(福州大學(xué) 材料科學(xué)與工程學(xué)院， 福州 350002)
摘 要: 研究了WO3、 Co3O4和石墨混合粉末經(jīng)高能球磨活化后再分步進(jìn)行還原和碳化反應(yīng)制備超細(xì)WC-Co粉末的過(guò)程。 結(jié)果表明： 球磨30 h后， 粉末粒徑達(dá)到70~100 nm。 450~700 ℃溫度范圍內(nèi)球磨粉在流動(dòng)H2和Ar混合氣體中經(jīng)2 h還原時(shí)， 隨著還原溫度的升高， WO3還原反應(yīng)順序?yàn)閃O3→WO2.9→WO2.72→WO2→W， 700 ℃時(shí)可實(shí)現(xiàn)完全還原； Co3O4在450 ℃完全還原為Co， 隨著溫度的進(jìn)一步升高和時(shí)間的延長(zhǎng)， Co與W反應(yīng)轉(zhuǎn)變?yōu)镃o3W； 最終還原產(chǎn)物由W、 Co、 Co3W和石墨組成；在700~1 000 ℃溫度范圍內(nèi)還原粉在流動(dòng)Ar中碳化時(shí)，隨著碳化溫度的升高， 碳化反應(yīng)按W(Co3W)→Co6W6C→Co3W3C→W2C→WC的順序進(jìn)行，在900 ℃下還原粉在2 h內(nèi)可完全碳化， 得到WC顆粒尺寸約為200~300 nm的WC-Co復(fù)合粉末。
關(guān)鍵字: WC-Co； 高能球磨； 還原； 碳化
integrated mechanical and
thermal activation process
（ School of Materials Science and Engineering,
Fuzhou University, Fuzhou 350002, China）
Abstract: Synthesis of ultrafine WC-Co powders was investigated using WO3, Co3O4 and graphite powders as starting materials by high energy ball milling followed by reduction and carburization. The results show that particle sizes of powder mixtures milled 30 h are in the range of 70-100 nm. When the milled mixture is reduced in a flowing gas mixture of H2 and Ar at different temperatures ranging from 450 to 700 ℃ for 2 h, the reaction sequence of WO3 to W appears as WO3→WO2.9→WO2.72→WO2→W with the increase of temperature, and WO3 reduction completes at 700 ℃. Reduction reaction of Co3O4 to Co can be finished in 2 h at 450 ℃ and the reduced Co keeps reacting with W to transform into Co3W with the increase of reduction temperature and time. The final product of reduction reaction is composed of W, Co, Co3W and graphite. The reduced mixture is carburized in a flowing Ar in temperature range of 700-1 000 ℃, carburization reaction takes place following the routine W(Co3W)→Co6W6C→Co3W3C→W2C→WC, and the carburization reaction completes at 900 ℃ in 2 h. The size of the WC grain in the final WC-Co composite powders is in the range of 200-300 nm.
Key words: WC-Co; high energy ball milling; reduction; carburization
