钢铁常温耐蚀磷化液的研究

研究了复合助剂HN对A3钢磷化膜耐蚀性的影响,确定了磷化温度、溶液pH值和磷化时间等工艺参数,并对磷化液中有无HN助剂时生成的磷化膜的腐蚀电位进行了监测。结果表明:在适当的工艺参数下,在含有助剂HN的磷化液中生成的磷化膜具有更正的腐蚀电位,耐蚀性明显提高,磷化膜耐CuSO4点滴时间超过160s。     

对不同腐蚀环境下涂层的耐腐蚀性研究

通过光泽度、附着力和微观结构三方面的实验结果,对聚脲涂层、聚氨酯涂层、环氧云铁涂层在紫外线加速老化和干湿循环交替作用、5%NaCl溶液浸泡作用下的耐腐蚀性进行分析研究,结果表明:聚脲涂层具有更好的防护作用。     

镀铬层在Na2S溶液中的耐蚀性研究

通过称量法测试了镀铬层在不同温度、不同质量分数Na2S溶液中的腐蚀速率,并采用恒电位极化法研究了镀铬层在Na2S溶液中的电化学行为,分析了各因素对镀铬层腐蚀行为的影响。研究结果表明：镀铬层在Na2S溶液中的腐蚀过程有钝化产生;同一温度条件下,提高浓度可加速镀铬层的钝化。     

镀银层在氯化钠和硫化钠溶液中的耐蚀性研究

通过盐雾腐蚀试验、电化学腐蚀试验和硫化钠腐蚀试验,考察了镀银层在氯化钠和硫化钠溶液中的耐蚀性。结果表明:镀银层盐雾腐蚀前后的微观形貌没有明显的差别,而紫铜盐雾腐蚀前后的微观形貌发生了很大的变化;镀银层的自腐蚀电位为-0.205 V,较紫铜的自腐蚀电位正移了约18 mV;镀银层的自腐蚀电流密度为1.42×10^-7 A/cm²,较紫铜的自腐蚀电流密度降低了一个数量级;镀银层在硫化钠溶液中也具有良好的抗腐蚀能力。     

不同黏度计测试羧甲基纤维素溶液黏度对比研究

利用国产NDJ-1型旋转黏度计、NDJ-79型旋转黏度计和美国Brookfield(LVDV-I+)黏度计测定羧甲基纤维素钠(CMC)的黏度,并进行对比实验研究。结果表明,随着1%或2%CMC黏度的加大,三种黏度计的测定值变化曲线表现为,NDJ-1型黏度计测定值高于B型黏度计,B型黏度计测定值高于NDJ-79型黏度计,NDJ-79型黏度计所测黏度值缓慢增大,与NDJ-1型和B型粘度计相比较,差距越来越大。NDJ-1型与B型黏度计相比较,当测定1%CMC黏度时,1,500 mPa.s(NDJ-1型1%黏度)是两种黏度计测定值拉大的变化点;当测定2%CMC黏度时,2,000 mPa.s(B型2%黏度)是两种黏度计测定值拉开的变化点。B型1%黏度值与NDJ-1型2%黏度值近似呈线形关系。B型1%黏度值和NDJ-79型2%黏度值在B型1%黏度值约为3,500 mPa.s时出现变化点。三种黏度计所测1%或2%CMC黏度值没有一定的对应关系。     

铝铬陶瓷材料抗熔渣腐蚀性的提高

在以前的研究中，发现熔渣中陶瓷材料的腐蚀主要依赖于渣的粘度和陶瓷与熔渣之间的碱性缝隙。本研究是在腐蚀测试的基础上，推荐用渣的粘度和碱性缝隙函数方程来预测陶瓷材料在熔渣中的腐蚀率。Cr2O3-Al2O3陶瓷材料是放在SiO2-CaO-B2O3碱性熔渣中进行测试的。     

高耐蚀性常温磷化工艺研究

碳钢件涂装前处理多采用磷化工艺,但常温磷化膜层较薄,耐蚀性能较差。对常温磷化工艺进行改进,得到高耐蚀性常温磷化工艺。研究发现,常温磷化工序前增加表调步骤能够细化晶粒,磷化工序后增加封闭处理,磷化膜层的致密性和抗蚀能力明显改善,膜层的耐硫酸铜点滴时间提高到60 s。封闭处理不影响涂装后漆膜的附着能力,漆膜的附着力达到0~1级,高耐蚀性常温磷化工艺可以作为涂装前处理技术。     

不同材料波形膨胀节抗应力腐蚀性能研究

对316L、Incology800和AL-6XN这3种材料的波纹管进行了应力腐蚀试验,通过试验结果的对比分析,研究了不同材料波纹管抗应力腐蚀的能力并对波纹管的选材和使用提出了建议.     

