焊接热循环对瓷釉涂层管道瓷层/金属界面的影响

采用焊接热模拟、电子探针、金相显微镜、X射线衍射等方法研究了热循环对瓷釉涂层管道瓷层/金属密着性的影响.结果表明:焊接热循环改变了瓷层的相结构,峰值温度低于1200℃的试样,瓷层相结构主要为玻璃态,有少量晶相析出,峰温为1350℃的试样,瓷层冷却后全部转变为玻璃态;焊接热循环对瓷层与金属界面产生了显著的影响,不同温度区间发生了不同的变化,950℃时瓷层与基体之间元素过渡平缓,密着最好,而1350℃时由于过渡层的烧损,使瓷层与基体金属之间的连接变得异常脆弱,从而出现了热影响区由高温区到低温区密着性能由差到好,再到一般的变化趋势.瓷层/金属界面过渡层的存在至关重要,各元素在界面处的平缓过渡有利于提高瓷层与金属基体结合性能,界面层的消失,会使其密着性能恶化.     

用分形理论研究低渗储层孔隙结构

储集层岩石的孔隙结构非均质性对于油气的渗流规律以及水驱油效率都具有重要的影响。利用分形理论对孔隙结构的非均质性进行研究。结果表明,分形维数不同孔隙结构不同,所研究的储集层具有单一分形（分形维数2.690 7～2.814 0）和分段分形特征（分形维数2.414 8～2.995 2）;以分形维数为基础,可以根据孔喉渗透率贡献判断孔隙结构的非均质性和复杂程度。     

石墨基浸金属多孔材料微观孔隙结构及其分形特征

为定量描述石墨基浸渍金属材料的孔隙结构特征并研究其对浸渍过程的影响规律,在石墨基多孔材料孔隙形成机理研究的基础上,分析形成浸不透孔洞的原因,并运用分形理论对孔隙结构特征进行了描述. 研究表明,石墨基浸渍金属多孔材料的孔隙结构具有典型的分形特征,其基体、孔隙、浸渍金属分形维数分别为1.80~1.85, 1.55~1.65, 1.50~1.55,未浸渍区域的分形维数为1.42~1.60,孔隙率为17.25%~24.85%. 分形维数反映了孔隙结构的非均质性,与采用压汞实验获得的孔隙率变化规律有较好的一致性,证明可用分形维数表征石墨基浸金属材料的孔隙率.     

分形理论及其在无机材料烧结与氧化过程中的应用

本文以科赫曲线与康托尔三分点集为例,讨论了有规分形维数的计算;以科赫曲线在垂直方向的两种拓展为例,讨论了有规分形维数的加和性;以周长-面积法、变量法、网络法与半径法为例,介绍了无规分形维数的计算方法.提取了材料烧结界面与氧化界面的分形图形,并利用FDCP(Fractal Dimension Calculation Programme)对其分形维数进行了计算.探讨了分形理论在材料烧结与氧化过程中的应用.     

喷釉管道釉层密着性的研究

用热震试验，落球试验，扫描电镜，Ｘ射线衍射等对喷釉和道釉层密着性进行了研究。结果表明，用氧气－石油天然气火焰在碳钢管里表面热喷玻璃釉料可以获得均匀，无裂纹，密着良好的釉层。釉层表面相结构 主要为玻璃态，有少量日 想Ｎａ２Ｍｏｏ４（ｍＯｏ３）ｙ析出；氮气保护可以提高釉层的抗热震性，耐冲击性及金属与瓷层界面的致密性；金属与釉层界面之间１０μｍ范围内形成了界面过渡区，对釉层密着有重要影响。     

转炉钢渣粉粒度分布的分形特征

采用Mastersizer2000激光衍射粒度分析仪对球磨转炉钢渣粉粒度分布进行了测试,运用分形几何理论分析了钢渣粉的分形维数,探讨了分形维数与球磨时间、比表面积、特征粒径、均匀性系数及胶砂性能之间的关系.结果显示:球磨转炉钢渣粉粒度分布具有分形特征;分形维数在2.2～2.5之间,其值大小反映了钢渣粉的细度和分布宽度;分形维数越大,钢渣粉越细,粒度分布越宽;分形维数与球磨时间、比表面积、特征粒径、均匀性系数以及胶砂(w(标准水泥)∶w(钢渣)=70∶30)流动度之间存在良好的线性相关,相关系数在0.95～1之间.在本实验条件下,存在一个最佳分形维数2.41,在此分形维数下砂浆各龄期抗压强度最高.     

