热压法制备的(Mo_(1-x)Nb_x)_5Si_3合金组织及抗腐蚀性能  

Microstructure and corrosion resistance of (Mo_(1-x)Nb_x)_5Si_3 silicide alloy prepared by hot-pressing

作　　者：陈辉[1] 马勤[1] 赵雪[1] 徐柯[1] 

机构地区：[1]兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,兰州730050

出　　处：《粉末冶金材料科学与工程》2011年第3期386-391,共6页Materials Science and Engineering of Powder Metallurgy

基　　金：甘肃省自然科学基金资助项目(3ZS061-A25-038);兰州理工大学特色研究方向资助项目(T200304)

摘　　要：以Mo粉、Nb粉、Si粉为原料,采用热压法制备(Mo1-xNbx)5Si3(x=0,0.2,0.4)难熔金属硅化物合金,利用电化学测试及盐酸浸泡腐蚀实验,研究该合金在浓度为1 mol/L的HCl溶液中的腐蚀行为以及Nb含量对合金组织和耐蚀性的影响。结果表明,随Nb含量增加,(Mo1-xNbx)5Si3合金晶粒细化,相对密度和组织均匀性提高,x=0.4时晶粒尺寸和相对密度分别为44.1 nm和96.1%;阳极极化曲线表现出钝化-溶解-钝化的二次钝化行为;由于(Mo1-xNbx)5Si3合金高的化学稳定性及其表面形成MoO2、SiO2等钝化膜,因此该合金具有非常优异的耐HCl溶液腐蚀性能,且随着Nb含量增加,耐腐蚀性提高。Mo5Si3、Mo4NbSi3和Mo3Nb2Si3在0.1 mol/L的盐酸溶液中平均浸泡腐蚀速率分别为0.064、0.039和0.020 mm/a,远低于0Cr18Ni9不锈钢的平均腐蚀速率(12.04 mm/a)。Using Mo,Nb and Si elemental powders as raw materials,refractory metal silicide alloys（Mo1-xNbx）5Si3（x=0,0.2,0.4） were designed and fabricated by hot-pressing sintering technology.Both the corrosion behavior of（Mo1-xNbx）5Si3 intermetallic alloys in 1 mol/L HCl solusion and the effect of Nb content in alloys on the structure and corrosion resistance of the alloys were investigated by polarization curve and immersion corrosion.The results show that the grain size decreases,relative density and organization uniformity increases with the increase of Nb content in the alloys.The crystallite size and relative density of the Mo3Nb2Si3 are 44.1nm and 96.1%,respectively.The second passivation behavior of anodic polarization curves show passivation,dissolution and passivation again.The alloys have excellent corrosion resistance in 1 mol/L HCl solution owing to the formation of passivation film of MoO2 and SiO2 in surface of the alloys and the high chemical stability of（Mo1-xNbx）5Si3 intermetallic.The corrosion resistance of the alloys improves with the increase of Nb content.The immersion corrosion rate of Mo5Si3,Mo4NbSi3 and Mo3Nb2Si3 are 0.064 mm/a,0.039 mm/a and 0.020 mm/a,respectively and are greatly lower than that of traditional 0Cr18Ni9 stainless steel corrosion resistant materials which is 12.04 mm/a in 0.1 mol/L hydrochloric acid solution.

关 键 词：MO5SI3 腐蚀 金属硅化物 极化曲线 

分 类 号：TB331[一般工业技术—材料科学与工程] TG174[金属学及工艺—金属表面处理]