WC/W_2C_P在NiCrBSi合金中的分解机理及其表面渗碳改性  

Dissolving Mechanism of the WC/W_2C_P in Ni Cr BSi Alloy and Surface Modification for the WC/W_2C_P by Carburizing

作　　者：侯书增[1] 鲍崇高[1] 李烨飞[1] 

机构地区：[1]西安交通大学金属强度国家重点实验室,陕西西安710049

出　　处：《稀有金属材料与工程》2015年第7期1772-1776,共5页Rare Metal Materials and Engineering

基　　金：中央高校基本科研业务费专项资金;陕西省自然科学基金(2013JQ6009);高等学校博士学科点专项科研基金新教师类资助课题(20130201120002)

摘　　要：为了抑制铸造碳化钨颗粒(WC/W2C P)在复合材料制备过程中的过度分解,利用SEM、EDS和XRD等测试手段对WC/W2C P在Ni Cr BSi合金中的分解机理及其表面改性渗碳处理进行了研究。结果表明,铸造碳化钨由WC和W2C两相组成,在Ni Cr BSi合金中WC相比W2C相具有更好的化学稳定性。在熔烧法制备WC/W2C P增强Ni Cr BSi基复合材料涂层的过程中,基体熔液和WC/W2C P发生元素互扩散;WC/W2C P中的化学稳定性差的W2C相与从基体熔液中扩散过来的Ni、Cr等元素反应生成了富W、Ni的碳化物,而化学稳定性好的WC相几乎完整的保留下来;基体中的Ni、Cr元素与从WC/W2C P中扩散过来的W、C元素形成了富W、Ni、Cr的碳化物在凝固过程中析出。经渗碳表面改性后,WC/W2C P表面形成了化学稳定性好的WC壳层,该壳层能有效抑制WC/W2C P在基体中的扩散分解,减少基体中碳化物的析出。In order to restrain the excessive dissolving of the cast tungsten carbide particles（WC/W2 CP） used in the production of composites, the dissolving mechanism of the WC/W2 CP in Ni Cr BSi alloy and the surface modification for the WC/W2 CP by carburizing were investigated by SEM, EDS, XRD etc.The results show that the cast tungsten carbide consists of WC and W2 C, and WC has a higher chemical resistance in molten Ni Cr BSi than W2 C.Interdifusion of elements occurred between the molten matrix and the particles during the preparation of WC/W2 CP reinforced Ni Cr BSi composite coating by fusion sintering.W2 C in WC/W2 CP reacted with Ni, Cr and other elements diffusing from molten matrix to form W, Ni-rich carbides, while WC in WC/W2 CP remained mostly intact.Elements such as Ni and Cr in matrix reacted with W and C diffusing from WC/W2 CP to form W, Ni, Cr-rich carbides and precipitated from the melt during cooling.After carburization, the cast tungsten carbide particles had a shell of WC, which can effectively restrain dissolving of the particles, and reduce carbide precipitations in the matrix.

关 键 词：渗碳处理 分解机理 铸造碳化钨 NICRBSI 

分 类 号：TB33[一般工业技术—材料科学与工程] TG156.81[金属学及工艺—热处理]