Phase Evolution of Si_3N_4 Ceramic with Additives from Li_2O-Y_2O

Phase Evolution of Si_3N_4 Ceramic with Additives from Li_2O-Y_2O_3

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外文摘要：This paper deals with the α- to β- Si_3N_4 phase transformation during pressureless sintering of Si_3N_4 with LiYO_2 as a sintering additive。 The phase evolution after heat treatments in the temperature range from 1200 to1500℃ shows that α-Si_2N_4 and β-Si_3N_4 are the main crystalline phases in all stages of annealing。 At 1200℃， the initial LiYO_2 sintering additive completely disappears。 X-ray patterns show a remarkable broadening of diffraction lines in the regions around 27-29° and 32-34° 2θ， which can be ascribed to the Y_5(SiO_4)_3N ("N-apatite") phase。 This indicates that the nucleation and formation of crystalline N-apatite takes place at this temperature， which is the onset of liquid formation。 At 1600℃， a complete conversion of the secondary phase into the liquid one and of α- to β-Si_3N_4 takes place。

外文关键词：

secondary phaseSi_3N_4X-Ray diffraction

作者：

B. Matovic、S. Boskovic

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作者单位：

Vinca Institute of Nuclear Sciences, Lab. 170, Belgrade, Serbia and Montenegro

会议名称：

Progress in Advanced Materials and Processes

会议地点：

Herceg-Novi(YU);Herceg-Novi(YU)

会议母体文献：

Yugoslav Materials Research Society Conference on Progress in Advanced Materials and Processes; 20030915-20030919; Herceg,Novi; YU

页码：

P.447-451

出版时间：

2003