退火处理对Ni-Al纳米复合镀层循环氧化性能的影响

研究在500℃真空扩散不同时间条件下的扩散合金化对Ni-Al纳米复合镀层的结构与抗循环氧化性能的影响。结果表明：扩散不仅导致Ni-Al纳米复合镀层的基体Ni晶粒粗化,还导致Al固溶在基体Ni中,Ni与Al之间形成金属化合物;随着扩散合金化时间的延长,Ni-Al合金涂层中的空洞减少,从而减少了合金涂层在循环氧化过程中出现的穿透性裂纹和内氧化,抑制了氧化膜剥落区瘤状NiO的形成,提高了Ni-Al合金涂层的抗循环氧化性能。     

卫北三叠系砂岩裂缝油藏压裂工艺技术研究与应用

卫北三叠系砂岩裂缝型油藏由于天然裂缝的存在,压裂液大量滤失,增加了施工的砂堵几率和对储层的伤害。通过压裂液、压裂工艺技术研究,解决了砂岩裂缝性储层压裂施工易砂堵和储层污染问题,形成了一套以降滤失为主,适合于砂岩裂缝型油气藏的压裂工艺技术。并经过现场实施,取得了显著的增产效果。     

稀土Y对Ti50Ni50形状记忆合金700℃下恒温氧化行为的影响

本文研究了添加Y对等原子比TiNi形状记忆合金显微组织和700℃恒温氧化行为的影响。结果表明加入稀土Y细化了TiNi合金的晶粒尺寸。Y含量为0.5和1%时Y的加入显著降低了Ti-Ni合金的氧化速率。然而当Y含量为5at%时,含Y的Ti-Ni合金的氧化速率增大     

页岩储层中同步压裂形成复杂缝网可行性研究

同步压裂能够更好地利用2个井筒中裂缝诱导应力干扰,降低地应力差异系数,使页岩油气藏产生更加复杂的裂缝形态。文中运用位移不连续理论,建立了二维平面裂缝诱导应力场数学模型,讨论了页岩储层形成复杂缝网所需要的地应力条件,分析了裂缝净压力、裂缝参数和原地应力场等因素对同步压裂形成裂缝网络复杂程度的影响规律。结果表明,裂缝净压力越大、裂缝长度越长、原地应力差异越小,页岩储层形成复杂缝网的可行性越大。研究结果对判断我国页岩油气藏能否应用同步压裂形成复杂缝网具有一定的理论指导意义。     

溅射Ni16Co26Cr10Al纳米晶涂层的熔盐热腐蚀性能

利用磁控溅射技术在铸造Ni16Co26Cr10Al合金上溅射了相同成份的纳米晶涂层,以研究晶粒化对高温合金抗高温腐蚀性能的影响.热腐蚀试验在900℃的75%Na2SO4 25%NaCl(质量分数)混合熔盐中进行.结果表明溅射Ni16Co26Cr10Al纳米品涂层由于品粒尺寸细小,促进了保护性氧化物形成元素Al向氧化前沿的扩散,从而促进了保护性Al2O3的快速形成,使得溅射Ni16Co26Cr10Al纳米晶涂层表现出比M38合金更优异的抗热腐蚀性能.     

Cr颗粒尺寸对Ni-Cr复合镀层750℃热腐蚀性能影响

采用复合电镀技术,通过向普通电镀溶液中分别加入平均粒度为40 nm和1~5μm的Cr粉的方法在Ni基材上制备了一种金属Ni基纳米Cr粒子弥散的Ni-Cr纳米复合镀层和一种微米Cr粒子弥散的Ni-Cr复合镀层。混合盐(75 wt%Na2SO4+25wt%NaCl)750℃热腐蚀行为结果表明:与微米Cr粒子弥散的Ni-12.4 wt%Cr复合镀层相比,Ni-11wt%Cr纳米复合镀层表现出更好的耐腐蚀性能。SEM/EDAX、XRD和TEM分析表明,在相同的Cr颗粒含量条件下,Cr颗粒尺寸的降低提高了Ni-Cr复合镀层的抗腐蚀性能,这是因为Cr颗粒尺寸的降低和基体Ni晶粒的细化增加了单位面积内的Cr2O3形核率,缩短不同Cr2O3核间的距离,与此同时基体Ni晶粒的细化有利于保护性氧化物形成元素Cr沿晶界向腐蚀前沿的快速扩散,从而加速了保护性Cr2O3膜的快速形成。     

Effect of Y2O3 on microstructure and oxidation of chromizing coating

A Y2O3-modified chromizing coating was produced by chromizing an as-electrodeposited Ni-Y2O3 composite film using pack cementation method at 1 100 ℃ for 3 h. For comparison, chromizing was also performed under the same condition on an asdeposited Ni film without Y2O3 particles. Oxidation at 900 ℃ for 120 h indicates that although on both two chromizing coatings chromia scales grow during oxidation, the Y2O3-modified chromizing coating exhibits an increased oxidation resistance due to the formation of thinner, denser and finer-grain scale. The effect of Y2O3 on the coating formation and the coating oxidation behavior was discussed in detail.     

Sliding wear behaviors of electrodeposited Ni composite coatings containing micrometer and nanometer Cr particles

Micrometer and nanometer Cr particles were co-deposited with Ni by electroplating from a nickel sulfate bath containing a certain content of Cr particles. Cr microparticles are in a size range of 1-5 (m and Cr nanoparticles have an average size of 40 nm. The friction and the wear performance of the co-deposited Ni-Cr composite coatings were comparatively evaluated by sliding against Si3N4 ceramic balls under non-lubricated conditions. It is found that the incorporation of Cr particles enhances the microhardness and wear resistance of Ni coatings. The wear resistance of Ni composite coating containing Cr nanoparticles is higher than that of the Ni composite coating containing Cr microparticles with a comparable Cr particle content. The co-deposition of smaller nanometer Cr particles with Ni effectively reduces the size of Ni crystals and significantly increases the hardness of the composite coatings due to grain-refinement strengthening and dispersion-strengthening, resulting in a significant improvement of wear resistance of the Ni-Cr nanocomposite coatings.     

Oxidation ofAl2O3-dispersion chromizing coating by pack-cementation at 800 ℃

Preparation and oxidation of an Al2O3-dispersed chromizing coating were investigated by chromizing an aselectrodeposited Ni-Al2O3 nanocomposite film using a conventional pack-cementation method at a greatly decreased temperature （800 ℃）. For comparison, chromizing was also performed with the same condition on an as-deposited Ni film without Al2O3 nanoparticles. Oxidation at 900 ℃ indicates that, compared with the Al2O3-free chromizing coating, the Al2O3-dispersed chromizing coating exhibits a increased oxidation resistance, due to the formation of purer and denser chromia scale. The effect of Al2O3 on the coating formation and the coating oxidation behavior was discussed in details.     

化学镀Ni-P-CNTs-纳米SiC复合镀层的摩擦学行为

采用化学共沉积方法制备了Ni-P-CNTs-纳米SiC复合镀层，并研究了其复合镀层的摩擦学行为。结果表明：与在相同参数下制备的Ni-P，Ni-P-SiC，Ni-P-CNTs，Ni—P—CNTs-微米SiC复合镀层相比，Ni—P—CNTs-纳米SiC复合镀层表现出最低的摩擦系数与最好的耐磨性。