【摘要】：以平均粒徑40 nm的W粉為原料,采用"預(yù)碳化+二段碳化"的階段碳化工藝制備出平均粒徑為82 nm的近球形WC粉。利用X射線衍射(XRD)、場發(fā)射掃描電鏡(FE-SEM)、BET比表面積分析儀等測試方法,分別對碳化產(chǎn)物的物相組成、形貌和粒徑大小進(jìn)行表征。研究了不同預(yù)碳化溫度和二段碳化溫度對WC粉粒徑和形貌的影響,并對階段碳化的機(jī)制進(jìn)行了討論。結(jié)果表明,在800~1000℃范圍內(nèi),WC粉的平均粒徑隨預(yù)碳化溫度升高呈先減小后增大的變化趨勢,在900℃達(dá)到最小值。WC粉的平均粒徑隨二段碳化溫度升高而增大,當(dāng)二段碳化溫度高于1250℃時,WC粉的平均粒徑顯著增大。碳化過程中WC顆粒的長大主要是由碳化初期納米W顆粒的燒結(jié)合并引起的。低溫預(yù)碳化能夠在W粉顆粒表面形成一定厚度的WC層,阻礙W粉顆粒發(fā)生燒結(jié)合并,從而有效抑制WC粉的長大。階段碳化制備納米WC粉的最佳工藝為:預(yù)碳化溫度900℃,二段碳化溫度1150~1200℃。
[Abstract]:Using W powder with average particle size of 40 nm as raw material, the near spherical WC powder with average particle size of 82 nm was prepared by the stage carbonization process of "pre-carbonization two-stage carbonization". The phase composition, morphology and particle size of carbonized products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), BET specific surface area analyzer). The effects of different pre-carbonization temperature and two-stage carbonization temperature on the particle size and morphology of WC powder were studied, and the mechanism of stage carbonization was also discussed. The results show that the average particle size of WC powder decreases first and then increases with the increase of pre-carbonization temperature in the range of 800 鈩，

本文編號：2465879