Guang Xian

The Structure and Adhesion of Zr/TiAlN Coatings on High-Speed Steel and Cemented Carbide Substrates

Zr/TiAlN coatings as well as single TiAlN coatings were deposited on high-speed steel and cemented carbide substrates by medium frequency magnetron sputtering. The crystal structure and cross-sectional morphology of coatings were evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The adhesion of coatings to substrate was measured by Rockwell indention tests. These investigations show that the main diffraction peak of Zr/TiAlN and TiAlN coatings are corresponding to the TiN phase. The preferred orientation of out TiAlN coatings is obviously affected by Zr interlayer and substrate materials. The TiAlN coatings both on HSS and cemented carbide substrates exhibit a columnar structure. But, the columnar morphology of Zr/TiAlN on cemented carbide substrate becomes ambiguous and this structure of Zr/TiAlN coatings on HSS substrate even changes to isometric. The Rockwell indention results indicate that the adhesion of TiAlN coatings is significantly improved by adding Zr interlayer both on HSS substrate and cemented carbide substrate.

Structure and Properties of TiAlLaN Coatings Deposited at Various Ar/N2 Flow Ratio Using a Mid-Frequency Magnetron Sputtering System

TiAlLaN coatings were deposited on the cemented carbide substrates by mid-frequency magnetron sputtering system. The effects of Ar/N2 flow ratio on the composition, structure, adhesion and hardness followed with elastic modulus and H/E ratio were investigated systematically. Results indicate that all the Ti/Al ratios of the coatings were higher than that of the Ti/Al ratio in the target; however, the Ti/Al ratio increased with the Ar/N2 flow ratio changed. XRD patterns show that the intensity of (111) peak was elevated with the Ar/N2 flow ratio increased. Meanwhile, the peak shifted to lower angles, which implied increases of the lattice parameter. The TiAlLaN coating under the Ar/N2 flow ratio of 3:1 showed the best adhesion, the highest hardness and the lowest H/E ratio which indicated perfect wear resistance.

The Structure and Thermal Properties of ZrAlYN Films Deposited by Magnetron Sputtering

ZrAlYN films were prepared by magnetron sputtering at various N2/Ar flow ratio. The structure, composition and thermal properties were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectrum. The results show that the deposited ZrAlN and ZrAlYN films possessed a single NaCl-type solid solution phase. The ZrAlN film was (200) strongly predominated. The (111) peak was prominently increased in ZrAlYN films and thus the preferred orientation changed to (111) and (200) co-predomination. The crystallinity of ZrAlYN films was gradually degraded with enhanced N2/Ar flow ratio. Both ZrAlN and ZrAlYN films were exhibited a featureless fracture microstructure. The thickness of ZrAlYN films was consistently reduced due to more nitride produced on the surface of targets at higher N2/Ar flow ratio. The ZrAlYN films deposited at 1:5 N2/Ar flow ratio was proved to be the best oxidation resistance under annealing at 1000°C for 2h in air. As N2/Ar flow ratio increased, the oxidation resistance of films was inversely deteriorated due to the decreased yttrium content in films.

The Structure and Mechanical Properties of Me/MeN/TiAlN Trilaminar Coatings Deposited by a Hybrid PVD Coating Technique

The purpose of this study is to investigate the microstructure, mechanical properties and adhesion of Ti/TiN/TiAlN and Zr/ZrN/TiAlN trilaminar coatings, which were deposited on the high-speed steel substrate and cement carbide substrate by a hybrid PVD coating technique. X-ray diffraction technique (XRD) was used to reveal the structure of coatings. The fracture appearance of coatings was presented by scanning electron microscopy (SEM) and the element content was characterized by energy dispersive X-ray (EDX). Hardness and Yongs modulus were measured by using a nanoindentation technique and the adhesion of coatings was carried out with Rockwell HRC indentations. The results showed that all the coatings present a fcc B1 (NaCl type) structure and the TiN (111) is the dominant orientation. The TiAlN coatings with Ti/TiN interlayer presented a typical columnar structure, while the columnar structure became ambiguous in TiAlN coatings with Zr/ZrN interlayer. The chemical composition of TiAlN coatings is almost unacted on the inner interlayer. The hardness of the coatings on CC substrate is greater than that of on HSS substrate. However, the Ti/TiN/TiAlN coatings on HSS substrate has the maximum the H3/E*2 ratio at 0.178 with a lowest hardness. The adhesion of Ti/TiN/TiAlN and Zr/ZrN/TiAlN coatings on CC substrate is remarkable greater than the adhesion of same coatings on HSS substrate.

Effect of Interlayers on the Structure and Properties of TiAlSiN Coatings Deposited on High-Speed Steel Substrate

TiAlSiN coatings with Ti or Cr interlayers were deposited on high-speed steel using magnetron sputtering methods. The structure, crystal morphology and mechanical properties were investigated systematically. The results show that (200) is the dominant preferred orientation in Ti/TiAlSiN coating, while (111) become the predominant orientation of the deposited Cr/TiAlSiN coating, which is related to the surface energy. Due to the changes of the coating growth style, the Cr/TiAlSiN coating shows columnar crystals morphology. The Ti/TiAlSiN coating performs better adhesion and H/E ratio, which is proved to have better wear resistance. But the specimens with Cr interlayer have better hardness and elastic modulus, which is due to the growth style of the crystals.