淬火工艺对Fe-V-W-Mo合金组织和性能的影响

在测试了Fe-5％V-5％W-5％Mo-5％Cr-3％Nb-2％Co-2％c（Fe-V-W-Mo）合金的临界点和CCT曲线基础上，研究了淬火温度、淬火冷却方式对该合金组织和性能的影响。研究结果表明，Fe-V-W-Mo合金油冷淬火温度低于1025℃。随淬火温度升高硬度升高，超过1050℃，硬度反而降低。雾冷和空冷淬火时，淬火温度对硬度影响结果相似，获得最高硬度的淬火温度高于油冷时的淬火温度。Fe-V-W-Mo合金油冷淬火淬透性最好，雾冷次之，空冷最差，但是油冷和雾冷差别不大。Fe-V-W-Mo合金红硬性和韧性随淬火温度升高而提高，超过1150℃时，韧性反而降低。最后讨论了Fe-V—W—Mo合金在不同淬火冷却条件下组织和性能变化的原因。     

Process optimization of sweet potato pulp‐based biodegradable plastics using response surface methodology

Biodegradable plastics were produced from sweet potato pulp (SPP) and cationic starch (CS) or chitosan composite (CC) by compression molding and their mechanical properties were tested. A universal testing machine, Rockwell hardness tester, and Izod impact tester were used for testing the mechanical properties (flexural strength, Rockwell hardness, and Izod strength) of the plastics. A central composite second‐order design was used to study the effects of temperature, time, and moisture content on the flexural strength, Rockwell hardness, and Izod strength of SPP/CS and SPP/CC blended plastics. The flexural strength, Rockwell hardness, and Izod strength of SPP‐based plastics was 101.1–305.9 kg/cm², R29.0–R96.7, and 0.6–3.0 kg cm cm^?2, respectively. Regression analysis predicted the optimal mechanical properties (flexural strength, Rockwell hardness, and Izod strength) to be attained with a 150–160°C temperature, 15–20‐min reaction time, and 20–23% moisture content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 423–434, 2002     

槽液稳定性好的高硬度丙烯酸阳极电泳涂料的研制

在混合溶剂中加入甲基丙烯酸、各种甲基丙烯酸酯单体以及引发剂AIBN和链转移剂DDM,在85℃下反应合成了丙烯酸树脂。分别研究了不同酸值和羟值的丙烯酸单体、不同Tg的丙烯酸树脂以及各种助溶剂和中和剂对漆膜性能的影响。获得了丙烯酸阳极电泳涂料的最佳配方:丙烯酸共聚树脂的酸值为65 mg KOH/g、羟值为69 mg KOH/g、Tg为20℃,溶剂是体积比为1∶1的丙二醇单甲醚和异丙醇的混合物,中和剂是二乙醇胺。该电泳涂料具有良好的槽液稳定性和起泡消泡性。制得的涂膜外观平整、丰满、光亮,厚度为18~20μm,硬度为5 H,冲击强度为500 N/cm2,附着力为1级,柔韧性为1 mm,耐烟雾实验超过400 h。     

低硬度EPDM/PP热塑性弹性体力学性能的研究

就不同参数的三元乙丙橡胶(EPDM)、酚醛树脂硫化剂用量和催化剂与活化剂质量比对三元乙丙橡胶／聚丙烯(EPDM／PP)热塑性弹性体的力学性能和交联密度的影响进行了研究，结果表明：选择END型高不饱和度、适中乙烯含量、高充油型EPDM是制备低硬度热塑性弹性体的较佳选择；当酚醛树脂用量5-7份，催化剂／活化剂质量比为0．12—0．2时，获得的弹性体综合力学性能最好；比较发现，自制的低硬度热塑性弹性体力学性能已接近或达到国外同类产品水平。     

Self-emulsifiable soybean oil phosphate ester polyols for low-VOC corrosion resistant coatings

