【摘要】： 本研究以化學(xué)純Li_2CO_3、Al_2O_3、SiO_2為主要原料,添加TiO_2、ZrO_2、P_2O_5晶核劑,采用燒結(jié)法制備了LAS系微晶玻璃。借助正交試驗(yàn)并采用DTA、XRD、TEM、SEM等分析測(cè)試方法,研究玻璃組成、熱處理制度、顯微結(jié)構(gòu)和性能四者之間的相互聯(lián)系和影響。確定了合理的微晶玻璃組成和熱處理制度,制備出具有較高力學(xué)性能和合理晶相組成的低膨脹微晶玻璃。在此基礎(chǔ)上,進(jìn)一步研究了TiO_2、ZrO_2、P_2O_5晶核劑對(duì)微晶玻璃結(jié)構(gòu)及性能的影響。 結(jié)果表明:當(dāng)SiO_2/ Al_2O_3摩爾比為5∶1時(shí),微晶玻璃中只存在顆粒狀的晶體,隨SiO_2/Al_2O_3的減小,有纖維狀的晶體析出。在燒結(jié)溫度較高,晶化較充分的情況下,微晶玻璃的熱膨脹系數(shù)隨著SiO_2/Al_2O_3的減小而增大,其抗折強(qiáng)度則先增加后減小。初步探討了燒成溫度對(duì)性能的影響,當(dāng)燒成溫度為1000℃時(shí),微晶玻璃的主晶相為β-石英固溶體,此時(shí)微晶玻璃熱膨脹系數(shù)低,但制品致密度低,力學(xué)性能差;隨著燒成溫度升高,β-石英固溶體開始向β-鋰輝石固溶體轉(zhuǎn)變,膨脹系數(shù)有所增大。當(dāng)燒成溫度提高到1200℃時(shí),強(qiáng)度大于70MPa。 研究LAS微晶玻璃熱處理制度對(duì)熱膨脹系數(shù)及力學(xué)性能的影響,確定較佳的熱處理制度為:核化溫度780℃、核化時(shí)間1h,晶化溫度860℃、晶化時(shí)間1.5h,升溫至1200℃燒結(jié)。此時(shí)微晶玻璃的熱膨脹系數(shù)為0.67×10-6/℃,強(qiáng)度達(dá)到80.48MPa。LAS系統(tǒng)微晶玻璃的析晶過程是一個(gè)分相促進(jìn)析晶的過程,并且整個(gè)過程受成核-長(zhǎng)大機(jī)理控制。當(dāng)核化溫度為760℃時(shí),晶核數(shù)量少,而當(dāng)核化溫度為820℃時(shí),晶核長(zhǎng)大粗化,只有在780℃下進(jìn)行核化處理時(shí),晶核數(shù)量多而粒徑小。 燒結(jié)法制備LAS系微晶玻璃時(shí),晶核劑種類及含量只會(huì)影響晶體的形貌,并不會(huì)改變其主晶相,即使不添加任何晶核劑,依然能獲得具有一定結(jié)晶度的制品。P_2O_5有利于析出纖維狀的β-鋰輝石固溶體,而TiO_2、ZrO_2則有利于析出顆粒狀的β-鋰輝石固溶體,且隨著TiO_2、ZrO_2總量的增大,晶體顆粒減小。當(dāng)TiO_2、ZrO_2及P_2O_5的比為1∶1∶3時(shí),微晶玻璃的熱膨脹系數(shù)為0.61×10-6/℃,強(qiáng)度達(dá)到85.71MPa。
[Abstract]:In this study, the LAS system glass-ceramics were prepared by sintering method with the chemical pure Li2COS _ 3Al2O-Al _ 2O _ 2 as the main raw material and adding TiO2ZR _ 2O _ 2P _ 2O _ 5 as the nucleating agent. The relationship and influence of glass composition, heat treatment system, microstructure and properties of glass were studied by means of orthogonal test and SEM. The reasonable composition and heat treatment system of glass-ceramics were determined and a low expansion glass-ceramics with high mechanical properties and reasonable crystalline phase composition was prepared. On this basis, the effect of tio _ 2o _ 2o _ 2O _ 5 nucleating agent on the structure and properties of glass ceramics was further studied. The results show that when the molar ratio of SiO_2/ Al_2O_3 is 5:1, there are only granular crystals in the glass-ceramics, and with the decrease of SiO_2/Al_2O_3, there are fibrous crystals precipitated. When the sintering temperature is high and the crystallization is sufficient, the thermal expansion coefficient of glass-ceramics increases with the decrease of SiO_2/Al_2O_3, and the flexural strength of glass-ceramics increases first and then decreases. The effect of sintering temperature on the properties was discussed. When the sintering temperature was 1000 鈩，

本文編號(hào)：2197372