Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第15卷    第6期    总第75期    2005年6月

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文章编号:1004-0609(2005)06-0929-06
机械与热综合活化法制备超细WC-Co粉末
刘紫兰, 李 强, 张钦钊, 黄向东

(福州大学 材料科学与工程学院, 福州 350002)

摘 要:  研究了WO3、 Co3O4和石墨混合粉末经高能球磨活化后再分步进行还原和碳化反应制备超细WC-Co粉末的过程。 结果表明: 球磨30 h后, 粉末粒径达到70~100 nm。 450~700 ℃温度范围内球磨粉在流动H2和Ar混合气体中经2 h还原时, 随着还原温度的升高, WO3还原反应顺序为WO3→WO2.9→WO2.72→WO2→W, 700 ℃时可实现完全还原; Co3O4在450 ℃完全还原为Co, 随着温度的进一步升高和时间的延长, Co与W反应转变为Co3W; 最终还原产物由W、 Co、 Co3W和石墨组成;在700~1 000 ℃温度范围内还原粉在流动Ar中碳化时,随着碳化温度的升高, 碳化反应按W(Co3W)→Co6W6C→Co3W3C→W2C→WC的顺序进行,在900 ℃下还原粉在2 h内可完全碳化, 得到WC颗粒尺寸约为200~300 nm的WC-Co复合粉末。

 

关键字:  WC-Co; 高能球磨; 还原; 碳化

Synthesis of ultrafine WC-Co composites by
integrated mechanical and
thermal activation process
LIU Zi-lan, LI Qiang, ZHANG Qin-zhao, HUANG Xiang-dong

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

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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