高强度微晶碳化硼陶瓷的研究
来源期刊:中南大学学报(自然科学版)1986年第4期
论文作者:王零森
文章页码:65 - 70
关键词:碳化硼; 特种陶瓷; 热压; 微晶; 晶粒长大
Key words:Boron carbide; Special ceramic; Hot-pressing; Microcrystal; Grain-growth
摘 要:本研究在保证碳化硼粉末充分热致密化的前提下,控制了晶粒长大,从而获得了高强度的微晶碳化硼制件。研究中采用硼酸碳热还原法在碳管炉中制得碳化硼粗粉,经振动球磨、酸洗和分级获得了微米级细粉,其化学成分和杂质含量符合国标GB5151-85中PB4CH-1粉末的要求。本研究还进行了添加剂对热压碳化硼晶粒长大影响的实验。实验表明:硼的加入不仅降低了热压温度,而且有效地控制了晶粒长大,用同种粉末和工艺,晶粒度由6.00μm降至3.72μm。在普通烧结中,少量碳的加入显示了很好的烧结活化作用,但碳对热压没有显示积极的效果。氧化钐的加入明显促进晶粒长大,在相同条件下,晶粒度高达8.06μm。本研究制得的成品由于充分保证了热致密化,故其热压坯晶界强度高,断口晶粒细且均匀,抗弯强度与晶粒度之间的关系符合Osipov建立的方程:σ=σ0+Kd-1/2。其性能达到或超过了文献报导的最好水平。主要性能为:抗弯强度:578-585MPa;克努普硬度(负荷100g):2800—3000km/mm2;孔隙度:<0.5%;平均晶粒度:1—2.5μm;比重:2.49—2.51g/cm3。
Abstract: The superfine boron carbide powder has been obtained by vibratory milling the coarsepowder, which was produced by the reduction of boric acid with carbon in a carbon tubefurnace. The ground powder was acid-washed and classificated. An advanced high strengthmicrocrystallite boron carbide material was produced by using this powder. Its main proper-ties are as follows: specific density: 2.49--2.51g/cm3; micro-hardness (Knoop): 2800--3000kg/mm2: porosity<0.5%; average grain size: 1--2.5μm; transverse rupture strength: 578-585 MPa.