不同侵蚀介质作用下高性能混凝土耐腐蚀性研究

采用不同快速腐蚀方法,研究了不同化学侵蚀介质对C40高性能混凝土与C25粉煤灰混凝土抗腐蚀性能的影响。研究结果表明,在不同化学腐蚀介质作用下,混凝土耐化学腐蚀性能也不同,但混凝土抗压强度指标下降均比抗折强度快。一般C40高性能混凝土的抗化学侵蚀比粉煤灰混凝土的略好,但人工海水介质除外。     

基于不同胶凝材料钢筋混凝土耐腐蚀性试验研究

针对混凝土结构中钢筋的锈蚀问题,以普通硅酸盐水泥和镁水泥作为胶凝材料,制作了钢筋裸露和涂有环氧树脂涂层的4种钢筋混凝土试件,将其浸泡在氯盐、硫酸盐及镁盐的耦合溶液中,利用电化学方法得到极化曲线和交流阻抗谱,通过塔菲尔外推法进行非线性最小二乘法拟合计算得到腐蚀电流密度、腐蚀电位、腐蚀速率等相关评价指标来衡量混凝土中钢筋锈蚀情况.结果表明:长期浸泡在耦合盐溶液中,普通硅酸盐水泥和镁水泥钢筋混凝土试件都发生了较严重的腐蚀,普通硅酸盐水泥的抗腐蚀性优于镁水泥;在钢筋表面涂有GHT涂层可极大地降低钢筋的腐蚀速率;镁水泥GHT涂层混凝土试件的抗腐蚀性能劣于硅酸盐GHT涂层混凝土试件但优于硅酸盐裸露钢筋混凝土.     

Corrosion Behavior of Alumina Ceramics in Caustic Alkaline Solutions at High Temperatures

The corrosion rate and changes in the microstructure and fracture strength of alumina ceramics (93.0% Al₂O₃ and 99.5% Al₂O₃) were studied in 0.1 m to 25 m NaOH solutions at 150°C to 200°C, where m = mol/(kg of H₂O). The attack of the caustic alkaline solution started at the grain boundaries. Consequently, the corrosion resistance increased with decreasing SiO₂ content in Al₂O₃ ceramics, and the corrosion resistance of 99.5% pure Al₂O₃ was similar to that of Si₃N₄ ceramics. Since large pits are formed by corrosion, the surface area increased first and the apparent corrosion rate increased with time in the initial stage of the corrosion. The corrosion rate of Al₂O₃ increased linearly with increasing NaOH concentration, and the activation energy was 102 kJ/mol. The fracture strength of corroded Al₂O₃ decreased monotonically as the degree of dissolution of alumina increased.     

铸铁在不同温度浓碱介质中腐蚀行为的研究

本文利用电化学法测定了制碱工业常用的普通灰铸铁在40%N aOH中不同温度时的极化曲线和交流阻抗谱,并借助光学显微镜和扫描电镜分析了腐蚀表面的微观形貌和腐蚀产物。结果表明:随温度的升高,在浓碱40%N aOH溶液中,铸铁的极化曲线右移,阻抗减小,腐蚀程度明显加剧。铸铁的微观腐蚀形貌是典型的均匀腐蚀,且腐蚀首先发生在基体和石墨交界处,并逐渐扩展到基体。     

基于不同涂层的镁水泥钢筋混凝土耐腐蚀性试验研究

针对因钢筋腐蚀而造成镁水泥钢筋混凝土使用寿命较短的问题,制备不同涂层钢筋的镁水泥混凝土试件,通过CS350工作站及其分析软件对不同龄期试件进行测试分析,根据腐蚀电位、腐蚀电流密度、腐蚀速率及涂层电阻等电化学参数,衡量同种涂层钢筋在不同环境下的抗腐蚀性能.结果表明:锌美特涂层在三种环境下均出现低腐蚀现象,且室内自然环境下腐蚀情况最轻、自然水浸泡环境下次之,氯盐浸泡环境下最差.美加力涂层与久美特涂层在三种环境下均未出现腐蚀现象,且室内自然环境下抗腐蚀性能最好、氯盐浸泡环境下次之、自然水浸泡环境下最差;三种环境下涂层钢筋防腐性能均为:久美特涂层钢筋最好、美加力涂层钢筋次之、锌美特涂层钢筋最差;涂层钢筋在不同环境下虽然抗腐蚀性能不同,但涂层技术均可以延长镁水泥钢筋混凝土构件的使用寿命.     

Improvement in Corrosion Resistance of Biomaterial Alumina after 60 keV Nitrogen Ion Implantation

Surface modification of polycrystalline α-alumina is carried out using ion implantation. Samples were implanted at 60 keV N⁺ ions with different ion doses ranging from 1 × 10¹⁵ to 1 × 10¹⁷ ions/cm². Corrosion resistance is studied in a Ringer solution. The increase in corrosion resistance is due to the compound formation studied using Fourier transform infrared spectroscopy and glancing-angle X-ray diffraction techniques. Nanohardness is more at a lower ion dose and decreases at a higher ion dose. Microstrutural investigation shows that the decrease in corrosion resistance and nanohardness at a higher ion dose is due to the damage accumulation at the surface.     

