TiBN固体自润滑薄膜的PIIID制备工艺及其性能研究

发布时间：2018-03-24 02:32

  本文选题：等离子体浸没离子注入与沉积　切入点：TiBN纳米复合薄膜　出处：《哈尔滨工业大学》2017年博士论文

【摘要】：随着国防装备制造产业的高速发展,一些关键机械零部件必须在高温、高速条件下进行服役,在这些零件表面制备出具有抗高温氧化、低摩擦系数和耐磨损的表面强化层是满足这类工况的关键。传统固体润滑材料,如二硫化钼、类金刚石等,在高温条件下易发生氧化分解,不能满足这类需求。六方氮化硼(h-BN)的抗高温氧化温度上限可达900°C,并在宽温域内均能保持恒定的低摩擦系数,在高温固体润滑领域体现出很大的应用潜力。但是,目前含有h-BN的固体润滑涂层的制备方法主要为粉末冶金或激光熔覆,很难实现精密零件表面的镀膜。通过物理或化学气相沉积技术制备的BN基复合薄膜其氮化硼主要为立方相,不具备低摩擦系数的特征,无法实现高温固体润滑的目的。由于h-BN属于绝缘材料,直接通过阴极弧方法无法形成等离子体,本研究将Ti与h-BN粉末进行混合,通过冷压成型、真空热烧结的方法制备了TiBN复合阴极。研究结果表明,当h-BN含量控制在40wt.%以内时,Ti-BN复合阴极具有良好的导电性能。随着h-BN含量的提高,Ti-BN复合阴极电阻明显增加,且阴极相对密度呈下降趋势。采用等离子体取样质谱仪测量了Ti-BN复合阴极放电等离子体的特征参数,研究了阴极成分、磁导管角度、气压和电流对等离子体分布规律的影响。研究结果表明,Ti-BN复合阴极放电过程形成的等离子体中主要包含Ti~+、Ti~(2+)、BN~+离子等。与45°磁导管相比,这些离子在90°磁导管中的损失率要高1倍左右;当气压在0.1Pa到1.0Pa范围内变化时,Ti~+和BN~+离子密度与气压的关系呈现高斯分布,在0.3Pa时离子密度最高,采用该工作气压有利于提高TiBN纳米复合薄膜的沉积速率;当电流增大时,离子密度明显增加,但是当平均电流提升至14A后,离子密度基本不随电流的增大而增加,而且平均电流的继续提高将导致弧光放电过程中大颗粒数量急剧增加。采用Ti-BN复合阴极以及等离子体浸没离子注入与沉积(PIIID)工艺制备了TiBN纳米复合薄膜。结果显示,随着薄膜中B含量的提高,薄膜内部非晶含量增加,同时纳米晶尺寸减小,红外傅立叶光谱和X光电子能谱分析结果表明,薄膜内的B和N之间化学键的杂化形式是sp~2杂化。高分辨透射电镜结果表明TiBN纳米复合薄膜为非晶包裹纳米晶结构,纳米晶成分主要为Ti N,而非晶成分包括BN和Ti O2等。此外,TiBN纳米复合薄膜断面结构均出现了不同程度的自分层现象,这主要是由于薄膜中纳米晶尺寸变化造成的。随着薄膜中B含量的提高,纳米晶中部分出现了h-BN相。室温条件下所有TiBN薄膜的摩擦系数均较小,介于0.15~0.3之间,而且随着薄膜中BN含量的提高,薄膜摩擦系数逐渐降低,15wt.%含量的Ti-BN复合阴极所制备的薄膜具有最佳的耐磨性能。TiBN纳米复合薄膜的高温氧化实验结果表明,该复合薄膜在低于800℃时仍能保持较低摩擦系数,介于0.2~0.35之间,但薄膜表面出现了明显的氧化物;当温度达到1000℃时,薄膜出现了不同程度的崩裂。
[Abstract]:With the rapid development of national defense equipment manufacturing industry, some of the key mechanical parts must be in high temperature, high speed under the condition of service in these parts of the surface were prepared with high temperature oxidation resistance, low friction coefficient and wear resistant surface strengthening layer is the key to meet these conditions. The traditional solid lubricating material, such as diamond, molybdenum disulfide, etc. that oxidation easily occurs in high temperature conditions, which can not meet the needs of six. Boron nitride (h-BN) high temperature limit oxidation temperature can reach 900 DEG C, low friction coefficient and in a wide temperature range can be kept constant, reflecting the great potential in the field of high temperature solid lubricant. However, solid the lubricant coating containing h-BN preparation method for powder metallurgy or laser cladding coating, it is difficult to achieve precision parts. The surface by physical or chemical vapor deposition technology for preparation of BN composite thin films Mainly for the cubic boron nitride, does not have the characteristics of low friction coefficient, cannot achieve high temperature solid lubrication. Because h-BN belongs to insulation materials, directly through the cathode arc method to form plasma, this study will Ti and h-BN powders were mixed by cold pressing, TiBN composite cathode preparation method of vacuum sintering thermal system research results show that when the content of h-BN within 40wt.%, Ti-BN composite cathode has good conductive properties. With the increasing content of h-BN, Ti-BN composite cathode and the cathode resistance increased significantly, the relative density decreased. The characteristic parameters of Ti-BN composite cathode discharge plasma was measured by plasma mass spectrometer sampling, on the cathode composition, magnetic catheter angle, effect of pressure and current on the plasma distribution. The results show that the Ti-BN composite cathode discharge plasma process 涓昏�佸寘鍚玊i~+,Ti~(2+),BN~+绂诲瓙绛，

本文编号：1656335