Dissertation > Industrial Technology > Metallurgy and Metal Craft > Metallurgy and Heat Treatment > Metal corrosion protection,metal surface treatment > Corrosion control and protection > Metal surface protection technology

MoS_2-Ti and CrTiAlN MoS_2-Ti composite coating microstructure and properties of

Author XuZuo
Tutor JiangJiang
School Shandong University
Course Materials Science
Keywords Magnetron sputter ion plating CrTiAlN MoS2-Ti CrTiAlN MoS2-Ti Thermal stability
CLC TG174.4
Type Master's thesis
Year 2008
Downloads 124
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Closed field unbalanced magnetron sputter ion plating process temperature is low, the workpiece is not easy deformation, simple process, you can control the coating composition and structure, while the technology also combines the advantages of the combination of strong ion plating, the structure can be prepared appropriate performance of the new gradient coating, in order to meet the complex conditions of service tool coating. Closed field unbalanced magnetron sputter ion plating technique can be used as the final treatment process for high-speed steel cutting tools of the coating. In this paper, closed field unbalanced magnetron sputter ion plating technology in the domestic W 6 Mo 5 Cr 4 V 2 High-speed steel substrate prepared CrTiAIN, MoS 2 -Ti, CrTiAlN MoS 2 -Ti coating. By introducing the intermediate layer method to improve the coating and the substrate bonding strength. Utilization of optical microscopy, electron probe microanalysis (EPMA), X-ray diffraction (XRD), transmission electron microscopy (TEM), differential thermal analysis (DTA) and other technical means of the composite coating surface morphology, composition distribution, Microstructure and thermal stability were characterized and studied. The results showed that, CrTiAlN coating is composed of nanocrystalline grain size of about 10 ~ 30nm. CrTiAlN microhardness about 2450HV0.025. CrTiAlN phase composition of the coating is face-centered cubic structure (Cr, Ti, Al) N solid solution phase, solid solution of (111) crystal face has a strong preferential growth trend. Titanium, aluminum, chromium and nitrogen in the sputtering, the formation of TiN, AlN and CrN having the same lattice structure, similar to the lattice constant, coherent interfaces can be formed, the coating and the substrate to improve the bonding strength. Rendering chromium and titanium, aluminum, the coating composition of the top tapered to provide sufficient strength and hardness combined with the support and nitrogen not in contact with the substrate, the coating to avoid embrittlement. Titanium atom and aluminum atom in the solid solution crystal lattice distortion, resulting in substitution solid solution strengthening, the coating has high hardness. Chromium and aluminum in the coating surface to form Al 2 O 3 , Cr 2 O 3 protective film can to prevent further oxidation of the coating, improved thermal stability of the coating. MoS 2 -Ti coating is composed of nanocrystalline and amorphous. The hardness of the coating 980HV0.025. X-ray diffraction found easily slip plane (002) dominates, the coating has a low coefficient of friction. MoS 2 -Ti oxide coating temperature of about 503.8 ℃, much higher than the pure MoS 2 of 315 ℃. Can be reduced by adding titanium MoS 2 -Ti composite coating the oxygen impurity content, reducing the voids and pores in the coating to improve the compactness of the coating, titanium can also play a solid solution strengthening , and improve the strength of the coating hardness. Titanium is oxidized to form the oxide protective film, the coating can delay the rate of oxidation of Mo, improve the thermal stability of the coating. CrTiAlN MoS 2 -Ti coating is a nano-crystalline and amorphous components. CrTiAlN MoS 2 -Ti coating hardness 1150HV0.025. CrTiAlN MoS 2 -Ti oxide coating temperature of about 507.3 ℃. CrTiAlN high hardness layer having the protective effect of the skeleton, to delay caused by the plastic deformation of MoS 2 -Ti coating premature tearing and peeling, to improve the strength and hardness of the composite coating; MoS 2 -Ti coating may play a self-lubricating effect, reducing the friction coefficient of the coating; multilayer structure interface effect, can improve the coating hardness, toughness and resistance to crack the coating to improve the capacity for expansion; the presence of amorphous phase in the coating, but also help improve the coating toughness.

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