Microstructure-driven strengthening of TiB2 coatings deposited by pulsed magnetron sputtering
Microstructure-driven strengthening of TiB2 coatings deposited by pulsed magnetron sputtering
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DOI：
10.1016/j.surfcoat.2019.04.042
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发表时间：
2019-06
影响因子：
5.4
通讯作者：
M. Polyakov;M. Morstein;X. Maeder;T. Nelis;D. Lundin;J. Wehrs;J. Best;T. Edwards;M. Döbeli;J. Michler
中科院分区：
文献类型：
--
作者：
M. Polyakov;M. Morstein;X. Maeder;T. Nelis;D. Lundin;J. Wehrs;J. Best;T. Edwards;M. Döbeli;J. Michler
二硼化钛(TiB2)是一种具有六方晶体结构的硬质涂层，即使与铝及其合金接触，也能在高温下保持高硬度和惰性。因此，二硼化钛涂层经常用于切割、成型、注射成型和摩擦学应用。虽然这种涂层有多种沉积路线可用，但在涂层微观结构和内部应力的控制方面存在限制，这就导致了工业应用中薄膜性能和薄膜完整性的限制。高功率脉冲磁控溅射(HiPIMS)是一种沉积技术，由于其固有的微结构控制能力，近年来在沉积二硼化钛薄膜方面显示出良好的前景。然而，对于这项技术来说，诸如相对较低的沉积速率和较高的压应力等问题还没有得到充分的解决。以陶瓷TiB2为靶材，在圆柱形旋转磁控管上实现了一种基于HIPIMS的TiB2新工艺和高平均功率工艺优化。通过调节HiPIMS的脉冲条件，在高沉积速率下获得了高硬度的薄膜，同时通过光学发射光谱和朗缪尔探针测量保持了高的电离速率。利用微柱压缩和纳米压痕技术研究了薄膜的变形行为。室温下的测试表明，在其他相同的条件下，与传统的直流磁控溅射沉积的薄膜相比，新的HiPIMS涂层具有更高的断裂强度。用透射电子显微镜的微观结构研究解释了变形差异的原因。
Titanium diboride (TiB2) is a hard coating with a hexagonal crystal structure that maintains its high hardness and inertness at elevated temperatures, even in contact with aluminum and its alloys. Therefore, titanium diboride coatings are often used in cutting, forming, injection molding and tribological applications. While there are multiple deposition routes available for this coating, there are limitations in terms of control of the coating microstructure and internal stresses, which translate to limitations in the film properties and film integrity in industrial use. High-power impulse magnetron sputtering (HiPIMS) is a deposition technique which has recently shown promise for depositing titanium diboride films due to its intrinsic microstructural control capabilities. However, issues such as relatively low deposition rates and high compressive stresses have not been sufficiently addressed for this technique. This investigation reports on the implementation of a new HiPIMS-based TiB2process and a high average-power process optimization from a cylindrical rotating magnetron fitted with ceramic TiB2as the target material. By tuning the HiPIMS pulse conditions, high-hardness films were obtained at high deposition rates, while maintaining high ionization rates as determined by optical emission spectroscopy and Langmuir probe measurements. Micropillar compression and nanoindentation techniques were used to investigate the film deformation behavior. Tests at room temperature showed superior fracture strengths for the new HiPIMS coatings as compared to films deposited by traditional direct current magnetron sputtering under otherwise identical conditions. The differences in deformation are explained by a microstructural investigation by transmission electron microscopy.