High pressure synthesis of new super hard materials in the boron suboxide system and their functional evaluation

低氧化硼体系高压合成新型超硬材料及其功能评价

基本信息

批准号：
12450273
负责人：
ITOH Hideaki
金额：
$ 8.32万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

New super-hard materials in the boron suboxide system, which contains oxygen atom or light mmetals in the cavity of the rhombohedral unit cell of icosahedral boron clusters, were sintered in composite with other super-hard material under high pressure. The mechanical properties of these composites were investigated along with their chemical and electrical properties. The main results and conclusions in the project term were summarized as follows.1. High pressure sintering of boron suboxide (B_6O) and its composite with diamondB_6O is known as a super-hard material with high chemical stability and also a target material for thermoelectric conversion recently. However, this material is so brittle and difficult to sinter that its actual application as an industrial material is delayed. In the present study, we prepared the sintered compact of B_6O by high pressure sintering of B_6O powder synthesized from B_2O_3 and amorphous boron, and elucidated the mechanical and thermal properties of B_6O single phase sintered compact. In order to enhance the fracture toughness of the compact without decreasing its hardness, the binary composite system of B_6O and diamond was investigated. In case of using fine-grained diamond powder, a superl-hard composite with an increased fracture toughness was prepared and its electrical conductivity at room temperature was as high as the magnitude of 10^<-3> S/cm.2. High pressure sintering of AlMgB_<14> and its composite with other super-hard materialAlMgB_<14> is also a super-hard material with analogous crystal structure to B_6O and expected to exhibit higher mechanical strength. Single phase sintered compact of AlMgB_<14> was prepared originally under high pressure using the powder synthesized in our laboratory. This compact showed the hardness as high as B_6O, though the fracture toughness was similarly low. Presentation of the composite systems of AlMgB_<14> with B_6O or TiB_2 resulted in higher hardness, hut lower fracture toughness.

硼亚氧化物系统中的新的超硬材料在二十面体硼簇簇的菱形型单位细胞的腔中包含氧原子或轻晶状体，与其他超硬压材料合成。研究了这些复合材料的机械性能及其化学和电性能。项目术语中的主要结果和结论总结如下1。硼亚氧化物（B_6O）及其与DiamondB_6O的复合材料的高压烧结被称为具有高化学稳定性的超硬材料，并且最近也是热电转换的目标材料。但是，这种材料是如此脆弱且难以烧结，以至于其作为工业材料的实际应用被延迟了。在本研究中，我们通过从B_2O_3和无定形硼合成的B_6O粉末的高压烧结来制备B_6O的烧结，并阐明了B_6O单相烧结的紧凑型B_6O的机械和热性质。为了增强紧凑型的断裂韧性而不会降低其硬度，研究了B_6O和Diamond的二元复合系统。如果使用细颗粒的钻石粉，则制备具有裂缝韧性增加的超级固定复合材料，其在室温下的电导率高达10^<-3> s/cm.2。 ALMGB_ <14>的高压烧结及其与其他超硬性物质的复合材料也是一种具有类似晶体结构的超硬质材料，可表现出更高的机械强度。使用实验室中合成的粉末，最初在高压下制备了ALMGB_ <14>的单相烧结。这种紧凑的硬度表现出与B_6O一样高的硬度，尽管断裂韧性类似。用B_6O或TIB_2的ALMGB_ <14>复合系统的呈现导致硬度更高，小屋较低的断裂韧性。