磁控溅射CrNx薄膜的制备及性能研究

【作者】 徐根；

【导师】 刘雄飞；

【作者基本信息】 中南大学 ， 电子科学与技术， 2012， 硕士

【摘要】 本文采用磁控溅射镀膜设备及工艺,在Q235钢表面制备了CrNx镀膜层。对不同工艺条件下制备的样品进行硬度测试、金相组织观察、XRD的测试以及耐摩性和耐蚀性的测试。测试表明：随着CrNx镀膜层厚度增加,镀膜层择优取向生长逐步由{200}转为{111},表面“胞状”组织形貌愈加明显,且向外“突起”,硬度较高,外观也比较均匀光滑,无脱落现象。随着工作气压的升高,Cr、N原子个数比逐渐增大；保温温度越高,CrNx镀膜层表面Cr、N原子个数比越大；Ar／N2流量比为3：2时,Cr、N原子个数比最接近1：1,表面Cr、N原子个数比越接近1：1,CrNx镀膜层性能越好。CrNx镀膜层表面形貌为“胞状”组织,颗粒致密均匀,结合强度高。在相同磨损条件下,CrNx镀膜层相对磨损速度很小,耐磨性较未处理的Q235钢试样提高。随砂粒度增加,CrNx镀膜层相对磨损速度增大；载荷越大,CrNx镀膜层磨损质量损失越多,相对磨损速度越大。镀膜层的磨损失效形式主要是碎裂与剥落。镀膜处理样与原样相比,在酸性溶液中具有更低的活性溶解速度和更优的钝化性能；镀膜层未改变材料在中性溶液中的阴极反应历程,阳极塔菲尔斜率降低,阳极极化率增加,但只是发生在缺陷处。防护特性在于：它减小了腐蚀介质在电极表面的集聚,阻挡了反应物和腐蚀产物的传输,增加了回路电阻,表面缺陷率是决定处理后耐蚀性的重要因素。研究表明镀膜层失效机制是：侵蚀性离子首先通过缺陷传输和与Cr钝化膜产生络合反应穿透钝化膜,到达了基体,同时随着腐蚀的深入,镀膜层与基体的结合力下降,逐步脱落,丧失对基体的保护作用。镀膜层的腐蚀机理是：阳极反应过程都是先失电子后钝化,阴极反应在中性溶液中为吸氧反应,改性层表面生成的化合物有效的阻碍了腐蚀介质对基体表面的阳极溶解作用,抑制了腐蚀速度的加剧。更多还原

【Abstract】 This paper adopts magnetron sputtering film coating equipment and technology, CrNx coating layer can be obtained on Q235steel surface. Hardness test, microstructure observation, XRD test, abrasion resistance and corrosion resistance test are taken for samples which prepared under different Process conditions.Experimental results show, As thickness of CrNx coating increases, coating layer gradually preferred geting selected to grow into{111} by {200}. With growth orientation of high hardness and better wearability CrNx coating layer of111, shall obtain preferred orientation with{the CrNx phase). Surface "cellular" organization morphology, and became apparent to the "bumps" trend increase. When CrNx coating layer surface morphology homogeneously dense "cellular" organization, hardness is taller, the exterior also is evener smooth, without falls off phenomenon. Source voltage and seepage Cr stage sample voltage, synthetic phase sample voltage, synthetic stage holding time on CrNx coating layer surface Cr, N atomic number of influence is not big, than work pressure, insulation temperature and Ar/N2flow compare the influence is bigger. Along with the work pressure increases, Cr, N atomic number than increase gradually; Heat preservation, the higher the temperature CrNx coating layer surface Cr, N atomic number than bigger; Ar/N2flow, than for three-to-two Cr, N atomic number than most close1:1, surface Cr, N atomic number approximates to1:1, better than the performance of CrNx coating layer. CrNx coating layer surface morphology is "cellular" organization, a particle density even, combined with high strength. In the same wear conditions, CrNx coating layer relative wear speed minimum, wearability are unprocessed of Q235steel sample improved. With sand CrNx coating layer increased, degree of relative wear speed increases; The larger the load CrNx coating layer, the more quality loss, wear relatively wear with greater speed. Coating layer failure form is mainly the wear fractured and spalling.Coating processing, compared with the original sample in acidic solution with lower activity dissolution rate and better passivation performance; Coating layer unchanged materials in neutral solution of the cathode reaction process, anode tower phil slope reduced, anode polarization rate increase, but just happens in the defect place. Protective character depends on:it reduced the corrosive medium in the electrode surface of the cluster, blocking the reactant and corrosion product transmission, increased the loop resistance, the surface defects is decided after the corrosion resistance of handling important factors. Research shows that coating layer failure mechanism is:erosive ion first through the defect transmission and and Cr passivation membrane penetration passivating film produced complexation reaction to the substrate, at the same time as corrosion deeply, coating layer and the base off the adhesion strength of the drop, gradually, the protective effects of loss of substrate. Coating layer, the corrosion mechanism of anode reaction process is:after all is lost, the first electronic cathode reaction in neutral passivation solution for universitier reaction, modified layer surface generated compounds effective hindered the corrosive medium to dissolve the matrix surface effect, inhibit the anode corrosion rate are intensifying.更多还原