High Pressure Sintering of Super-hard Boron Suboxide and Evaluation of Sintered Compacts

超硬低氧化硼的高压烧结及烧结体的评价

基本信息

批准号：
09650732
负责人：
ITOH Hideaki
金额：
$ 1.98万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650732/
关键词：
Boron Suboxide Super-hard Boron Oxide High Pressure Sintering Super-hard Material Sintered Composite

项目摘要

Hexaboron oxide (B_6O) is one of the super-hard boron compounds which has a microhardness comparable to diamond or cubic boron nitride, and is expected to an actual application to cutting tools or nozzle parts. However, B_60 is so difficult to sinter and to densify the compact that its mechanical or thermal property is less known so far. In the present paper, we prepared B_60 sintered compact in full density by high pressure and high temperature treatment of sinterable B_60 powder which was synthesized in our laboratory. Then, we investigated the mechanical and thermal properties of the sintered compacts and evaluated the possibility of application to various tools.1.Synthesis and characterization of B_60 powderB_60 powder was synthesized by heat treatment (1350ﾟC, 4 h) of the mixture of amorphous B_20_3 and boron (1 : 16 in mol ratio) in an pure argon stream. The synthesized B_60 powder was observed by SEM to comprise crystalline and dispersible particles with 1.2-1.4 mu m diameters.2 … More .High pressure sintering of B_6O powder and the mechanical or thermal properties of the sintered compactAn optimum sintering condition of the vacuum treated B_60 powder was investigated using the girdle-type high pressure apparatus. A single phase B_6O sintered compact was prepared by the high pressure and temperature treatment at 5 GPa, 1700ﾟC and 20 min. The relative density and Vickers microhardness were 97% and 3400 kg/mm^2, respectively. TG-DTA analyses exhibited that B_60 sintered compact had an oxidation resistance higher than B4C, and a mild oxidation proceeded up to 1000ﾟC accompanied by a formation of protective layer of liquid B_2O_33.Preparation of B_60-based sintered composites and their possibility for application to toolsSintered composites in the B_60-B_4C system or B_60-cBN system were prepared in order to increase the toughness of B_60 sintered compact. High pressure and temperature treatments of the vacuum treated mixed powder of B_60 and B_4C/cBN were carried out under the conditions of 3-8 GPa, 150O-1800ﾟC and 15-30 min. Maximum values of microhardness and fracture toughness in both systems were 4600 kg/mm^2 and 1-1.8MNm^<-3/2>, respectively. Less

六硼氧化物(B_6O)是一种超硬硼化合物，其显微硬度可与金刚石或立方氮化硼相媲美，有望在切削工具或喷嘴部件中实际应用。然而，B_60很难烧结和加工。致密化压坯，其机械或热性能目前尚不清楚。在本文中，我们通过高压和高温处理制备了全致密的B_60烧结体。然后，我们研究了本实验室合成的可烧结B_60粉末的机械性能和热性能，并评估了其在各种工具中的应用可能性。1.B_60粉末的合成和表征B_60粉末通过热处理（1350ﾟ）合成。 C，4小时）无定形B_20_3和硼的混合物（摩尔比1:16）在纯氩气中SEM 观察到合成的 B_60 粉末包含直径为 1.2-1.4 μm 的结晶和可分散颗粒。2 … 更多。B_6O 粉末的高压烧结以及烧结体的机械或热性能真空的最佳烧结条件采用束带式高压处理装置对B_60粉末进行了研究，通过高压高温处理制备了单相B_6O烧结体。 5 GPa、1700℃、20 min 时，相对密度和维氏显微硬度分别为 97% 和 3400 kg/mm^2，表明 B_60 烧结体具有比 B4C 更高的抗氧化性能。氧化进行至1000°C，并形成液体保护层B_2O_33.B_60基烧结复合材料的制备及其在工具中应用的可能性为了提高B_60烧结体的韧性，制备了B_60-B_4C系统或B_60-cBN系统中的烧结复合材料，并进行了真空高压和高温处理。 B_60和B_4C/cBN的混合粉末在3-8 GPa的条件下进行， 150O-1800ﾟC和15-30 min，两个体系的显微硬度和断裂韧性最大值分别为4600 kg/mm^2和1-1.8MNm^<-3/2>。