选用登封轻烧矾土(Al2O3含量为85wt%)、电熔镁铝尖晶石、高纯电熔镁砂、Al粉和少量的活性材料氮化气氛下制备矾土基Mg Al ON复合材料,考察了Mg Al ON含量及烧成温度对制备矾土基Mg Al ON复合材料性能的影响。结果表明:随着Mg Al ON加入...选用登封轻烧矾土(Al2O3含量为85wt%)、电熔镁铝尖晶石、高纯电熔镁砂、Al粉和少量的活性材料氮化气氛下制备矾土基Mg Al ON复合材料,考察了Mg Al ON含量及烧成温度对制备矾土基Mg Al ON复合材料性能的影响。结果表明:随着Mg Al ON加入量的增加,显气孔率、线变化率及增重率逐渐增大,材料体积密度逐渐减少,常温抗折强度呈上升趋势;随着烧成温度的提高,试样的体积密度略有减小,显气孔率增大,常温抗折强度逐渐增大,1500℃下氮化烧成的制品性能最好;矾土基Mg Al ON复合镁铝尖晶石材料比矾土基Mg Al ON复合镁质材料密度大,强度高,氮化效果好。展开更多
BN-MgA1ON composites were prepared by hot-pressing sintering under nitrogen atmosphere with BN-Mg- A1ON composite powders as raw material and Y2 O3 as sintering additive. Based on thermodynamic analysis, the oxi- dati...BN-MgA1ON composites were prepared by hot-pressing sintering under nitrogen atmosphere with BN-Mg- A1ON composite powders as raw material and Y2 O3 as sintering additive. Based on thermodynamic analysis, the oxi- dation resistance of BN-MgAION composites was investigated and the dynamics of oxidation process was also ana- lyzed. The oxidation process and the micro-morphology of the samples before and after oxidation were characterized by X-ray diffraction and scanning electron microscopy. The dynamics of oxidation resistance of the BN-MgA1ON composites was investigated via the analysis of the constant temperature oxidation mass gain curves. The results show that the main components of the material are MgA1ON, Sialon, BN and CaYAI3 07 at 1 650--1750 ＊C, and the content of CaYA1307 decreases as the sintering temperature increases. The BN-MgA1ON composites prepared at 1750 ℃ is uniform and compact with the balanced distributions of A1, Mg, O, and N. The oxidation process of BN- MgA1ON composites in air mainly consists of MgAION, Sialon and BN oxidation. The section after being oxidized at 1000--1300 ℃ involves three layers, namely, the outer layer, the middle layer and the inner layer. The oxidation process follows the parabola model. The apparent activation energy of the oxidation process is 2.13 × 10 5 J/mol and the frequency factor is 4.66 × 10 6.展开更多
文摘选用登封轻烧矾土(Al2O3含量为85wt%)、电熔镁铝尖晶石、高纯电熔镁砂、Al粉和少量的活性材料氮化气氛下制备矾土基Mg Al ON复合材料,考察了Mg Al ON含量及烧成温度对制备矾土基Mg Al ON复合材料性能的影响。结果表明:随着Mg Al ON加入量的增加,显气孔率、线变化率及增重率逐渐增大,材料体积密度逐渐减少,常温抗折强度呈上升趋势;随着烧成温度的提高,试样的体积密度略有减小,显气孔率增大,常温抗折强度逐渐增大,1500℃下氮化烧成的制品性能最好;矾土基Mg Al ON复合镁铝尖晶石材料比矾土基Mg Al ON复合镁质材料密度大,强度高,氮化效果好。
基金Item Sponsored by National Natural Science Foundation of China(50904022)Education Department of Hebei Province Outstanding Youth Fund Project of China(Y2011116)
文摘BN-MgA1ON composites were prepared by hot-pressing sintering under nitrogen atmosphere with BN-Mg- A1ON composite powders as raw material and Y2 O3 as sintering additive. Based on thermodynamic analysis, the oxi- dation resistance of BN-MgAION composites was investigated and the dynamics of oxidation process was also ana- lyzed. The oxidation process and the micro-morphology of the samples before and after oxidation were characterized by X-ray diffraction and scanning electron microscopy. The dynamics of oxidation resistance of the BN-MgA1ON composites was investigated via the analysis of the constant temperature oxidation mass gain curves. The results show that the main components of the material are MgA1ON, Sialon, BN and CaYAI3 07 at 1 650--1750 ＊C, and the content of CaYA1307 decreases as the sintering temperature increases. The BN-MgA1ON composites prepared at 1750 ℃ is uniform and compact with the balanced distributions of A1, Mg, O, and N. The oxidation process of BN- MgA1ON composites in air mainly consists of MgAION, Sialon and BN oxidation. The section after being oxidized at 1000--1300 ℃ involves three layers, namely, the outer layer, the middle layer and the inner layer. The oxidation process follows the parabola model. The apparent activation energy of the oxidation process is 2.13 × 10 5 J/mol and the frequency factor is 4.66 × 10 6.
