Synthesis of Cordierite by Decomposition of Metal Nitrates on the Surface of Carbon Black Powder

Cordierite precursor was obtained through a process, which involved the decomposition of metal nitrates on the surface of ultrafine carbon black powder between 100-300℃ and the gasification of the carbon black at higher temperature in air. The average size of the particles, which were heat-treated at 700℃ for 10h, is about 1020nm, and the specific surface area is about 129m 2/g. The experimental results show that the ultrafine particles of cordierite precursor can be produced by this process. The precursor powder was calcined at different temperatures. X-ray diffraction examination indicates that β-quartz is crystallized from the amorphous matrix around 850℃ firstly and then MgO-Al 2O 3 spinel and α-cordierite appears. Above 1000℃, MgO-Al 2O 3 spinel and cristobalite disappear gradually and form an intermediate phase (sapphirine). At around 1300℃, the main phase is α-cordierite, and no other phase is detected.

快速分析白炭黑中SiO_2含量

根据酸碱中和滴定的机理 ,测定白炭黑中SiO2 含量。此方法省电、省时 ,具有较高的准确性。

Preparation and Properties of Si2N2O Ceramics for Microwave Sintering Furnaces

Si2N2O ceramics were prepared using amorphous Si3N4 as the raw material and Li2CO3 as the sintering additive through vacuum multi-stage sintering.The influence of the Li2CO3 addition(0%,1%,2%,3%,and 5%,by mass)on the phase composition,the microstructure,the porosity,the mechanical properties,the dielectric constant and the tangent of the dielectric loss angle of the porous Si2N2O ceramics was investigated.The results reveal that a suitable addition of Li2CO3 can promote the generation of Si2N2O but excessive or inadequate Li2CO3 causes decomposition of Si2N2O ceramics.The prepared porous Si2N2O ceramics have good mechanical properties,good thermal shock resistance,and low dielectric properties,which have excellent potential for application in microwave sintering furnaces.

Luminescence properties of Eu^(2+) doped BaAl_2Si_2O_8 phosphor for white LEDs

The BaAl2Si2O8:Eu2+blue emitting phosphor was obtained through the one-step calcination process of precursors prepared bychemical co-precipitation method. The phase structure and luminescence propertied of the phosphor were investigated usingX-ray diffraction (XRD) and a fluorescence spectrophotometer. The excitation spectrum exhibited a broad band between 230nm and 400 nm and the emission peaking at about 470 nm was observed, which originated from the allowed f-d transition ofEu2+ions at Ba2+sites. Owing to the different optimal concentrations under different excitation wavelengths (254 nm and 365nm), the energy-transfer mechanism in this phosphor has changed from the dipole-dipole interaction to the exchange interac-tion of Eu2+ions.

白炭黑/炭黑配比对天然橡胶基复合材料性能的影响

以硅烷偶联剂作为白炭黑(SiO_2)的表面改性剂,以改性SiO_2/炭黑作为天然橡胶(NR)的混合填料,采用半有效硫化体系制备了NR基复合材料。研究结果表明:当m(SiO_2)∶m(炭黑)=20∶40时,硫化胶中混合填料分散均匀,并且硫化胶的撕裂强度(62 k N/m)相对最高、交联密度相对最大且佩恩效应相对较弱。

载Zn白炭黑抗菌剂的制备及抗菌性能的研究

采用溶胶-凝胶法制取白炭黑载体,在一定条件下将具有杀菌性能的Zn2+附着在白炭黑载体上,制得含Zn2+杀菌活性成份的无机粉体抗菌材料。运用ICP、FTIR和SEM等手段对材料中抗菌离子含量、抗菌离子与载体的结合方式以及抗菌白炭黑的形态结构等进行了表征,并利用菌落计数法对材料的抗菌性能进行研究。结果表明,载锌抗菌白炭黑结构较白炭黑松散,且分散性好;Zn2+是通过离子交换方式结合到白炭黑上的;改性后的载锌抗菌白炭黑的杀菌率达99%以上。

铜型抗菌白炭黑的改性研究

通过添加表面活性剂和有机溶剂对铜型抗菌白炭黑进行改性研究。并运用ICP、粒度分布仪对改性后铜型抗菌白炭黑中抗菌离子含量、粒度进行了表征;利用菌落计数法对改性后材料的抗菌性能进行了研究;并与未改性的铜型抗菌白炭黑进行比较。结果表明,改性后的铜型抗菌白炭黑中,抗菌离子含量高于未改性前;结构较改性前松散,且分散性好;平均粒径为3μm且均一;杀菌率达99%以上。具有较好的热稳定性和光稳定性。

铜型抗菌白炭黑的制备及抗菌性能研究

研究了铜型抗菌白炭黑的制备及抗菌性能。试验采用溶胶-凝胶法制取白炭黑载体,在一定条件下,将具有杀菌性能的Cu2+附着在白炭黑载体上,制得含Cu2+杀菌活性成份的无机粉体抗菌材料。运用ICP、FTIR和粒度分布仪等手段对材料中抗菌离子含量、抗菌离子与载体的结合方式以及抗菌白炭黑的粒度分布等进行了表征。并利用菌落计数法对材料的抗菌性能进行研究。结果表明,载铜抗菌白炭黑的粒度分布较均一;Cu2+是通过离子交换方式结合到白炭黑上的;铜型抗菌白炭黑的杀菌率达98%以上。