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Development and High Resistance in Severe Environment of β-Sialon Composites Materials with Controlled Microstructure

可控微观结构β-Sialon复合材料的研制及其耐恶劣环境性能

基本信息

批准号：
09355029
负责人：
SHIMADA Shiro
金额：
$ 15.68万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

(1)F-doped sialons (β-, o-, and α/β-types) of a single phase were successfully synthesized using AIFィイD23ィエD2 or topaz as a reagent of fluorine at 1500-1780℃ by HIPing method. Fluorine was found to exist in grassy phase of all the sintered pellets of the sailons by TEM-EDX. The F-doped β-sialon showed much better corrosion resistance in NaCl vapors at 1300℃ than the pure β-silaon.(2) The wet oxidation of the α-SiィイD23ィエD2NィイD24ィエD2 and theβ-sialon (SiィイD26-zィエD2AlィイD2zィエD2OィイD2zィエD2NィイD28-zィエD2, z = 1, 2 and 3) powders at temperatures of 1000℃ to 13000℃ in 0〜20 kPa water vapor was followed by XRD, ィイD129ィエD1Si and ィイD117ィエD1O MAS NMR, transmission electron microscope (TEM), and thermogravimetric analysis. A considerable difference was not found in the oxide products and microstructure of the samples obtained by the wet and dry oxidation; the oxide phase was composed of very fine acicular mullite grains and amorphous SiOィイD22ィエD2. The oxidation was described by the linear kinetics in two successive early stages at reacted fractions of 0-20%, followed by the parabolic kinetics represented by the Ginstling-Brounshtein equation at fractions of 20〜80%. The wet oxidation rates in the diffusion process were 1.5〜10 times greater than in the dry oxidation, with the activation energies of 440, 350, 330 and 240 kJ molィイD1-1ィエD1 for the α-SiィイD23ィエD2NィイD24ィエD2, and the z = 1, 2 and 3 sialons, respectively. The dependency of the rate on water vapor pressure (0〜20 kPa) in the diffusion process was parabolic, indicative of the diffusion of OHィイD1-ィエD1. ィイD117ィエD1O atoms from HィイD22ィエD2ィイD117ィエD1O water vapor were detected in the oxide product, SiOィイD22ィエD2 and mullite by ィイD117ィエD1O MAS NMR when the sialon was oxidized in Ar/HィイD22ィエD2ィイD117ィエD1O and Ar/OィイD22ィエD2/HィイD22ィエD2ィイD117ィエD1O, indicating that oxygen atoms from water vapor make an nearly equal amount of mullite and SiOィイD22ィエD2.

（1）采用热等静压法，以AIF Sialon D23 Sialon D2或黄玉为氟试剂，在1500-1780℃合成了单相的掺氟Sialon（β型、O型和α/β型）。TEM-EDX分析表明，氟均存在于烧结球团的草相中。在1300℃的NaCl蒸汽中，掺F β-sialon的耐蚀性明显优于纯β-sialon。(2)研究了α-Si_（23）Si_（24）在0 ~ 20 kPa水蒸气中，在1000℃ ~ 13000℃的温度下，对（Si）D26-z掺杂D2 Al掺杂D2 z掺杂D2 O掺杂D2 z掺杂D2 N掺杂D28-z掺杂D2，z = 1、2和3）粉末进行XRD、XRD D129掺杂D1 Si和XRD D117掺杂D1 O MAS NMR，透射电子显微镜（TEM）和热重分析。一个相当大的差异是没有发现在氧化产物和显微结构的样品通过湿氧化和干氧化;氧化物相是由非常细的针状莫来石晶粒和无定形的SiO D22 D2。在0- 20%的反应分数下，氧化反应在两个连续的早期阶段由线性动力学描述，然后在20 - 80%的分数下由Ginstling-Brounshtein方程表示的抛物线动力学描述。扩散过程中的湿氧化速率是干氧化的1.5 ~ 10倍，α-Si_（23）Si_（24）Si_（23）Si在扩散过程中，速率对水蒸气压（0 ~ 20 kPa）的依赖性呈抛物线，表明OH的扩散过程是OH的扩散过程。当Sialon在Ar/H_（22）N_（2这表明来自水蒸气的氧原子形成几乎等量的莫来石和SiO_2 O_2D_2D_2。