含碳铝酸钙粉体的燃烧合成及其微观表征

Synthesis of Calcium Aluminate Containing Carbon Powder by Combustion Method and Its Microstructural Characterization

以CaO2、Al、Al2O3、有机酸钙（草酸钙、硬脂酸钙、葡萄糖酸钙、柠檬酸钙）为原料,FeC2O4为催化剂,通过燃烧合成法制备含碳铝酸钙粉体,采用X射线衍射仪、Raman光谱仪、碳硫仪、扫描电子显微镜、能谱仪和高分辨透射电子显微镜对粉体进行了表征,研究了有机酸钙和FeC2O4掺量对粉体物相组成、碳含量、碳有序度的影响。结果表明：燃烧产物主要物相组成为CaO·Al2O3（CA）和CaO·2Al2O3（CA2）,其中,葡萄糖酸钙原料体系、柠檬酸钙原料体系随有机酸钙掺量的增加,产物中出现了12CaO·7Al2O3（C（12）A7）相,CA2相减少。制备的铝酸钙粉体中存在自由碳,柠檬酸钙原料体系碳含量随柠檬酸钙掺量增加由0.32%（质量分数）增加到0.40%,葡萄糖酸钙原料体系随葡萄糖酸钙掺量增加碳含量先增加后降低,其中碳含量最高为0.80%。圆圈状晶格条纹的碳存在于块状结构的铝酸钙晶粒边沿或被铝酸钙晶粒包裹,其晶面间距为0.33 nm,与碳的（002）晶面一致。铝酸钙晶体具有横向晶格条纹,晶面间距约为0.73 nm,与CA的（002）晶面一致。在葡萄糖酸钙掺量3%（摩尔分数）的配比基础上加入不同量的FeC2O4,随其掺量的增加,碳的有序度呈现先增加后降低的趋势,FeC2O4掺量为0.75%时碳有序度最高。

Calcium aluminate powder containing carbon was prepared with CaO2, Al, Al2O3 and organic acid calcium（calcium oxalate（CaC2O4）, calcium stearate（CaC（36）H（70）O4）, calcium gluconate（CaC（12）H（22）O（14））, calcium citrate（Ca3C（12）H（10）O（14）） as starting materials by a combustion synthesis method. The resultant powder was characterized by X-ray diffraction, Raman spectroscopy, carbon sulfur measurement, scanning electron microscopy and energy dispersive spectroscopy, and high–resolution transmission electron microscopy, respectively. The effects of organic acid calcium and ferrous oxalate with different addition amounts on the phase composition, the content and order of carbon were investigated. The XRD patterns confirm that the main phase compositions of produced power are CaO·Al2O3 and CaO·2 Al2O3, while 12 CaO·7 Al2O3 is an intermediate phase when organic acid calcium in calcium gluconate and calcium citrate system increases. Free carbon exists in the powder, which increases from 0.32%（mass fraction） to 0.40% with the increase of calcium citrate content, however, it firstly increases and then decreases in calcium gluconate system, and the maximum carbon content is 0.80%. The carbon with the circular lattice stripe exists in calcium aluminate powder. Acorrding to the selected area of the diffraction patterns, the lattice planes, including（002）, can be calculated to be the lattice spacing of 0.33 nm of carbon. Calcium aluminate crystal with the transverse lattices fringes, and the spacing of the crystal faces is 0.73 nm, which can be assigned to the（002） lattice planes of CaO·Al2O3 crystal. The order of carbon firstly increases and then decreases with the increase of amount of ferrous oxalate into the starting materials containing calcium gluconate of 3%（mole fraction）, and becomes the maximum when FeC2O4 content is 0.75%.