Magnesium alloy coatings by magnetron sputtering deposition of Cr-based study of the structure and characteristics

Title: Magnesium alloy coatings by magnetron sputtering deposition of Cr-based study of the structure and characteristicsAuthor: Dan YongjingDegree-granting units: Chongqing UniversityKeywords: magnetron sputtering;; CrN_x coating;; CrN_xO_yC_z coating;; CrTiAlN coating;; friction and wearAbstract:
Mg alloy is the most promising future of Neodymium Magnets structural materials, but the surface quality is soft and corrosive important issues to be resolved. Although
However, current applications of Mg alloys on surface treatment technology to improve the performance of the Mg alloy surface, but the combination of performance prepared coating, friction
Rub wear and mechanical properties of Mg alloys can not meet all the key components in the field of application. Magnetron sputtering is the main surface of the PVD
Processing technologies, preparation of the coating has a strong combination of performance and the advantages of high density; low deposition temperature required to meet the Mg alloy
Low process temperature requirements. Therefore, the magnetron sputtering deposition of hard coatings to improve friction and wear of Mg alloy surface provides a thought
Road.
In the current study, using planar magnetron sputtering deposition on the Mg alloy coating and CrNxOyCz CrNx coating, and
By scanning electron microscopy (SEM), photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis techniques such as structural properties of the coating was
Characterization. Closed magnetic field using unbalanced magnetron sputter ion plating deposition CrTiAlN coating by transmission electron microscopy (TEM), microhardness
Instrument and experimental study of friction and wear on the coating of Mg interface structure, mechanical properties and tribological performance. It also discusses the column
Shaped crystal growth and the evolution of surface profile characteristics. The major findings are as follows:
① CrNx depends on the structural characteristics of the coating deposition
Process, including substrate temperature, N2 concentration, target current density and substrate bias. Deposition rate is a function of current density of secondary growth
Relationship, leading to increased deposition rate of the N2 content of exponential decay. Of Mg alloy coated with N2 CrNx on increasing the concentration of the trend
To more open borders in the form.
② CrN coating involves the deposition of Cr bridging layer, CrNx transition layer and chemical ratio
CrN layer. Cr film on the magnesium http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets alloy columnar growth originated in the mesh film, CrN coating columnar growth mechanisms, including shelter and annexation. Plane
The average diameter and particle size and thickness of the variance σ2 are linear, surface roughness and thickness exponential relationship.

③ substrate surface profile evolution depends on the coating surface coating thickness, surface profile with the coating thickness tends to smooth. As the phase
Within the coarse surface roughness increased with the coating thickness, while the increase in bias power will lead to reduced surface profile deviation.
CrNx coating surface roughness and a linear relationship between the concentration of N atoms, and the thickness of the exponential relationship.
④ CrNxOyCz coating columnar Health
Long, the coating contains CrN, Cr2N, Cr3C2, Cr2O3, CrO2 and CrNxOy phase; contamination or oxidation of the concentration of O and C atoms on the surface
Subject to the depth distribution of first-order exponential decay, in the coating is non-Cr2N Cr3C2 and stable phase. Friction and wear characteristics than the coating
CrNx coating worse.
⑤ AZ31-Mg alloy wear rate of standard SWR to 1055 × 10-15m3 · N-1 · m-1, and in the Mg
Alloy coating on CrTiAlN SWR only 2.4 × 10-15m3 · N-1 · m-1. -50V when the bias in the binding force of the coating CrTiAlN
To 10N.
⑥ When the level in N2 and the substrate bias of-55V, when, CrTiAlN coating and WC-Co6% friction between the ball mill
Minimum loss, the friction coefficient can be stable at 0.2-0.3. CrTiAlN/MoS2 coating friction and wear performance than CrTiAlN coating significantly improved,
Sliding friction cycles Nc 70,000 times, the friction coefficient can be stabilized at between 0.2-0.35.Degree Year: 2009