【作者】 张辉；

【导师】 田修波；

【作者基本信息】 哈尔滨工业大学 ， 材料与化工（专业学位）， 2022， 硕士

【摘要】 管状件在城市地下水管道、石油天然气运输管道、军事器械的身管以及化学介质的传输管道等领域应用广泛。因为工作环境较为严苛,管道的内表面通常受到严重的摩擦磨损和腐蚀作用,容易产生裂纹,影响使用寿命。采用材料表面改性的方法,通过在管状件的内表面沉积一层薄膜可以有效地提高材料的性能,延缓材料的失效。但是管内壁的处理受到管筒尺寸和形状的影响,传统的电镀工艺无法沉积活泼金属并且膜层均匀性差,化学气相沉积需要较高的沉积温度,物理气相沉积可处理材料多并且制备的膜层致密度高、性能优异。本文采用磁控溅射工艺,通过外接脉冲高功率电源,在Cr靶正对基体直喷的模式下研究提高管内沉积Cr膜的均匀性,控制沉积时间60min。溅射过程中工作气压是影响膜层均匀性和性能的重要参数。本文首先研究不同工作气压对于平面基体沉积Cr膜的影响。结果表明:在保持放电功率和脉冲电压一定的情况下,提高工作气压会增强Cr靶的放电作用,靶电流和基体电流均提高,膜层的沉积速率也相应增大。但是提高气压会导致粒子间的相互碰撞加剧,能量损耗增加,平均自由程降低,膜层的致密度降低,表面粗糙度增高,膜层内应力增大。改变工作气压以及低气压下改变管尾辅助阳极电压进行管状基体的放电特性和辉光光谱研究,结果表明:降低工作气压可以减少气体原子的遮挡效应,更多数量的粒子能够运动至管尾位置,提高基体电流的均匀性;管尾辅助阳极对于Ar原子的离化作用明显,电压升高,管中2、管中3和管尾4位置的基体电流趋于一致,同时Cr原子和Cr~+的数量也略有提高。随着工作气压降低,成膜粒子的传输距离增长,管内Cr膜的沉积深度逐渐提高,0.1Pa下管尾位置可以沉积127nm厚的Cr膜。与平面基体的结果相类似,工作气压不会改变Cr膜的择优生长方向,但是气压越高,膜层的表面粗糙度越大、膜基结合强度越差。0.1Pa下晶粒尺寸最小,膜层的硬度最高,耐摩擦磨损性能最好。设置管尾辅助阳极能够改变真空室内的电势分布。电压越高,牵引电子运动的能力越强。辅助阳极电压40V时,膜层的均匀性最好,同时具有最高的薄膜硬度和弹性模量,但是管尾辅助阳极对于Cr的耐摩擦磨损性能提升较小。更多还原

【Abstract】 Tubular parts are widely used in urban underground water pipeline,oil and gas transportation pipeline,military equipment and chemical medium transmission pipeline and other fields.Because of the harsh working environment,the inner surface of the pipeline is usually subjected to serious friction,wear and corrosion,which is easy to crack and affect the service life.By means of surface modification,a thin film deposited on the inner surface of tubular parts can effectively improve the properties of materials and delay the failure of materials.However,the treatment of the inner surface of the tube is affected by the size and shape of the tube.The traditional electroplating process can not deposit active metals and the uniformity of the film is poor.Chemical vapor deposition requires a higher deposition temperature,and the film prepared by physical vapor deposition can deal with many materials and has high density and excellent performance.In this paper,magnetron sputtering technology was used to improve the uniformity of Cr film deposited in tube under the mode of direct injection of Cr target into substrate by external pulse high power supply,the deposition time is controlled for 60min.The working pressure is an important parameter affecting the uniformity and properties of the film during sputtering.In this paper,the effect of different working pressure on Cr film deposition on plane substrate was studied.The results show that when the discharge power and pulse voltage are kept constant,increasing the working pressure can enhance the discharge effect of Cr target,increase the target current and substrate current,and increase the deposition rate of Cr film.However,increasing the pressure will lead to the intensification of particle collision,increase of energy loss,decrease of mean free path and density,increase of surface roughness and the stress in the film.The discharge characteristics and glow spectrum of the tubular matrix were studied by changing the working pressure and the auxiliary anode voltage of the tube tail under low pressure.The results show that the shielding effect of gas atoms can be reduced by decreasing the working pressure,and more particles can move to the position of the tube tail,and the uniformity of the matrix current can be improved.The ionization effect of the auxiliary anode on Ar atom is obvious:with the increase of the voltage,the substrate current of middle 2,middle 3 and end 4 tends to be the same.At the same time,the number of Cr atoms and Cr~+also increased slightly.With the decrease of the working pressure,the transmission distance of the film forming particles increases,and the deposition depth of Cr film in the tube gradually increases.The Cr film with 127nm can be deposited at the end of the tube under0.1Pa.Similar to the results of planar matrix,the working air pressure does not change the preferred growth direction of Cr film,but the higher working pressure can lead to the greater surface roughness and the worse bonding strength of Cr film.Under 0.1Pa,the grain size is the smallest,the hardness of the film is the highest,and the friction and wear resistance is the best.The electric potential distribution in vacuum chamber can be changed by setting auxiliary anode of tube tail.The higher the voltage,the greater the ability to pull electrons around.When the auxiliary anode voltage is 40V,the uniformity of the film is the best.At the same time,it has the highest hardness and elastic modulus,but the additional anode has little improvement on Cr friction and wear resistance.更多还原