重介质旋流器分选效果与入选原煤粒度组成的关系研究

介绍了分形维数的概念,采用分形维数表征原煤的粒度组成,实例研究表明,重介质旋流器分选效果与原煤粒度组成即分形维数之间存在着明显的线性关系,粒度组成越细,分形维数越大,分选效果越差,可能偏差越大。     

基于分形理论的玄武岩筋废旧钢纤维混凝土梁受弯性能研究

为了利用梁表面裂缝的分布和演化过程来研究玄武岩筋废旧钢纤维混凝土梁的受弯性能,对6根不同废旧钢纤维(Recycled Steel Fiber,RSF)体积掺量和配筋率的试验梁进行受弯试验,并运用分形理论对梁表面裂缝进行分析.验证了玄武岩筋废旧钢纤维混凝土梁表面裂缝分布的分形特征,其分形维数在0.89～1.07之间.探讨了梁表面裂缝分形维数与荷载等级、RSF体积掺量、配筋率及跨中挠度之间的关系.结果表明:分形维数与荷载等级和跨中挠度均呈对数增长关系;极限状态下,RSF的掺入减小了梁表面裂缝的分形维数,RSF体积掺量为1.5％ 时,分形维数最小为0.9722;随着配筋率的增加,梁表面裂缝发展更充分,其分形维数也更大.     

镇泾油田延9储层岩石孔隙结构的分形研究

储层岩石的孔隙空间具有良好的分形特征,孔隙结构的分形维数可以定量描述孔隙结构的复杂程度和非均质性。本文应用分形几何原理,对镇泾油田延9低渗透储层岩石的孔隙结构进行了研究。得出储层砂岩孔隙分形维数同孔隙半径呈良好的对数关系。认为孔隙结构分形维数越大,孔隙结构的复杂程度越强,非均质性越强,储集性能越差,反之亦然。     

中孔纯硅分子筛的表面分形结构表征

采用计盒维数方法对中孔纯硅分子筛的结构进行了分形研究.结果表明:所研究的多孔分子筛结构存在分形现象.根据计算,室温晶化(25℃)和水热晶化(125℃)工艺所得到的产物分形维数分别为2.56和2.61,高于典型活性炭的分形维数2.21;而且3个样品的分形维数与其BET低温氮吸附法测试的比表面积变化趋势一致.因此,对多孔材料表面进行分形表征可与其表面性质相联系.     

玻璃涂层与碳钢基材结合性能及界面分形研究

采用热熔敷法在碳钢基体上制备了玻璃涂层,用落球冲击试验研究了熔敷温度对玻璃涂层与碳钢基体结合性的影响,并利用金相显微镜和扫描电镜分析了涂层与基体的界面形貌,计算了界面形貌曲线的分形维数.结果表明,熔敷温度、界面形貌及其分雏值与结合性存在对应关系.在试验温度范围内,熔敷温度越高,涂层与基体的界面形貌越复杂,其分维值越大,涂层与基体的结合性也越好.     

Exploring the hindering mechanism of element Ti on the adherence of CoO-bearing one-coat enamel/steel

The effect of element Ti on adherence between a CoO-bearing single-layer enamel coating and steel was investigated. Falling-weights tests were carried out and cross-sections at interface of the enamel/substrate were analyzed with a scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). Results show that addition of TiO₂ reduced adherence of the enamel coating by hindering the formation of anchor-like alloy precipitates. The decrease of anchor points lies in the following three reasons: I. The diffusion path of Co²⁺ ions to the interface was lengthened because of the blocking effect of rutile and the FeTiO₃ crystals; II. Formation of CoTiO₃ crystals leads to a reduction of free Co²⁺ ions; III. Co–Fe precipitates form away from the enamel/substrate interface, as FeTiO₃ crystals provide extra surface for the nucleation of Fe–Co alloy precipitates.     