A series of soybean oil phosphate ester polyols (SOPEP) was prepared by reaction of fully epoxidized soybean oil with phosphoric acid and simultanoeous hydrolysis in the presence of a polar solvent. The polyols were characterized by determination of acid value, oxirane number, hydroxyl value, molecular weight (GPC), and FTIR spectra. These polyols with varying amounts of acid phosphate groups could be self-emulsified to form aqueous dispersions after neutralization with organic base. These aqueous dispersion showed varying degrees of stability and their appearance ranged from opaque dispersions to translucent to clear solutions. Waterborne coating compositions were prepared using these aqueous dispersions as principal components and their thermally cured film properties were studied. it was found that by careful selection and formulation, SOPEPs can be successfully used for low-VOC waterborne coating formulations. SOPEPs with 3.5% phosphate ester content showed visibly superior corrosion resistance properties.     

空气搅拌对n-Al_2O_3/Ni–P化学复合镀层性能的影响

针对纳米化学复合镀施镀过程中纳米颗粒分散问题,设计并研制了可控制空气流量的搅拌装置,研究了空气搅拌强度对n-Al2O3/Ni–P化学复合镀层性能的影响。结果表明,空气搅拌强化了纳米颗粒在镀层中的分散。搅拌强度为80L/h时,纳米化学复合镀层最致密,为典型的胞状结构,镀层中纳米Al2O3含量达到1.13%,镀层硬度可达628HV,镀层孔隙率等级为9级。极化曲线显示,纳米化学复合镀层的自腐蚀电流(9.963μA/cm2)远远小于Ni–P镀层,具有更优异的耐蚀性。     

高硬度弱酸性氰化亚金钾电铸黄金工艺品的研制

在弱酸性氰化亚金钾电铸溶液中加入少量(0.3～0.6 g/L)氰化钴钾,电铸黄金工艺品的硬度达到155～185 HV,与传统产品相比增加了100 HV.电铸工艺品硬度及黄金成色都采用相关的国际标准测定.实验结果表明,黄金铸件的硬度先随氰化钴钾加入量的增加而提高,当氰化钴钾加入量为0.4 g/L时达最大值,而后趋于稳定;Co3 含量在0.008%～0.03%之间时,黄金产品的成色没有影响;加入钴离子后,产品成品率明显增加到76%～92%.该工艺可以显著提高黄金工艺品的质量与产量,节省黄金原料,具有很高的实用价值.     

含双丙酮丙烯酰胺(DAAM)的水性乳液的制备与性能研究

通过预乳化乳液聚合工艺,合成了含官能团单体双丙酮丙烯酰胺(DAAM)、丙烯酰胺、N-甲基丙烯酰胺(NMA)的自交联丙烯酸酯乳液。实验结果表明,DAAM用量的增加对乳液涂膜的硬度有影响,而涂膜的耐水性随NMA用量增加有显著提高,在DAAM用量为单体含量的2％,NMA用量为单体含量的4％时,涂膜的铅笔划痕硬度达2H,耐水性达96h以上。     

Hardness and Fracture Toughness of SiC-Particle-Reinforced MoSi2 Composites

The indentation technique has been used to evaluate the hardness and fracture toughness of SiC-reinforced MoSi₂ composites made by hot-pressing. It is seen that the toughness increases with increasing indentation crack length (under increasing load) and a probable mechanism responsible for this behavior is described. It is also observed that there is an optimum volume fraction of SiC particles for which the maximum fracture toughness of the composite can be achieved.     

Microhardness studies of PMMA/natural rubber blends

The microhardness, H, of PMMA/natural rubber blends, prepared following the solution method has been investigated by means of the microindentation technique. Hardness changes are correlated with the variation of the glass transition temperature. The influence of temperature and degree of deformation on H were additionally examined. The inclusion of rubber particles in the PMMA matrix is shown to soften the blends. The variation of the micromechanical property at the phase boundary of polymer/rubber particle has been studied. Results reveal that H drastically drops at the interphase. In the case of the drawn materials, the indentation anisotropy (ΔH) is shown to gradually increase with the draw ratio, where ΔH is found to be higher for the PMMA/rubber blend than for the original PMMA. This result is explained by the higher orientation of the PMMA molecules near the periphery of stretched rubber particles. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 205–210, 2004