原位热压合成高纯Cr_2AlC块体材料及其腐蚀性能的研究  

In-situ Hot Pressing Synthesis and Corrosion Properties of High Pure Cr_2AlC

作　　者：宋京红[1] 梅炳初[2] 王敬平[2] 

机构地区：[1]武汉理工大学材料研究与测试中心,武汉430070 [2]武汉理工大学材料复合新技术国家重点实验室,武汉430070

出　　处：《无机材料学报》2010年第4期419-423,共5页Journal of Inorganic Materials

基　　金：国家自然科学基金(20771088)

摘　　要：采用原位热压烧结工艺,以Cr3C2、Cr和Al粉为原料制备Cr2AlC块体材料.采用X射线和扫描电镜(SEM)对制备的样品进行表征.利用差热法对反应过程进行了研究,以失重法研究Cr2AlC在酸和碱溶液中的腐蚀性能.结果表明,以n(Cr3C2)∶n(Cr)∶n(Al)=0.5∶0.5∶1.2配比,1350℃,30MPa压力热压2h得到高纯Cr2AlC块体,其合成过程首先为Al的溶化,在700℃时Cr与Al生成Cr5Al8,最后Cr5Al8与Cr3C2反应生成Cr2AlC.样品断面的扫描照片显示,烧结试样呈板状和片状结晶形貌特征,平均粒径为6.4μm.除在浓H2SO4和浓HCl中失重较大外,Cr2AlC在其它溶液中均表现较低的失重.样品浸泡在浓和稀的NaOH溶液150d几乎没有质量损失,腐蚀率仅为0.4和0.7μm/a.Cr2AlC bulk material was prepared in-situ by hot pressing sintering using Cr3C2,Cr and Al as the starting materials.The samples were characterized using X-ray diffraction（XRD） and scanning electron microscope（SEM）.The reaction process was investigated by means of differential scanning calorimetry（DSC）.The corrosion properties of Cr2AlC in the acid and alkali solutions were obtained by weight loss method.The XRD result shows that high purity Cr2AlC bulk material can be synthesized by hot pressing with n（Cr3C2）∶n（Cr）∶n（Al）=0.5∶0.5∶1.2 at 1350℃ for 2h under 30MPa.The XRD patterns in different temperatures suggest that the reaction process of starting materials is that Al melts at first,then Cr5Al8 generates at 700℃,Cr2AlC is produced with the temperature elevation by the reaction of Cr5Al8 and Cr3C2 at last.SEM images of fracture faces of the sintered sample show the laminated and well plate-shaped grains with a mean particale size of 6.4μm.Cr2AlC exhibits low weight loss except immersion in the concentrated H2SO4 and HCl solutions.The weight loss is negligible after immersing samples in the concentrated and dilute NaOH solutions for 150d and the corrosion rates are only 0.4 and 0.7μm/a,respectively.

关 键 词：热压 铬铝化碳 腐蚀性能 失重法 

分 类 号：TB321[一般工业技术—材料科学与工程]