天然帽用草纤维的形态结构及EDS能谱分析

对蓆草、棕丝草、琅琊草、咸草、蒲草等5种帽用草纤维用扫描电镜观察其表面形态和截面结构,发现帽用纤维表面存在大量的气孔和沟槽,测量出气孔的长度20-73μm,宽度8-33μm。截面有较大的空隙,纤维空隙的大小依次是棕丝草、蒲草、琅琊草、蓆草、咸草。对其表面选取微区进行EDS能谱分析,结果表明5种帽用草纤维都含有C、O、Al,且C、O元素的含量都在96.99%以上,其他如Si、Na、Mg、Cl、P等属于微量元素,属纤维素纤维。     

华池—南梁油田长8油藏高阻水层解释方法

鄂尔多斯盆地华池—南梁油田长8油藏存在高阻水层,油水层对比度低,油层识别难度大。为提高油层判识率,以大量测井、录井资料和岩石物理实验为基础,确定油藏水层高阻的主控因素。根据不同类型高阻水层测井响应特征,利用中子、密度和声波时差测井数据,评价孔隙结构,识别复杂孔隙结构型高阻水层;利用中子—密度曲线交会特征进行电性因子校正,扩大油水流体特征,有效识别复杂润湿型高阻水层。通过对不同主控因素高阻水层测井响应特征研究,采用相应测井技术方法有效识别,提高图版油水特征值的准确度和测井解释符合率。     

柴达木盆地涩北地区第四系泥岩型生物气储层孔隙有效性评价

通过低场核磁共振实验分析了柴达木盆地涩北地区第四系泥岩型生物气储层在饱和水状态及渐变烘干温度状态下的T₂谱,明确了孔隙流体的核磁响应特征,以评价孔隙的有效性。研究结果表明： ①核磁共振实验是以饱和水状态T₂谱为基础,采用正态分布函数拟合构建了离心束缚水T₂谱,确定了可动流体和毛管束缚流体T₂截止值,用于划分出流体类型并开展了孔隙有效性评价。②研究区岩样饱和水状态T₂谱谱峰呈左小右大的形态,右峰幅度值远大于左峰,占T₂谱幅度值90%以上;随着烘干温度的升高,T₂谱幅度减小且左移趋势明显;束缚水T₂谱形态近似于正态分布,起始位置与饱和水状态的T₂谱基本重合。③研究区可动流体T₂截止值T_{2 C1}平均为3.3 ms,毛管束缚流体T₂截止值T_{2 C2}平均为1.8 ms;孔隙流体包括可动水、毛管束缚水和黏土束缚水,黏土束缚水T₂小于T_{2 C2},毛管束缚水T₂大于T_{2 C2}且小于T_{2 C1},可动流体T₂大于T_{2 C1};毛管束缚水含量最高,黏土束缚水其次,两者占总孔隙流体的84.43%～95.06%,可动水含量低。④研究区储层有效孔隙占总孔隙的54.99%,主要为毛管束缚孔,黏土束缚孔为无效孔隙;黏土含量越高,有效孔隙度越小。     

聚乳酸/聚氨酯复合多孔材料制备及吸油性能研究

以聚乳酸（PLA）为基体,添加不同含量聚氨酯（TPU）熔融共混制备具有不同相形态的PLA/TPU共混物,基于超临界二氧化碳（scCO₂）微孔发泡工艺,研究不同发泡温度下PLA/TPU复合多孔材料泡孔结构、发泡倍率和开孔率对样品吸油性能的影响。结果表明,随着TPU含量从10 %（质量分数,下同）增加到50 %,共混物从典型的“海?岛”相形态转变为部分共连续相形态,PLA基体黏弹性提升,结晶能力下降;PLA70组分发泡后泡孔结构更为均匀,随着发泡温度的增加,泡孔尺寸和发泡倍率先增大后减小,在94 ℃发泡温度下发泡样品发泡倍率达到29.1倍,最大开孔率75 %;TPU的加入显著增加了PLA基体的弹性回复能力,94 ℃发泡温度下的发泡样品具有最大的抗压强度,永久形变量最小;针对硅油和环己烷的吸油测试发现对硅油的吸油量大于环己烷,发泡材料的吸油量与发泡倍率和开孔率的乘积成正比,针对硅油单次最大吸油量为10.4 g/g。     

Oxidation behavior of TiAl coated with a fine-grain Co-30Cr-4Al film

The oxidation behavior of TiAl coupons coated with a fine-grain Co-30Cr-4Al (mass %) film of about 30-m thickness has been studied at 1100–1400 K in a flow of purified oxygen at atmospheric pressure for up to 500 ks. Three oxidation stages were recognized: initial transient, parabolic, and accelerated stages. However, at 1100 K a parabolic stage continues for more than 800 ks. The activation energy for parabolic oxidation agrees with reported values for the oxidation of alumina-former alloys, although the mass gains during the parabolic stages are relatively small at 1200 and 1300 K. Micropores developed mainly at the scale/coating and coating/substrate interfaces as oxidation proceeded. This is attributable to recrystallization of the coating during oxidation and a Kirkendall effect due to preferential diffusion of Co into the substrate. The accelerated oxidation can be explained in terms of the formation of rutile mounds on the scale.     

