电参数对基体温升、Ti镀层组织与性能的影响

发布时间：2018-04-11 03:34

  本文选题：离子镀术 + 电数　； 参考：《西安理工大学》2017年硕士论文

【摘要】：针对离子镀技术沉积镀层过程中基体温度持续升高这一客观事实,本文提出以金属热处理中淬-回火转变的理论为基础,对基体温升和沿基体纵深方向的温度分布进行表征。通过改变电场环境和电源供给模式,在淬火态GCr15、淬火态40CrNiMoA基体上沉积纯金属Ti镀层,讨论电参数对基体温升和温度分布的影响,并进一步考察镀层组织和性能的变化,探寻不同钢质基体承载能力和镀层组织结构的良好配合。研究结果表明:同一靶功率密度下,基体沿纵深方向的温度分布先直线减小,然后缓慢减小,最后保持不变。随着靶功率密度的提高,基体沿纵深方向的温度整体升高,基体温升极限逐渐增大,GCr15基体由160 ℃增大到441 ℃,40CrNiMoA基体由305 ℃增大到526 ℃。同时,靶功率密度增大,与基体温升综合作用,使得镀层晶化程度增强,择优取向由(100)晶面转变为(110)晶面,平均晶粒尺寸由9.3 nm显著增大到22.5 nm,表面平整度先增大后减小,且镀层内应力为压应力,在基体温升极限大于300 ℃之后随着晶格微观缺陷的消除而松弛。对于回火温度高的40CrNiMoA基体,直流电场环境下,靶功率密度为97.50W/cm2(靶电流为7.5A)时,未出现基体软化,且此时,气体放电处于辉弧过渡区间,镀层平均晶粒尺寸增大受到抑制,致密度较高,表面粗糙度最小,因而实现了基体承载能力和镀层组织结构的良好配合,并且由于内应力的松弛,此时沉积速率可达42.56nm/min;对于具有低回火温度的GCr15基体,直流电场环境下,靶功率密度低至11.89 W/cm2,恰好避免基体软化,脉冲电场环境下,脉冲峰值电流15 A、脉宽2 ms、脉冲频率50 Hz时,实现了对基体温升的有效控制,同时,镀层颗粒细小、光滑平整、致密度较好,且硬度5.9 GPa、塑性指数0.670,均呈现较高水平,结合强度满足要求,达到了工艺设计的目的。
[Abstract]:In view of the objective fact that the substrate temperature increases continuously during the deposition of the coating by ion plating, the temperature rise of the substrate and the temperature distribution along the depth of the substrate are characterized on the basis of the theory of quenching and tempering transition in metal heat treatment.By changing the electric field environment and power supply mode, pure Ti coating was deposited on quenched GCr15 and quenched 40CrNiMoA substrates. The effect of electrical parameters on the temperature rise and temperature distribution of the substrate was discussed, and the microstructure and properties of the coating were further investigated.To explore the different steel substrate bearing capacity and coating structure of good cooperation.The results show that at the same power density, the temperature distribution of the matrix along the depth decreases in a straight line, then slowly decreases, and finally remains unchanged.With the increase of the power density of the target, the temperature of the matrix along the depth direction increases as a whole, and the temperature rise limit of the matrix increases gradually from 160 鈩，

本文编号：1734265