La2O3对氧化镁陶瓷烧结性能与抗热震性能的影响

本文以纳米氧化镁为主要原料,La2O3为添加剂,聚乙烯醇为结合剂,制备烧结性能良好和抗热震性能优异的氧化镁陶瓷.通过常温力学性能、抗热震性能、XRD和SEM等手段对试样进行分析和表征,重点研究La2O3对氧化镁陶瓷烧结性能及抗热震性能的影响.结果表明:La2O3的加入能够促进氧化镁陶瓷的烧结.从微观结构看出La2 O3加入后可与氧化镁形成固溶体及一些不定形态物质,均匀分布在晶界处,减缓试样在热震时裂纹的尖端应力,阻碍裂纹延伸,有效提高氧化镁陶瓷的抗热震稳定性.经1640℃烧结La2O3的加入量为1;的试样相对密度最高,为99.72;;热震后经1560℃烧结La2O3的加入量为2;的试样常温耐压强度达到最大值,58 MPa.     

Perfluoropolyether–tetrafluoroethylene (PFPE–TFE) block copolymers: An innovative family of fluorinated materials

A new technological platform, based on the chemistry of the peroxidic perfluoropolyethers, has been recently developed for the synthesis of innovative fluorinated materials. Perfluoropolyether–tetrafluorethylene (PFPE–TFE) copolymers are one of the most representative examples of the potential and the flexibility of this technology. By tuning the reaction parameters, the structure of these copolymers can be easily modulated to obtain products with the desired chemical–physical and rheological properties. Applications are endless, from thin film lubrication to gel based greases, to additives for plastics, rubber and other compounds. This technology will lead to entirely new classes of PFPE materials that will fill many of the gaps existing today in markets not currently served by PFPEs.