不同温湿度条件下微米硼的氧化过程研究

Oxidation Process of Micron Boron under Different Temperature and Humidity Conditions

目的 探究不同温湿度条件下微米硼的氧化层结构特征。方法 利用高温水浴浸泡处理去除原料微米硼的表面氧化层,然后在恒温恒湿条件下对微米硼进行加速氧化,利用扫描电子显微镜、透射电子显微镜和X射线光电子能谱对加速氧化后硼颗粒的氧化层厚度及组成进行分析,总结表面氧化层结构及成分组成变化规律,揭示温湿度条件下微米硼的氧化机制。结果 微米硼经高温水浴浸泡处理后,表面氧化层去除率达到50%。随着加速氧化时间的延长,硼颗粒氧化层的厚度逐渐增大,由内向外硼颗粒表面可以用B-B_(x)O_(y)-B_(2)O_(3)三层结构来表示,B_(x)O_(y)总是伴随着B_(2)O_(3)同时出现的,且随着氧化反应的进行,颗粒表面B_(x)O_(y)的含量将超过B的含量。结论 不同温湿度条件下微米硼的氧化机制为O_(2)向B颗粒内部单向扩散的反应机制,B先与O_(2)反应,形成低氧化物B_(x)O_(y),B_(x)O_(y)进而与O_(2)反应生成B_(2)O_(3)。随着氧化层厚度的增加,O_(2)向B颗粒内部扩散的阻力增大,氧化反应速率随之降低。相比湿度的影响,温度的升高可显著加快硼表面氧化层的形成;温度一定时,湿度的增加可促进硼氧化层的形成。

The work aims to explore the structural characteristics of the oxide layer of micro boron under different tempera-ture and humidity conditions.The surface oxide layer of raw material micron boron was removed by high-temperature water bath soaking treatment,and then accelerated oxidation of micron boron was carried out under constant temperature and humidity conditions.Scanning electron microscopy,transmission electron microscopy,and X-ray photoelectron spectroscopy were used to test the thickness and composition of the oxide layer of boron particles after accelerated oxidation.The changes in surface oxide layer structure and composition were summarized,and the oxidation mechanism of micro boron particles under tempera-ture and humidity conditions was revealed.The results showed that the surface oxide layer of micron boron particles could be removed by 50%after high-temperature water bath soaking treatment.As the accelerated oxidation time prolonged,the thick-ness of the boron particle oxide layer gradually increased.The surface of the boron particles could be represented by a B-B_(x)O_(y)-B2O_(3) three-layer structure from the inside out.B_(x)O_(y) always appeared with B2O_(3) simultaneously,and as the oxidation reaction continued,the content of B_(x)O_(y) on the particle surface exceeded that of B.The oxidation mechanism of micro boron un-der temperature and humidity conditions is a reaction mechanism of unidirectional diffusion of O_(2) into the interior of B parti-cles.B firstly reacts with O_(2) to form B_(x)O_(y),which then reacts with O_(2) to form B2O_(3).As the thickness of the oxide layer increases,the diffusion resistance of O_(2) towards the interior of particle B increases,and the oxidation reaction rate decreases accordingly.Compared to the effect of humidity,an increase in temperature can significantly accelerate the formation of an oxide layer on the surface of boron.When the temperature is constant,an increase in humidity can promote the formation of a boron oxide layer.