Pd、Ru、Ce溶质对Pt-Pd-Rh合金晶粒长大的影响

用图像仪测定了分别添加Pd、少量Ru、微量Ce的Pt-Pd-Rh合金在900~1200℃退火0.5h的晶粒度.在金相显微镜下观察了上述合金的显微组织,发现在Pt-Pd-Rh合金中Ce添加剂显示了大的晶界偏析和强的抑制晶体长大作用.讨论了Pd、Ru、Ce溶质对Pt-Pd-Rh合金晶粒长大的影响的作用机制.     

螺旋面数控加工方法研究

研究大模数少齿数螺旋转子的数控加工和编程技术.用普通球头铣刀在四轴加工中心上铣削转子的螺旋齿面,采用计算机辅助编制数控加工程序.首先在Pro/E软件中绘出转子的模型,然后通过自行编制程序将转子端面型线即渐开线和摆线离散化,求得刀触点,结合渐开线和摆线的性质,利用微分几何工具计算出该类曲面的法矢,将法矢单位化,得到各点的单位法矢,选择合适的球头铣刀的半径,继而求得刀具中心数据,即刀位点坐标值,按刀位点坐标值编写数控程序.从而实现了在单件小批量生产时此类螺旋转子低成本的加工.     

液态Sn-2.8Ag0.5CuX钎料性能的研究

采用一种新方法制备Sn-2.8Ag0.5CuX亚共晶改性钎料,研究液态钎料的工艺性能。发现原子掺杂能显著改善液态钎料的抗氧化性、润湿性和漫流性,而亚共晶的成分设计既能降低钎料成本,又能延长液态钎料在使用过程中的稳定性。在265℃和大气气氛下,液态钎料表面氧化渣的生成速率仅为0.36mg/cm2·min;当采用RMA-flux钎剂时,t0=0.82s,F3=0.75mN,扩展率接近78%。     

低铝硅铁的生产

分析了硅铁冶炼中Al2O3的还原性和炉外精炼脱铝原理,提出了生产低铝硅铁的有效方法。     

聚酰胺增韧改性研究进展

介绍4类增韧尼龙合金,即聚烯烃、烯烃共聚物、弹性体共混;掺混高性能工程塑料;无机非弹性体增韧和各种尼龙共混材料。对影响增韧改性的各种因素进行了讨论,列举了主要研制工作概况。     

采用烘烤硬化钢板（BH钢）改善汽车车身外表零件的抗凹陷性能

为了减轻汽车自重,节约能耗。国外广泛采用高强度钢板,并研究了采用ＢＨ钢板后对车身外表零件抗凹陷性能的影响。结果表明：ＢＨ钢冲成零件油漆烘干后的屈服强度显著提高。如果零件使用钢板的厚度不变,可以明显地提高其抗凹陷性能;如果减薄钢板厚度（减轻车重）可以保持其抗凹陷性能达到原用钢板的水平,满足使用要求。     

双谱地震子波估计

子波处理是提高地震资料分析的一个重要手段,该技术的关键是地震子波的估计。根据高阶累积量中保留有信号相位信息的性质,给出了一种基于地震信号双谱的子波估计突破了以往对地震子波是最小相位的假设,适应于任意相位的子波,针对不同性质的地震子波,进行了理论计算,结果表明,这一该是可行的。同时也显示了信号高阶谱技术在地震资料子波处理,提高分辨率方面的潜力。     

工程塑料的进展

从聚合工艺、共混、合金化、填充、增强、复合的制备技术等方面,简要论述了今后工程塑料,特别是改性复合型工程塑料的主要发展方向。     

Manufacturing and physical properties of all-polyamide composites

Based on the difference in melting points between polyamide 66 (PA66) fiber and polyamide 6 (PA6) matrix, all-polyamide composites were fabricated under various processing conditions. In these all-polyamide composites, the reinforcement and matrix share the same molecular structure unit (–CONH–(CH₂)₅–). Because of the chemical similarity of the two components, good bonding at the fiber/matrix interface could be expected. Effects of processing temperature and cooling rate on the structure and physical properties of composites were investigated by SEM, DMA, DSC analyses, and static tensile test. Fiber/matrix interface strength benefited from elevated processing temperature. The static tensile results showed that the maximum of tensile strength was observed in the processing temperature range of 225–245 °C. At different cooling rates, crystallization temperature of PA6 in the composites was increased compared to the pure PA6 because of the nucleation effect of PA66 fiber surface to the PA6 matrix. A study of the matrix microstructure in a single fiber-polymer composite gave proof of the transcrystalline growth at the fiber–matrix interface, the reason behind which was the similar chemical compositions and lattice structures between PA6 and PA66.     

An innovative method to improve the electrical conductivity of multi-walled carbon nanotubes filled polyamide 6/polystyrene blends

An innovative method has been successfully developed to improve the electrical conductivity of polyamide 6/polystyrene (PA6/PS) blends in this paper. PA6/PS blends containing multi-walled carbon nanotubes (MWCNTs) are prepared by the radical polymerization of styrene in the presence of ?-caprolactam (CL) and MWCNTs, followed by the in-situ anionic ring-opening polymerization of CL. In the resulted PA6/PS blends, MWCNTs are selectively located at the interface of PA6 and PS. Because the interface of 0.5 and 1.0 wt.% MWCNTs filled blends with PA6/PS weight ratio of 70/30 is continuous, a MWCNTs conductive pathway is formed in these two blends, which results in a decrease of volume resistivity by about 9 orders of magnitude.