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| 添加ZrO2对镁钙砂抗水化性能的影响 |
| Effect of ZrO2 addition on the hydration resistance of MgO-CaO clinkers |
| 投稿时间：2018-09-27 |
| DOI： |
| 中文关键词: 镁钙砂 ZrO2 CaO 烧结性能 抗水化性 |
| 英文关键词: MgO-CaO clinkers ZrO2 CaO sintering property hydration resistance |
| 基金项目:国家自然科学基金面上项目(51772222). |
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| 中文摘要: |
| 以w(CaO)为55%的镁钙砂细粉为原料、ZrO2为添加剂,在1550 ℃温度下烧结5 h制备镁钙试样,研究了添加ZrO2对镁钙试样物相组成、显微结构、烧结性能和抗水化性能的影响。结果表明,添加ZrO2能促进镁钙材料的烧结,且随着ZrO2加入量的增加,试样的体积密度逐渐增大,显气孔率减小,抗水化性能逐渐增强,这是由于ZrO2的加入增大了Ca2+的空位浓度,有利于Ca2+的扩散,促进了镁钙试样的烧结致密化和试样中CaO晶粒的长大。此外,ZrO2还可与游离态CaO反应生成不易水化的CaZrO3,该反应发生在晶界等容易水化的部位,改变了镁钙试样的显微结构,又进一步提高了材料抗水化性能；当ZrO2添加量超过5%后,试样的各项性能变化趋于平缓。综合考虑,该镁钙试样中ZrO2的适宜添加量为5%。 |
| 英文摘要: |
| With MgO-CaO clinkers containing 55%CaO as raw material and ZrO2 as additive, the magnesium-calcium materials were prepared by sintering at 1550 ℃ for 5 h. The effects of ZrO2 addition on the phase composition, microstructure, sintering property and hydration resistance of the as-prepared MgO-CaO materials were studied. The results reveal that the addtion of ZrO2 is beneficial to promote the sintering of MgO-CaO materials. Moreover, with the increase of ZrO2 content, the bulk density of the sample increases, the apparent porosity decreases, and the hydration resistance of the material is therefore improved. This is because the addition of ZrO2 increases the vacancy concentration of Ca2+ and therefore accelerates the diffusion of calcum ions, which will promote the sintering densification as well as the growth of CaO grains in MgO-CaO samples. In addition, the hydration-resistant CaZrO3 can be generated from the reaction between ZrO2 and free CaO. This reaction mainly takes place at the grain boundaries, which leads to the microstructural change of MgO-CaO materials and further enhances its hydration resistance. When the ZrO2 content is more than 5%, the property changes of the as-prepared MgO-CaO samples tend to be steady. Taking all those factors into consideration, a suitable addition amount of ZrO2 in this magnesium-calcium material is 5%. |
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