FeAl/FeAlSi非对称膜材料的制备及膜基结合性能

目的制备高温腐蚀环境下应用的Fe Al/Fe Al Si非对称膜材料,研究膜与基体的结合性能。方法采用粉末反应合成法制备大孔径、高孔隙度的FeAlSi多孔体作为支撑体,通过浸渍法在支撑体表面制备小孔径的FeAl涂层作为膜层,再经烧结得到Fe Al/Fe Al Si非对称膜材料。研究Fe Al/Fe Al Si非对称膜材料的孔结构性能及膜基结合性能。采用XRD和SEM研究多孔膜材料的物相组成及微观形貌,采用孔结构测试仪及压汞法测试支撑体与膜层的孔结构参数,采用拉伸法和反吹实验研究Fe Al/Fe Al Si非对称膜材料的膜基结合性能。结果 Fe Al/Fe Al Si非对称膜材料表面膜层均匀、完整,膜层与支撑体之间具有冶金结合。支撑体的孔隙度和平均孔径分别为43.0%和22.7μm,膜层的孔隙度和平均孔径分别为36.5%和7.5μm。当膜层厚度增加时,膜材料的透气度下降,最大孔径在一定膜层厚度范围内变化不大,当膜层厚度在150～300μm范围内时,最大孔径约为7.8μm。膜层与支撑体的结合强度大于5.5 MPa。结论浸渍法制备的Fe Al/Fe Al Si非对称膜材料的孔结构性能优异,膜基结合性能满足工业应用。     

烧结材料孔隙形态与分布对离子氮碳共渗层组织结构的影响

研究了烧结材料孔隙形态与分布对离子氮碳共渗层组织结构的影响。试验表明，随试样孔隙数量的增加，γ＇相含量和扩散层深度增加。由于试样的正压制面与侧压制面的孔隙形态及分布不同，导致化合物层深度和相组成不同。还观察讨论了氮原子在氮碳共渗层的分布状态。     

AZ31镁合金钨极交流氩弧焊焊缝气孔的研究

采用金相显微镜和扫描电镜对AZ31镁合金薄板在钨极交流氩弧焊时产生的气孔进行了研究,分析了气孔的形成原因,并提出了焊缝气孔的防止措施.试验结果表明:焊前彻底清除母材坡口、表面和焊丝表面的油污及氧化膜,采用较大的焊接电流和较高的焊接速度,选用合适的氩气流量,焊前预热等措施都能有效地防止焊缝中气孔的产生.     

Exploring thermal spray gray alumina coating pore network architecture by combining stereological protocols and impedance electrochemical spectroscopy

Complex multiscale pore network architecture characterized by multimodal pore size distribution and connectivity develops during the manufacture of ceramic thermal spray coatings from intra- and interlamellar cracks generated when each lamella spreads and solidifies to globular pores resulting from lamella stacking defects. This network significantly affects the coating properties and their in-service behaviors. De Hoff stereological analysis permits quantification of the three-dimensional (3D) distribution of spheroids (i.e., pores) from the determination of their two-dimensional (2D) distribution estimated by image analysis when analyzing the coating structure from a polished plane. Electrochemical impedance spectroscopy electrochemically examines a material surface by frequency variable current and potential and analyzes the complex impedance. When a coating covers the material surface, the electrolyte percolates through the more or less connected pore network to locally passivate the substrate. The resistive and capacitive characteristics of the equivalent electrical circuit will depend upon the connected pore network architecture. Both protocols were implemented to quantify thermal spray coating structures. Al₂O₃-13TiO₂ coatings were atmospherically plasma sprayed using several sets of power parameters, are current intensity, plasma gas total flow rate, and plasma gas composition in order to determine their effects on pore network architecture. Particle characteristics upon impact, especially their related dimensionless numbers, such as Reynolds, Weber, and Sommerfeld criteria, were also determined. Analyses permitted identification of (a) the major effects of power parameters upon pore architecture and (b) the related formation mechanisms. This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials Park, OH, 2006.     

硬质合金大规格顶锤成型工艺的研究

研究了压制成形过程硬质合金顶锤的制备工艺及工艺参数影响抗断裂强度的规律性,分析了冷等静压可得到理想压坯密度的理论基础。提出了大制品成型方法。