氮化硼陶瓷晶粒尺寸和晶型对力学及抗溅射性能的影响

发布时间：2018-06-18 04:12

本文选题：h-BN + c-BN　；参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：本文将行星球磨后h-BN粉体进行热压烧结,通过调节保温时间和热压烧结的温度,制得了不同晶粒尺寸的h-BN陶瓷。用h-BN和c-BN粉体分别和熔石英进行热压烧结,制备了h-BN/Si O2和c-BN/Si O2复合材料。利用XRD、SEM等分析手段表征了材料的物相以及微观形貌;利用万能试验机研究h-BN陶瓷的力学性能;通过离子溅射实验,研究了h-BN陶瓷抗离子溅射性能,分析了溅射后材料表面的物相、粗糙度、微观形貌的特征,并对材料的溅射机理进行了探索。研究表明,在保温相同时间的条件下,随着热压烧结温度的提高,h-BN陶瓷的晶粒尺寸逐渐变大,从在1600oC保温0.5h时的0.5μm增长到在1900oC保温0.5h时的4μm。在烧结温度相同的条件下,随着保温时间的增加,h-BN陶瓷的晶粒尺寸也逐渐增加,从在1800oC保温1h的4μm增长到在1800oC保温5h时的8μm。随着h-BN陶瓷材料晶粒尺寸的增加,其抗弯强度有明显的降低,其关系符合Hall-Petch公式。晶粒尺寸为0.5μm时h-BN陶瓷的弹性模量、抗弯强度和断裂韧性最高,分别为50.1GPa、163.5MPa、和2.85 MPa?m1/2。在不同离子能量相同溅射时间和相同离子能量不同溅射时间的溅射条件下,h-BN陶瓷材料的抗离子溅射特性都随着晶粒尺寸的增加而逐渐变差,表面粗糙度和溅射侵蚀速率随晶粒尺寸的增加而逐渐增加。h-BN陶瓷的溅射侵蚀速率随溅射时间增加而降低,但是随着溅射能量的增加而增加。分别采用h-BN和c-BN粉体和熔石英为原料,热压烧结制备了不同晶型的BN/Si O2复合材料;随溅射离子能量增加,溅射侵蚀速率逐渐增加;在相同离子能量条件下,随溅射时间增加溅射侵蚀速率逐渐降低;h-BN/Si O2复合材料中h-BN晶粒比熔石英和方石英更容易被溅射掉,而c-BN/Si O2复合材料受溅射时,首先是包覆c-BN晶粒的熔石英被溅射掉,然后c-BN晶粒再由于脱粘而与熔石英基体发生分离,造成整体材料的溅射损失。
[Abstract]:In this paper, h-BN powders were hot-pressed and sintered after planetary ball milling. By adjusting the holding time and the sintering temperature, the h-BN ceramics with different grain sizes were prepared. The h-BN / SiO2 and c-BN / SiO2 composites were prepared by hot pressing sintering of h-BN and c-BN powders with fused quartz, respectively. The phase and microstructure of h-BN ceramics were characterized by XRDX SEM, the mechanical properties of h-BN ceramics were studied by universal testing machine, and the anti-ion sputtering properties of h-BN ceramics were studied by ion sputtering experiments. The surface phase, roughness and microstructure of the sputtering materials were analyzed, and the sputtering mechanism of the materials was explored. The results show that the grain size of h-BN ceramics increases gradually with the increase of sintering temperature, from 0.5 渭 m at 1600oC holding time to 4 渭 m at 1900oC holding 0.5h. At the same sintering temperature, the grain size of h-BN ceramics increased gradually with the increase of holding time, from 4 渭 m at 1800oC for 1h to 8 渭 m at 1800oC for 5h. With the increase of the grain size of h-BN ceramics, the bending strength of h-BN ceramics decreases obviously, and the relationship between them accords with the Hall-Petch formula. When the grain size is 0.5 渭 m, the elastic modulus, flexural strength and fracture toughness of h-BN ceramics are the highest, which are 50.1 GPA 163.5 MPa and 2.85 MPa / m 1 / 2, respectively. The sputtering resistance of h-BN ceramics becomes worse with the increase of grain size under the same sputtering time with different ion energy and different sputtering time with the same ion energy. The surface roughness and sputtering erosion rate increased with the increase of grain size. The sputtering erosion rate of H-BN ceramics decreased with the increase of sputtering time, but increased with the increase of sputtering energy. Using h-BN and c-BN powders and fused quartz as raw materials, different crystalline BN / Sio _ 2 composites were prepared by hot pressing sintering. The sputtering erosion rate increased gradually with the increase of sputtering ion energy, and at the same ion energy, With the increase of sputtering time, the erosion rate of h-BN / Sio _ 2 composites decreases gradually, and the h-BN grains are easier to be sputtered than fused quartz and cristobalite, while when c-BN / Sio _ 2 composites are sputtered, the fused quartz coated with c-BN grains is first sputtered off. Then the c-BN grain is separated from the fused quartz matrix due to debonding, resulting in the sputtering loss of the whole material.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ174.1

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