Lath-like Structure of β-Tricalcium Phosphate in Orthopedic Implants

The lath-like β-tricalcium phosphate (β-TCP) in the sintered porous β-TCP implants was revealed by transmission electron microscope (TEM). Samples of sintered porous β-TCP implants were extracted from rabbit tibia after implanted for 1–6 months. Although the majority of sintered β-TCP particles are in a granular shape, the lath-like structures of implants are observed occasionally. The length of laths is on the order of 1 μm, while the thickness of laths is on the order of 10 nm. The X-ray energy dispersive spectroscopy and the electron diffraction indicate that the lath-like material is β-TCP with its rhombohedral (     ) plane parallel to the longitudinal direction of laths. High resolution TEM imaging also confirms the finding of electron diffraction. This abnormal morphology of β-TCP have raised our attention, even though its formation mechanism and effects on osseointegration is not yet certain.     

2219铝合金在N_2O_4溶液中的耐蚀性能

本文对不同表面状态的2219铝合金进行了N_2O_4溶液浸泡加速耐蚀性试验,采用微观形貌观测、称重法、电感耦合等离子体光谱等表征手段,对铝合金及N_2O_4溶液在浸泡实验中的变化情况进行了研究分析,从而获得了航天航空产品贮箱长期加注推进剂内壁的防护方案。结果表明,未做表面处理及进行阳极化重铬酸钾填充处理的2219铝合金在N_2O_4溶液介质中的耐蚀性最佳。因此可根据贮箱加注前的存放时间及环境情况,选择作为长储贮箱内壁的防护方案。     

化学镀Ni-Cu-P合金镀层耐蚀性研究

采用极化曲线和交流阻抗法,与Ni-P合金镀层对比,研究了化学镀Ni-Cu-P合金镀层在3.5%NaCl水溶液中的电化学行为。极化曲线结果表明,化学镀Ni-Cu-P合金镀层的自腐蚀电流密度(4.037μA/cm2)远远小于Ni-P合金镀层,说明Ni-Cu-P合金镀层的耐蚀性能比Ni-P合金镀层好。在交流阻抗谱图中,化学镀Ni-Cu-P合金镀层在整个浸泡过程中仅出现一个时间常数的单容抗弧,镀层电阻不断的增大,表明镀层有钝化膜不断生成。     

Corrosion of Alumina in Aqueous Hydrofluoric Acid

A variety of alumina-based ceramics were evaluated for dissolution in an azeotropic aqueous hydrofluoric acid test protocol at temperatures up to 200°C. Weight change measurements and microstructure analysis showed that HF corrosion in polycrystalline aluminas generally occurred at grain boundaries by the dissolution of silicate-based, glass grain boundary films that segregate to grain boundaries. These materials often have useful service lifetimes even though thermodynamic calculations indicate high solubilities. It is proposed that corrosion rates are controlled by chemical reactions at the solid/liquid interface, the physical structure of the solid, and microstructure. The addition of MgO to alumina greatly increased corrosion resistance by removing silicate-based glassy grain boundary films.     

Fracture Resistance Behavior of Silicon Carbide Whisker-Reinforced Alumina Composites with Different Porosities

Fracture resistance behavior was characterized for SiC-whisker-reinforced alumina composites with porosities ranging from 0.6% to 11.5% The composites were hot-pressed from an Al₂O₃ powder with 25 wt% SiC whiskers. Strengths of individual specimens were measured in four-point flexure either for natural flaws or for Vickers-indentation flaws as a function of radial crack size. Indentation crack sizes were controlled with indentation loads which varied between 2 and 200 N. A novel method of analysis of these measurements indicates that the fracture resistance of these composites increases as a function of crack extension, a rising R curve. This behavior is interpreted in terms of tractions from both crack-bridging whiskers and interlocking grains, which develop in the wake of the crack tip as it extends. A decrease in porosity raises the level of fracture resistance, but has a negligible effect on the relative steepness of the R curve. The sizes of natural flaws which causes failure in flexure testing were also estimated from analysis of the data.     

化学镀Ni-P-金刚石复合镀层耐蚀性的研究

研究了次磷酸钠的质量浓度对Ni-P-金刚石复合镀层的成分及耐蚀性的影响。结果表明:镀层中磷的质量分数随次磷酸钠的质量浓度的增加而增加;随着磷的质量分数的增加,镀层组织逐渐由晶态向非晶态转变,自腐蚀电位逐渐正移;高磷镀层可对基体起到更好的保护作用。