CaB2O4掺量对烧结后hBN结构及摩擦性能的影响

Effects of CaB2O4 Contents on the Microstructure and Tribological Properties of Sintered hBN

为了促进hBN的结晶生长,降低其摩擦系数,研究了CaB2O4掺量对烧结后hBN结构和摩擦性能的影响。在hBN中加入CaB2O4作为烧结助剂,在N2气氛下于2000℃保温5h对不同CaB2O4掺量的hBN进行了烧结,采用XRD、SEM和摩擦磨损试验机对烧结后hBN的物相组成、显微结构和摩擦性能进行了表征,并探讨了烧结后hBN的摩擦磨损机理。结果表明:烧结后,hBN晶体呈片状。随着CaB2O4掺量由0%增加到15%,hBN晶体直径由0.5~2μm逐渐增大到2~4.5μm;晶体厚度由100nm增加到200nm,说明在N2气氛下,2000℃,保温5h时,CaB2O4的加入可以促进hBN的结晶生长。hBN块体的摩擦系数随着CaB2O4掺量的增加有下降的趋势。随着温度从室温增加到800℃,烧结后hBN的摩擦系数先增大后减小。

The effects of CaB2O4 contents on the microstructure and tribological properties of sintered hBN were studied,in order to promote crystal growth of hBN and decrease it’s friction coefficient. The CaB2O4 was added into hBN as sintering additive. Then,the hBN with different CaB2O4 contents were sintered at 2000 ℃ for 5 h in N2 ambience. The phase analysis,microstructure and tribological properties of the sintered hBN were studied by XRD,SEM and high-temperature tribometer. The tribological mechanism of sintered hBN was also discussed. The results show that the sintered hBN has a plate-like shape. The diameter of sintered hBN increases from 0.5-2 μm to 2-4.5 μm,meanwhile the thickness increases from 100 nm to 200 nm,with the increase of CaB2O4 content from 0%to 15%,which indicate that the addition of CaB2O4 as sintering additive can effectively promote crystal growth of hBN at 2000 ℃ for 5 h in N2 ambience. The friction coefficient of sintered hBN decreases with the increase of CaB 2O 4 content. As the temperature increases from room temperature to 800 ℃,the friction coefficient of sintered hBN firstly increases and then decreases.