高温钎料PdCu-Ti在氧化铝陶瓷上的润湿性及界面反应

本文采用座滴法试验研究了合金系统ＰｄＣｕ－Ｔｉ在Ａｌ２Ｏ３上润湿性的变化规律，探讨了界面冶金及结合等行为，运用热力学理论对结果进行了分析，随Ｔｉ含量的增加及Ｐｄ含量的减少润湿角逐渐降低，Ｔｉ的加入使界面发生了一个双重变化；液相侧富氧，钛吸收层的生成及随后的固相侧氧化钛的生成，只有界面上生成一氧化钛，才能有较好的润湿行为和较强的结合力。     

Combustion synthesis of NbC/ZrO2 composites: Influence of Cr additives on the microstructure and mechanical properties

Composites of NbC/ZrO₂ reinforced with different weight ratios of Cr metal were prepared by dynamic compaction combustion from a blend of Nb₂O₅–Zr–Cr powders. Factors controlling the synthesis process, the microstructure, and the mechanical properties of the samples, such as Cr wt% and the compression loads were studied. The samples were characterized by XRD, SEM, porosity, and hardness measurements. The porosity value of the sample with no additives was high and reached 31.6 vol%. A sudden decrease in the sample porosity to 2.4 vol % was noticed for the sample containing 3.0 wt% of Cr. A high-density sample with less than 2.0 vol % porosity and maximum hardness of 1038 HV was produced using 5.0 wt% Cr under 300 MPa compression load. Detailed thermodynamic calculations for the effect of Cr additives on the physicochemical properties of the system were introduced.     

Effect of Cr3C2 on Valence-Electron Structure and Plasticity of Rim Phase in Ti(C,N)-Based Cermets

Based on the empirical electron theory of solids and molecules, the valence-electron structure (VES) of the rim phase in Ti(C,N)-based cermets was calculated, and the relationship between the VES and plasticity was determined. The results indicated that the plasticity of the rim phase in a Ti(C,N)-based cermet could be defined using the sum of the n _a values for the covalent bonds, and that chromium dissolution in the rim phase improved the plasticity of the rim phase. Moreover, a series of experiments showed that adding Cr₂C₃ to a typical Ti(C,N)-based cermet strengthened the interface. Based on those results, a Ti(C,N)-based cermet with added Cr₃C₂ was manufactured; the new cermet had more than twice the transverse rupture strength of a typical cermet.     

Utilizing the autocatalysis of Co to prepare low-cost WC-Co powder for high-performance atmospheric plasma spraying

A novel method of incorporating fluidized bed chemical vapor deposition (FBCVD) with electroless plating was developed to effectively prepare the core-shell structured WC-Co composite powders. The Co nanoparticles decorated on the surface of WC particles by FBCVD acted as active catalysts for the subsequent electroless plating process. The particle size and quantity of the decorated Co particles determined the electroless plating rate but the particle size played more important role. For the conditions tested, the maximum electroless plating rate of 2.34 mg/g/min was obtained by using an optimal FBCVD pretreatment at 750°C for 3 minutes. WC-12Co composite powders with a commercial composition widely used for atmospheric plasma spraying (APS) were efficiently prepared. The composite powders exhibited excellent suitability for APS by forming a homogenous Co-W-C ternary liquid stream. The APS coating is not only well-bonded with the substrate but also consisted of hard nonequilibrium Co₃W₃C and W₂C phases with a uniform distribution. Both remarkably improved the hardness and tribological properties of the APS coating.     

Effect of the sintering temperature on microstructure and properties of Al2O3–Cu–Ni hybrid composites obtained by PPS

In the present research, the influence of sintering temperature on the microstructure and properties of Al₂O₃–Cu–Ni hybrid composites prepared by the Pulse Plasma Sintering (PPS) technique were described. In this research, three temperatures have been selected: 1250°C, 1300°C, and 1350°C. SEM observations were carried out to determine the distribution of the metallic phase in the composite depending on the sintering temperature. The conducted experiments and microscopic observations enabled a better understanding of the phenomena occurring between the ceramic matrix and metallic phase in the obtained materials. The mechanical properties like a hardness and fracture toughness were measured. The technology applied allowed us to obtain ceramic-metal composites with a homogeneous microstructure. It was found that the sintering temperature influences the selected physical and mechanical properties of the composites produced. It was found that samples produced at 1300°C are characterized by the highest relative density and the mechanical properties.     

陶瓷吸塑模具制备的工艺研究

本文研究了一种陶瓷吸塑模具，并着重阐述了陶瓷吸塑模具的材料、性能和特点以及该模具在制备过程中工艺路线和工艺要点。     

陶瓷-金属多层涂层不同温度循环冲击损伤特征与演化规律

目的 探讨环境温度对陶瓷-金属多层涂层冲击损伤的影响,获得不同温度条件下涂层的冲击损伤特征,揭示陶瓷-金属涂层在温度与循环冲击共同作用下的失效机理,为多层涂层的设计和使用提供参考.方法 首先使用可调温度的速度控制型单颗粒循环冲击设备,对陶瓷-金属多层涂层在不同温度(35、200、350、500℃)下进行垂直冲击试验.采...     

陶瓷-金属连接活性钎料的研究与发展

陶瓷-金属活性法连接的关键之一是活性钎料。目前研究最多、公认最好的活性纤料是Ag-Cu-Ti系钎料,研究高温连接性能好的活性钎料是活性法陶瓷-金属连接的发展趋势。国内一些精密陶瓷-金属活性法连接强度已达到世界先进水平,今后应注重应用研究。     

金属陶瓷离合器片的研制开发

试验研究了金属陶瓷离合器片的压制工艺、烧结工艺 ,分析了各工艺参数对离合器片摩擦性能的影响 ,确定离合器片的最佳生产工艺为 :压制压力 2 4 5MPa ,烧结温度 ( 86 0± 1 0 )℃ ,烧结保温压力 1 .4 7～ 1 .96MPa ,烧结保温时间 3h。     

Ti（CN）基金属陶瓷合金化后粘结相中固溶元素的定量测定

研究发现：在８０℃时，用浓盐酸溶解Ｔｉ（ＣＮ）基金属陶瓷粉末，粘结相Ｎｉ中的Ｗ、Ｍｏ、Ｔｉ等固溶元素并不能完全溶解，与文献［３］的报道不符；而在８０℃时，用浓盐酸加硫酸则能完全溶解。按本试验提供的方法，可以定量测定Ｔｉ（ＣＮ）基金属陶瓷的粘结相中的固溶元素，方法简便易行，结果再现性较好。