α-Al_2O_3对瓷坯抗弯强度影响的研究

本文研究了 α- Al2 O3粉替代石英以及添加 Mg CO3、Ti O2 和 Cr2 O3对瓷坯抗弯强度的影响。并采用 XRD和 SEM手段 ,研究了瓷坯显微结构的变化及其与抗弯强度的关系。研究结果表明 :α- Al2 O3替代石英瓷坯抗弯强度得到明显改善 ;添加适量的矿化剂可以使瓷坯强度进一步得到提高 ,并且能降低烧结温度。     

注凝成型及其烧结工艺研究进展

科技的发展对材料的要求越来越高，传统的成型和烧结技术仅适用于小尺寸且形状规则的金属成型，且需要在一定的压力下才能达到足够高的力学性能。注凝成型技术适用于各种复杂形状、大尺寸部件的近净尺寸成型，具有实验设备简单、工艺过程易控制、坯体密度均匀、强度高等突出优点。为了制备出高固相含量、低黏度、高密度的金属陶瓷，分别从注凝成型工艺过程、注凝成型体系和烧结致密化方法等方面进行了研究。研究表明：注凝成型工艺过程主要分为球磨、凝胶、干燥、排胶和烧结；注凝成型体系分为水系凝胶和非水系凝胶；浆料的黏度对坯体的力学性能影响较大；干燥不当会导致坯体的开裂；烧结温度和烧结助剂对烧结体性能有较大的影响。     

甲酸处理的纳米铜无压烧结性能及高温老化研究

介绍了一种基于甲酸铜高温分解反应的纳米铜无压烧结工艺，旨在解决现有铜烧结技术中铜易氧化且需要辅助压力的问题。通过甲酸溶液对纳米铜颗粒（Cu NPs）进行预处理，生成致密的甲酸铜膜，经烧结后最终形成Cu-Cu接头。接头烧结质量试验表明，甲酸反应时间10 min、聚乙二醇（PEG）溶剂、0.048 mm砂纸打磨基材表面以及5℃/min的升温速率为最优烧结条件。在该条件下，实现了纳米铜无压烧结，制备的接头剪切强度可达16.18 MPa，电阻率低至570μΩ/m。经过200 h高温老化实验，接头的剪切强度仍可达到9.38 MPa，验证了该烧结工艺的可靠性。文中所提出的工艺为实现第三代半导体芯片的可靠互联提供了新思路。     

Effect of spark plasma sintering and reinforcements on the formation of ultra-fine and nanograins in AA2024-TiB2-Y hybrid composites

This study reports the influence of sintering mechanism and reinforcement materials on the formation of ultra-fine and nanograins in Al-TiB₂-Y nanohybrid composites. The mechanical properties of the composites and their corresponding micro and nanostructures are correlated. The experimental and characterization results revealed that despite the addition of TiB₂, the hard and brittle Al₃Ti phase formation in the composites was suppressed and hence, their ductility was retained. It was found that yttrium content of 0.3 ?wt% was the optimum amount which created advantageous spark plasma sintering conditions, and the addition of 0.3 ?wt% promoted the formation of bi-modal size grains (ultra-fine and nano) along with micro grains, Ω and other nano precipitates, resulting in a significant enhancement in the composite properties. The formation of ultra-fine and nanograins may be attributed to the combined effect of melting and rapid solidification at necking zones due to Joule's heating and thermo-mechanical fatigue. Among all the sintered composites, the highest hardness (137 HV), ultimate tensile strength (UTS) (496 ?MPa), yield strength (YS) (438 ?MPa) with 15.7% elongation were obtained in the sintered sample reinforced with 1.0 ?wt% TiB₂ and 0.3 ?wt% yttrium.