Abstract
TiN films have high hardness, low wear coefficient, and other good properties. However, in modern industry, traditional TiN films cannot meet the more stringent requirements on hardness and higher temperature. Many methods have been attempted to improve the properties of TiN films including incorporating other elements such as Al, Si, C, B, etc. Since Veprek first reported the Ti-Si-N nanocomposite film prepared by CVD with the hardness exceeding 70GPa, this kind of Ti-Si-N film has become very attractive due to its high hardness, wear resistance, good thermal and chemical stability. Ti-Si-N films are known to have a microstructure characterized by nanocomposite of nc-TiN/a-Si3N4, i.e. nano-sized TiN crystallites embedded in an amorphous silicon nitride matrix. The presence of nanometer scale grains can hinder the generation and movement of dislocations, stop crack propagation due to the presence of grain boundaries, and suppress grain-boundary sliding. The end result is improved hardness.
Ti-Si-N films are usually synthesized by plasma-enhanced chemical vapor deposition (PECVD) or by reactive magnetron sputtering. The influence of the deposition conditions including the bias voltage, N2 partial press, substrate temperature has been reported. However, previous reports do not fully explain the effects of Si addition to TiN on the bonding structure, microstructure, and roughening kinetics of the nanocomposite Ti-Si-N thin films. Moreover, knowledge of the interaction between the embedded nanocrystalline TiN and the amorphous Si3N4 matrix is very limited. Furthermore, the adhesive strength between the film and substrate has seldom been investigated. In this work, hard nanocomposite Ti-Si-N films are deposited on 321 stainless steel substrates by direct current (DC) reactive magnetron sputtering using a Ti-Si mosaic target consisting of a Ti plate and Si chips. During deposition, the bias voltages range fiom -50V to -150V. The composition, microstructure and mechanical properties (hardness, Young's module and adhesive strength) are investigated using EDS, XRD, XPS, AFM, nano-indentation and scratch tests. The results indicate that the hardness of Ti-Si-N gradually rises with the increasing Si contents in the layer until the peak value of 42GPa appears corresponding to the Si content of lOat%. The hardness then decreases with further increasing of the Si content. XRD, XPS, and AFM reveal that the hardest Ti-Si-N film consists of fine TiN crystallites (approximately 5nm in size) surrounded by amorphous Si3N4. The preferential growth of TiN is indicated in the XRD patterns. Shifts from a strong (111) orientation in pure TiN film to a weak (200) orientation with Si addition are seen. All the Ti-Si-N films show high adhesive strength indicated by the scratch tests. The strengthening mechanism of such nanocomposite films is also investigated.
Ti-Si-N films are usually synthesized by plasma-enhanced chemical vapor deposition (PECVD) or by reactive magnetron sputtering. The influence of the deposition conditions including the bias voltage, N2 partial press, substrate temperature has been reported. However, previous reports do not fully explain the effects of Si addition to TiN on the bonding structure, microstructure, and roughening kinetics of the nanocomposite Ti-Si-N thin films. Moreover, knowledge of the interaction between the embedded nanocrystalline TiN and the amorphous Si3N4 matrix is very limited. Furthermore, the adhesive strength between the film and substrate has seldom been investigated. In this work, hard nanocomposite Ti-Si-N films are deposited on 321 stainless steel substrates by direct current (DC) reactive magnetron sputtering using a Ti-Si mosaic target consisting of a Ti plate and Si chips. During deposition, the bias voltages range fiom -50V to -150V. The composition, microstructure and mechanical properties (hardness, Young's module and adhesive strength) are investigated using EDS, XRD, XPS, AFM, nano-indentation and scratch tests. The results indicate that the hardness of Ti-Si-N gradually rises with the increasing Si contents in the layer until the peak value of 42GPa appears corresponding to the Si content of lOat%. The hardness then decreases with further increasing of the Si content. XRD, XPS, and AFM reveal that the hardest Ti-Si-N film consists of fine TiN crystallites (approximately 5nm in size) surrounded by amorphous Si3N4. The preferential growth of TiN is indicated in the XRD patterns. Shifts from a strong (111) orientation in pure TiN film to a weak (200) orientation with Si addition are seen. All the Ti-Si-N films show high adhesive strength indicated by the scratch tests. The strengthening mechanism of such nanocomposite films is also investigated.
| Original language | English |
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| Publication status | Published - Sept 2005 |
| Event | The 8th International Workshop on Plasma-based Ion Implantation and Deposition - Southwest Jiaotong University, Chengdu, China Duration: 18 Sept 2005 → 22 Sept 2005 |
Conference
| Conference | The 8th International Workshop on Plasma-based Ion Implantation and Deposition |
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| Place | China |
| City | Chengdu |
| Period | 18/09/05 → 22/09/05 |