【作者】 王征；

【导师】 贾德昌；

【作者基本信息】 哈尔滨工业大学 ， 材料学， 2015， 硕士

【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。更多还原

【Abstract】 h-BN powders was ball milled to be sub-microned, and the hot-pressing sintering time and temperature was controlled to get different grain sizes of ceramic.h-BN and c-BN powders and fused quartz were hot-pressing sintered, to prepare the h-BN/Si O2 and c-BN/Si O2 composite materials.Using the XRD, SEM to characterize the phase and microstructure of materials; universal testing machine was used to study h-BN ceramic mechanical properties;byionerosion experiments, studied the h-BN ceramic ion sputtering resistance, analysed the after erosion phase on the surface of the material, roughness and microstructure characteristics, and has carried on the exploration to the sputtering mechanism of the material.Studies have shown that under the condition of the same time, with the improvement of hot pressing sintering temperature, h-BN ceramic grain size increases gradually, when theholding time is 0.5h, temperature increase from 1600 oC to 1900 oC, the grain size increase from 0.5μm to 8μm. h-BN ceramic grain size also increase with the holding time, when the temperature is 1800 oC, the holding time increased from 1h to 5h, the grain size increase from 4μm to 8μm.With the increase of h-BN ceramic grain size, the bending strength decrease, and the relationship between bending strength and grain size conform to the Hall-petch formula.The h-BN ceramic with the grain size of 0.5μm has the best elastic modulus, bending strength and fracture toughness, as 50.1 GPa, 163.5 MPa and 2.85 MPa×m1/2.Theion sputtering resistance properties of h-BN ceramic material gradually decreased with the increase of grain size, surface roughness and the sputtering rate gradually increased with the increase of the grain size.The erosion rate increase with the ion energy, while decrease with the erosion time.h-BN and c-BN were used respectively and fused quartz as raw materials, were hot pressied to different crystal forms of BN/Si O2 composite materials. With the increase of sputtering ion energy, sputtering rate increase gradually. Under the condition of the same ion energy, when the sputtering time increase, sputtering rate gradually decreased;h-BN grain in BN/Si O2 composite material was more easily than fused quartz and cristobalite sputtered, and c-BN/Si O2 composite materials was sputterred, fused quartz coated h-BN grain is sputterred first, and then c-BN grain due to debonding and separation with fused quartz substrate, thereby causing mess loss to the whole materials.更多还原