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通过静态浸泡腐蚀和动电位极化两种方法,研究了Mo2C对Ti(C,N)基金属陶瓷在NaOH溶液中腐蚀性能的影响。实验结果表明:Ti(C,N)基金属陶瓷的耐蚀性明显优于WC-Co硬质合金;添加Mo2C可以大幅度提高Ti(C,N)基金属陶瓷的机械性能,硬度从91.2到94.0 HRA和抗弯强度从930到1 350 MPa,但会降低金属陶瓷的耐蚀性能;由于Mo2C的加入,会使金属陶瓷的动电位极化曲线出现两个钝化区,但是两个钝化区域的电流均未达到真正的钝化电流(10-5A/cm2),因而这些钝化现象均为伪钝化;在经动电位极化后的试样表面,粘结相Ni和白色的内环相均会被腐蚀,其中内环相为富Mo的(Mo,Ti)(C,N)固溶体,其耐腐蚀性较未溶的Ti(C,N)芯更差。随着Mo2C添加量的提高,内环形相的厚度随之会增加,从而降低了Ti(C,N)基金属陶瓷的耐蚀性能。
The effects of Mo2C on the corrosion behavior of Ti (C, N) -based cermets in NaOH solution were investigated by static immersion corrosion and potentiodynamic polarization. The experimental results show that the corrosion resistance of Ti (C, N) -based cermets is better than that of WC-Co cemented carbides. The addition of Mo2C can greatly improve the mechanical properties of Ti (C, N) -based cermets with hardness ranging from 91.2 to 94.0 HRA and flexural strength from 930 to 1 350 MPa, but will reduce the corrosion resistance of cermets; due to the addition of Mo2C, there will be two passivation zones of the potentiodynamic polarization curve of the cermet, but two passivation The region of the current did not reach the true passivation current (10-5A / cm2), and therefore these passivation are pseudo-passivation; after the polarization potential of the sample surface, Ni and white binder phase The ring phase will be corroded, and the inner ring phase is Mo-rich (Mo, Ti) (C, N) solid solution with worse corrosion resistance than the undissolved Ti (C, N) With the increase of Mo2C content, the thickness of the inner annular phase increases, which decreases the corrosion resistance of Ti (C, N) -based cermets.