线上可形成块状非晶合金，且非晶合金的热稳定性与非晶形成能力随电子浓度的增大而单调递增．其中，(Al50Co50)-Zr等电子浓度线和(Zr9Co4)—Al变电子浓度线交点处形成的Zr53Al23．5Co23．5非晶合金，具有最大的热稳定性和非晶形成能力，特征热力学参数Tg=783K，Tx=849K，Tg／Tm=0．637，Tg／Ti=0．590。     

高铝锌基合金直齿圆锥齿轮的挤压铸造工艺

利用挤压铸造技术生产高铝锌基合金直齿圆锥齿轮，齿面精度能够得到保证。适用于工作环境较好，载荷不是很大条件下的高铝锌基合金直齿圆锥齿轮，可减少设备投资、减少工序工时，从而大大降低生产成本，具有很高的经济效益和社会效益。