(中南大學(xué) 粉末冶金國家重點實驗室，長沙 410083)
摘 要: 采用反應(yīng)燒結(jié)工藝制備鈮鎂酸鉛陶瓷，研究不同Mg源反應(yīng)物對陶瓷物相組成和微觀結(jié)構(gòu)的影響。結(jié)果表明，以MgO為反應(yīng)物時，在升溫過程中部分PbO未參與反應(yīng)，即使在1 200 ℃保溫4 h后仍會有Pb1.83Nb1.71Mg0.29O6.39焦綠石相殘留，對晶粒生長及致密化進(jìn)程起阻礙作用，難以在低溫下實現(xiàn)高相對密度，基體晶粒在PbO熔化后通過溶解−析出機制形成近球狀形貌。以(MgCO3)4·Mg(OH)2·5H2O為反應(yīng)原料時，由其熱分解所得的MgO具有更為細(xì)小的粒度和較高的反應(yīng)活性，在850 ℃保溫1 h即可充分反應(yīng)獲得單一鈣鈦礦物相，保溫4 h后相對密度可達(dá)95%，晶粒形貌隨溫度升高從近球狀演變成緊密排列的多面體。
關(guān)鍵字: 鈮鎂酸鉛；壓電陶瓷；反應(yīng)燒結(jié)；鎂源反應(yīng)物
（State Key laboratory for Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:Abstract: Pb(Mg1/3Nb2/3)O3 ceramics were prepared by reaction-sintering process. The effect of magnesium precursors on the phase composition and microstructure of ceramics was investigated. The results show that some PbO does not participate in the synthesis reaction when using MgO as a reactant during heating-up process, leading to the residue of Pb1.83Nb1.71Mg0.29O6.39 pyrochlore phase even sintered at 1 200 ℃ for 4 h. The pyrochlore phase retards the grain growth and densification. The high relative density can’t be achieved at low temperature. After melting of PbO, the nearly spherical grain morphology is formed through dissolving-precipitating mechanism. When (MgCO3)4·Mg(OH)2·5H2O reactant is used, fine MgO with high reactive activity is obtained from its composition. The completion of reaction to obtain single-phase perovskite is achieved at 850 ℃ for 1 h. The relatively density is 95% sintered at 850 ℃ for 4 h. The polyhedral-shaped grains arranging tightly are formed during heating-up process
Key words: Pb(Mg1/3Nb2/3)O3; piezoelectric ceramics; reaction-sintering process; magnesium precursor
