粉末冶金材料科学与工程
粉末冶金材料科學與工程
분말야금재료과학여공정
POWDER METALLURGY MATERIALS SCIENCE AND ENGINEERING
2015年
3期
338-343
,共6页
热力学%煅烧温度%吉布斯自由能%β″- Al2O3
熱力學%煅燒溫度%吉佈斯自由能%β″- Al2O3
열역학%단소온도%길포사자유능%β″- Al2O3
thermodynamics%calcining temperature%Gibbs free energy%β″-alumina
以Na2CO3和α-Al2O3为原料,Na2CO3与α-Al2O3的物质的量比为1:6,采用固相合成法制备β″/β-Al2O3粉末。通过热力学计算原料粉末在不同温度下可能发生的化学反应的吉布斯自由能,并结合Na2CO3/α-Al2O3混合粉末的 DTA 曲线,研究可能发生的化学反应的温度条件。同时,用 X 射线衍射仪(XRD)对固相合成粉末的物相组成进行分析。结果表明,Na2CO3/α-Al2O3混合粉末在1150℃左右开始发生反应生成β″/β-Al2O3;最适宜的反应温度为1250℃,α-Al2O3全部转化为β/β″-Al2O3,并且β″-Al2O3含量最高;当温度升高到1400℃时,β/β″-Al2O3发生分解,生成α-Al2O3和Na2O,并且随温度升高,更多的β/β″-Al2O3发生分解,而Na2O在高温下挥发会促进β/β″-Al2O3的分解。当煅烧温度超过1500℃时,β″-Al2O3分解还生成微量的NaAlO2。
以Na2CO3和α-Al2O3為原料,Na2CO3與α-Al2O3的物質的量比為1:6,採用固相閤成法製備β″/β-Al2O3粉末。通過熱力學計算原料粉末在不同溫度下可能髮生的化學反應的吉佈斯自由能,併結閤Na2CO3/α-Al2O3混閤粉末的 DTA 麯線,研究可能髮生的化學反應的溫度條件。同時,用 X 射線衍射儀(XRD)對固相閤成粉末的物相組成進行分析。結果錶明,Na2CO3/α-Al2O3混閤粉末在1150℃左右開始髮生反應生成β″/β-Al2O3;最適宜的反應溫度為1250℃,α-Al2O3全部轉化為β/β″-Al2O3,併且β″-Al2O3含量最高;噹溫度升高到1400℃時,β/β″-Al2O3髮生分解,生成α-Al2O3和Na2O,併且隨溫度升高,更多的β/β″-Al2O3髮生分解,而Na2O在高溫下揮髮會促進β/β″-Al2O3的分解。噹煅燒溫度超過1500℃時,β″-Al2O3分解還生成微量的NaAlO2。
이Na2CO3화α-Al2O3위원료,Na2CO3여α-Al2O3적물질적량비위1:6,채용고상합성법제비β″/β-Al2O3분말。통과열역학계산원료분말재불동온도하가능발생적화학반응적길포사자유능,병결합Na2CO3/α-Al2O3혼합분말적 DTA 곡선,연구가능발생적화학반응적온도조건。동시,용 X 사선연사의(XRD)대고상합성분말적물상조성진행분석。결과표명,Na2CO3/α-Al2O3혼합분말재1150℃좌우개시발생반응생성β″/β-Al2O3;최괄의적반응온도위1250℃,α-Al2O3전부전화위β/β″-Al2O3,병차β″-Al2O3함량최고;당온도승고도1400℃시,β/β″-Al2O3발생분해,생성α-Al2O3화Na2O,병차수온도승고,경다적β/β″-Al2O3발생분해,이Na2O재고온하휘발회촉진β/β″-Al2O3적분해。당단소온도초과1500℃시,β″-Al2O3분해환생성미량적NaAlO2。
β″/β-Al2O3 powder was prepared by solid state method using Na2CO3 andα-Al2O3 as raw materials with a molar ratio of 1:6. The reaction temperature of different chemical reactions which might occur during calcination process was investigated by the calculation of Gibbs free energy and differential thermal analysis (DTA) curve of Na2CO3 andα-Al2O3 mixed powder. The phase composition of calcined powder was characterized by X-ray diffraction (XRD). Results show that in the mixed powder, Na2CO3 begins to react withα-Al2O3 to formβ″/β-Al2O3 at the temperature of 1 150℃. The optimum calcination temperature is 1 250℃, at which temperature allα-Al2O3 can transform intoβ″/β-Al2O3 and the content ofβ″- Al2O3 is the most. Theβ″/β-Al2O3 will decompose intoα-Al2O3 and Na2O, when calcining temperature increases to 1 400℃. The decomposition content ofβ″/β-Al2O3 increases with the increasing temperature and the evaporation of Na2O under high temperature accelerates the decomposition ofβ″/β-Al2O3. When the calcining temperature increases to 1 500℃, a small amount of NaAlO2 is produced by the decomposing ofβ″-Al2O3.