一次搪耐酸搪瓷界面过渡层结构研究

采用合理配方设计,使用一次涂搪工艺,制备出了同时具有优良密着性能和耐酸性能的搪瓷板。采用扫描电子显微镜和能谱仪对一次搪耐酸搪瓷板界面显微结构和元素进行分析,研究结果表明,密着性能优良的一次搪耐酸搪瓷界面呈现咬合齿轮状,元素分析表明瓷层元素和金属元素相互扩散,相互渗透,在性能上表现为密着强度优良。     

覆铝钢板搪瓷密着机理研究

通过对覆铝钢板搪瓷界面形貌、结构、元素分布等的分析 ,从化学反应动力学、热力学以及界面能探讨了密着机理 ,本质是界面化学反应产生络合物、氧化物以及合金相 ,并溶解在界面区瓷釉中 ,在界面形成的化学键使瓷层与基体紧密结合在一起     

Effect of process temperature on the microstructures and properties of enamels coated on Ti-bearing substrate RT360

In this paper, we describe the experimental processing treatment of the enamel coating on Ti-bearing substrate RT360. The experiment simulates the process of manufacturing the enamel heat sink for use in a heat exchanger in nuclear power stations. The effect of processing temperature on the microstructures and properties of the enamel coating was investigated using a scanning electron microscope, X-ray diffraction, transmission electron microscope and other methodologies. Our research determined that the density of Ti (C, N) particles in RT360 substrate was maximized, due to the interaction between the precipitate and solid solution, when processing treatment was at 850 °C. At that temperature, the precipitate density optimized the hydrogen trapping sites, preventing the enamel coating from fish-scaling. Small Fe-rich islands were precipitated in the steel-enamel interface, forming anchor points due to Marangoni convection. Once the processing temperature exceeded 850 °C, sufficient anchor points were created, resulting in a good adherence interface. However, when processing treatment temperature reached 900 °C, excessive liquidity of the molten frit powders resulted in a nonuniform coating. We concluded that processing treatment of enamel-RT360 composite substrate at a temperature of 850 °C was optimum for improved coating of the heat sink.     

异氰酸酯底胶对压敏胶粘接性能的影响

了异氰酸酯底胶对于提高压敏胶粘接性能的影响，分别以单面和双面压敏胶带与钢、铝、铜、玻璃试片粘接，制备了剥离试样和拉剪试样，并分别测试了性能。结果发现，对于两种试样，异氰酸酯 胶均可大幅提高其粘接强度，适当延长涂底胶后的晾置时间，以及贴合后的放置时间有利于粘接性能的提高。     

活性焦液相再生及分形特征研究

分别利用自来水、氨水、NaHCO3和NaOH等4种液相介质对内蒙活性焦进行再生实验研究,并通过活性焦分形特征研究,分析活性焦分形维数与脱硫效果的关系。研究结果表明,自来水与弱碱溶液的再生存在再生速率慢,脱附率不高等缺点,利用强碱如NaOH不仅可以加快脱附速率,而且脱附完全度高达97％以上;活性焦具有分形几何的特征,其分形维数与脱硫趋势存在一定的联系。     

Microalloy Precipitation at the Glass–Steel Interface Enabling Adherence of Porcelain Enamel

The adherence of vitreous enamels on steel plates is studied clarifying the mechanisms taking place at the interface during firing. Evidence is provided from electron microprobe analysis for an iron alloy precipitation at the interface, which results from oversaturation of ferrous iron in the enamel glass. Subsequent coalescence of the alloy particles is observed but only after their bonding to the base metal adherence after cupping is achieved. The formation of microalloys requires Co²⁺, Ni²⁺, and Cu²⁺ ions in the enamel glass. A selective dissolution of the base metal by the latter cations does not occur.     

Nature of Adherence of Porcelain Enamels to Metals

An investigation of the fundamentals of the adherence of porcelain enamels to metals indicated that good adherence is the result of metal-to-metal bonds between the atoms in the base metal and the proper metallic ions in the enamel. To accomplish this type of bond, the enamel must meet certain chemical and thermodynamic requirements: (1) The enamel at the interface must be saturated with an oxide of the metal and (2) this oxide must be one which, when in solution in the glass, will not be reduced by the metal. In the case of iron, the oxide is FeO. Many of the phenomena observed in commercial enameling were investigated and found to be related to adherence, but not essential for its development. An example is the precipitation of metallic particles in the enamel. Much of the complexity in commercial enameling arises from the limitations imposed by practical considerations. For example, because enamels usually are fired in air, the heavy scale developed during the early stages of firing must be removed before adherence can be developed. Likewise, as the conditions of the enamel-metal interface change rapidly during firing, "adherence-promoting oxides" are used to help maintain the necessary conditions for the time required in commercial enameling. Surface roughness, although not necessary for excellent adherence, was found to improve the apparent adherence when the bond between the enamel and the metal was relatively weak.