β-Si3N4在含碳材料中转化为SiC的研究

以β-Si3N4及活性炭黑为原料,按照两者质量比为31制成试样.在埋炭条件下,将试样分别在1480℃、1500℃、1550℃和1600℃保温3 h热处理.利用SEM、EDS及XRD等检测方法,结合热力学分析,研究了高温状态下β-Si3N4在含碳耐火材料中的稳定性以及作为过渡相向碳化硅的转化.结果表明在该试验条件下,β-Si3N4在含碳材料中将作为过渡相向SiC转化,明显的转化温度＞1500℃,1600℃仍存在较多未转化的氮化硅;氮化硅颗粒与炭黑的反应主要从接触面开始,然后向内逐步推进;β-Si3N4的粒度对其转化率影响较大.     

（Nb，Ti）C－Ni金属陶瓷中包裹结构的形成机理及其化学键研究

利用ＳＥＭ，ＥＰＭＡ，ＴＥＭ／ＥＤＡＸ等测试手段对（Ｎｂ，Ｔｉ）Ｃ－Ｎｉ金属陶瓷中的包裹结构形成机理作了研究。结果表明：它是由于该金属陶瓷在烧结时，细小的（Ｎ５，Ｔｉ）Ｃ粒溶解在熔融态的Ｎｉ中，当Ｔｉ，Ｎｂ及Ｃ的浓度达到大颗粒的饱和浓度时，在大颗粒表面沉淀，继而Ｎｉ向其扩散而形成的。用离散变分──Ｘ＿α方法计算表明：包裹层的金属键程度要比包裹结构中心的高。     

陶瓷抛光砖粉作混合材对水泥性能的影响

研究了陶瓷抛光砖粉作水泥混合材对水泥相关性能的影响。研究结果表明：抛光砖粉作水泥混合材时，水泥的标准稠度用水量增加，初凝时间缩短、终凝时间略有延长；水泥28d胶砂强度活性指数可达82％；抛光砖粉掺量在30％以下，随其掺量增加，Marsh时间明显延长，水泥浆体的流动性变差；抛光砖粉的掺入基本不影响水泥与聚羧酸类减水剂MB—SR3的饱和点，但影响水泥与萘系减水剂FDN的相容性。     

凝胶注模成型制备刚玉-尖晶石耐火材料

以板状刚玉颗粒和富铝尖晶石细粉为主要原料 ,以含丙烯酰胺 (AM)、N ,N’ -亚甲基双丙烯酰胺 (MBAM)和分散剂AN - 2 0 0 0的水溶液为预混液 ,制备出临界粒度为 3mm ,固相体积分数为 80 %的刚玉 -尖晶石混合浆料 ,加入引发剂过硫酸铵(APS)和催化剂N ,N ,N’ ,N’ -四甲基乙二胺(TEMED)快速搅拌混合 15s后注入钢模中 ,于 4 0℃引发凝胶反应 ,脱模后于湿度不低于 5 0 %的环境中干燥 4 8h ,再于 110℃干燥 2 4h ,然后在空气中于5 30℃以上排胶 ,再经 16 0 0℃保温 2h烧成。结果表明 :坯体的干燥强度达 11.6MPa ;烧成后试样的体积密度为 3.0 6g·cm-3 ,显气孔率为 16 .5 % ,耐压强度为 72 .5MPa ;烧成后试样基质中除了极少量的刚玉相外 ,其余的全为尖晶石相 ,在制备过程中没有被污染。     

智能高分子材料

介绍了几种新型的智能高分子材料,指出合成新的聚合物、制造构造规则的高分子凝胶及增加材料的表面积与体积比是加快智能高分子材料响应速率的方法,同时指出仿生化和模糊化是智能高分子材料的发展方向。     

Theoretical progress in non-equilibrium grain-boundary segregation (Ⅰ): Thermally induced non-equilibrium grain-boundary segregation and intergranular embrittlement

The research progress of non-equilibrium grain-boundary segregation theories in the last 20 years is reviewed. Based on studies by the present authors, the critical time of non-equilibrium segregation and its impact on the development of non-equilibrium segregation theories are described. Quasi- thermo- dynamics and kinetics for thermal non-equilibrium grain boundary segregation are detailed along with a non-equilibrium grain boundary cosegregation model. The experimental validation of the theories and thei...     

纳米Fe_2O_3包覆云母珠光颜料的合成及表面形貌

采用液相沉积法合成了纳米Fe2O3包覆云母珠光颜料。利用综合热分析仪（DSC-TGA）、场发射扫描电镜（FE-SEM）对样品的热处理工艺和表面形貌进行表征,利用树脂涂卡对珠光颜料的珠光性能进行表征。结果表明,水解包膜温度75℃、pH 3.3、FeCl3溶液浓度为1 mol/L,以10℃/min升至800℃进行30 min煅烧,制得的珠光颜料的表面纳米包覆膜平整致密,具有明亮鲜艳的金黄色珍珠光泽。     

Mechanism of protective film formation during CO2 corrosion of X65 pipeline steel

Electrochemical techniques, X-ray diffraction (XRD), and scanning electron microscopy (SEM) were applied to study the corrosion behaviors of X65 steel in static solution with carbon dioxide (CO2) at 65°C. The results show that iron carbonate (FeCO3) deposits on the steel surface as a corrosion product scale. This iron carbonate scale acts as a barrier to CO2 corrosion, and can reduce the general corrosion rate. The protection ability of the scale is closely related to the scale morphological characteristics...     

One-step preparation of carbon nanotubes with nickel as the core

CNTs with core-shell structure were successfully synthesized by a microwave-assisted polyol method,and magnetic Ni nanoparticles were employed as a catalyst. The preparation method is fast and simple. The structures,morphology and magnetic properties of the as-synthesized samples were investigated using Raman spectrometer,X-ray diffraction (XRD),transmission electron microscopy (TEM),vibrating sample magnetometer (VSM),respectively. The XRD results suggested that Ni particles used as a catalyst in our exper...     

Al2O3-SiO2质材料抗Al2O3附着的研究

通过实验和热力学分析确认了Al2O3-SiO2质浸入式水口内衬材料的组成对Al2O3附着量的影响.在Al2O3-SiO2质材料中,以Al2 O3-3Al2O3@2SiO2的抗Al2O3附着效果最好,故认为使用不合C的Al2O3-3Al2O3@2SiO2材料制作防止Al2O3堵塞的浸入式水口内衬是可行的.