Plasma diagnosis of tetrahedral amorphous carbon films by filtered cathodic vacuum arc deposition

Filtered cathodic vacuum arc(FCVA)deposition is regarded as an important technique for the synthesis of tetrahedral amorphous carbon(ta-C)films due to its high ionization rate,high deposition rate and effective filtration of macroparticles.Probing the plasma characteristics of arc discharge contributes to understanding the deposition mechanism of ta-C films on a microscopic level.This work focuses on the plasma diagnosis of an FCVA discharge using a Langmuir dualprobe system with a discrete Fourier transform smoothing method.During the ta-C film deposition,the arc current of graphite cathodes and deposition pressure vary from 30 to 90 A and from 0.3 to 0.9 Pa,respectively.The plasma density increases with arc current but decreases with pressure.The carbon plasma density generated by the arc discharge is around the order of10^(10)cm^(-3).The electron temperature varies in the range of 2-3.5 eV.As the number of cathodic arc sources and the current of the focused magnetic coil increase,the plasma density increases.The ratio of the intensity of the D-Raman peak and G-Raman peak(I_(D)/I_(G))of the ta-C films increases with increasing plasma density,resulting in a decrease in film hardness.It is indicated that the mechanical properties of ta-C films depend not only on the ion energy but also on the carbon plasma density.

Optical and electrical properties of BaSnO_(3) and In_2O_(3) mixed transparent conductive films deposited by filtered cathodic vacuum arc technique at room temperature

For the crystalline temperature of BaSnO_(3)(BTO)was above 650℃,the transparent conductive BTO-based films were always deposited above this temperature on epitaxy substrates by pulsed laser deposition or molecular beam epitaxy till now which limited there application in low temperature device process.In the article,the microstructure,optical and electrical of BTO and In_(2)O_(3) mixed transparent conductive BaInSnO_(x)(BITO)film deposited by filtered cathodic vacuum arc technique(FCVA)on glass substrate at room temperature were firstly reported.The BITO film with thickness of 300 nm had mainly In_(2)O_(3) polycrystalline phase,and minor polycrystalline BTO phase with(001),(011),(111),(002),(222)crystal faces which were first deposited at room temperature on amorphous glass.The transmittance was 70%–80%in the visible light region with linear refractive index of 1.94 and extinction coefficient of 0.004 at 550-nm wavelength.The basic optical properties included the real and imaginary parts,high frequency dielectric constants,the absorption coefficient,the Urbach energy,the indirect and direct band gaps,the oscillator and dispersion energies,the static refractive index and dielectric constant,the average oscillator wavelength,oscillator length strength,the linear and the third-order nonlinear optical susceptibilities,and the nonlinear refractive index were all calculated.The film was the n-type conductor with sheet resistance of 704.7Ω/□,resistivity of 0.02Ω⋅cm,mobility of 18.9 cm2/V⋅s,and carrier electron concentration of 1.6×10^(19) cm^(−3) at room temperature.The results suggested that the BITO film deposited by FCVA had potential application in transparent conductive films-based low temperature device process.

STUDY ON DIAMOND LIKE CARBON THIN FILM BY FILTERED VACUUM ARC DEPOSITION

Diamond like carbon thin film is successfully deposited on silicon, titanium and stainless steel substrate at low temperature in a filtered vacuum arc deposition system. Arc discharges are established on a graphite cathode in the system with a toroidal macroparticle filter. A cathode activating magnetic field and a filtered magnetic field to collimate the plasma beam are applied. Ion current convected by the plasma beam is measured with a negatively biased probe. It is shown that the magnetic field of the coils located on the plasma duct has a strong influence on cathode spot behavior. Orthogonally the designed experiments are carried out to optimize the deposition parameters of arc stability. Finally, the diamond like carbon thin films are studied by scanning electron microscope (SEM) and Raman spectrum.

Experimental Research of DLC Film Deposited by Filtered Vacuum Arc Evaporation

Diamond like carbon (DLC) films was grown successfully on silicon, titanium and high speed steel (HSS) substrate at low temperature in a filtered vacuum arc deposition system. Arc discharges were established on a graphite cathode in this home built system with a toridal macroparticles filter. Ion current convected by the plasma beam was measured with a negatively biased probe. It was shown that the magnetic field of the coils located on the plasma duct has a strong influence on ion current. Scanning electron microscope (SEM), atomic force microscope (AFM) and Raman spectrum are used to study the DLC films. Tribological behaviors of the deposited film are also studied.

Research and practice on the vacuum filter in emulsion system for tandem cold strip mill

This paper introduces working principle and technical features of vacuum filter in emulsion system for tandem cold strip mill.Based on specific cases,this paper analyses and assesses the effect before and after using the emulsion system with the usage of the vacuum filter for strip mill.Compare with the effect when using the first generation vacuum filter,the emulsion quality is improved significantly by using the second generation vacuum filter,which at the same time ensures steady operation of the rolling mill and surface quality of the mill products. As a result,investment and running costs are lowered,emissions of the waste emulsion are reduced,waste water treatment costs are reduced and so as the environmental pollution.It can be seen the second generation vacuum filter has obvious economic and environmental benefits.Therefor,it suggests that the filter should be used widely in the field of automotive,environmental protection rolling steel and nonferrous metals.

Effect of bias voltage on microstructure,mechanical and tribological properties of TiAlN coatings

TiAlN multilayer coatings composed of TiAl and TiAlN layers were deposited on ZL109 alloys using filtered cathodic vacuum arc(FCVA)technology.The effect of bias voltage on the microstructure and properties of the coating was systematically studied.The results show that the coating exhibits a multi-phase structure dominated by TiAlN phase.As the bias voltage increases,the orientation of TiAlN changes from(200)plane to(111)plane due to the increase of atomic mobility and lattice distortion.The hardness,elastic modulus and adhesion of the coating show the same trend of change,that is,first increase and then decrease.When the bias voltage is 75 V,the coating exhibits the highest hardness(~30.3 GPa),elastic modulus(~229.1 GPa),adhesion(HF 2)and the lowest wear rate(~4.44×10^(−5)mm^(3)/(N·m)).Compared with bare ZL109 alloy,the mechanical and tribological properties of TiAlN coated alloy surface can effectively be improved.

ENHANCING ADHESION OF TETRAHEDRAL AMORPHOUS CARBON FILMS

Objective The high energy ion bombardment technique is applied to enhancing the adhesion of the tetrahedral amorphous carbon (TAC) films deposited by the filtered cathode vacuum arc (FCVA). Methods The abrasion method, scratch method, heating and shaking method as well as boiling salt solution method is used to test the adhesion of the TAC films on various material substrates. Results The test results show that the adhesion is increased as the ion bombardment energy increases. However, if the bombardment energy were over the corresponding optimum value, the adhesion would be enhanced very slowly for the harder material substrates and drops quickly, for the softer ones. Conclusion The optimum values of the ion bombardment energy are larger for the harder materials than that for the softer ones.

Tribological properties of multilayer tetrahedral amorphous carbon coatings deposited by filtered cathodic vacuum arc deposition

Tetrahedral amorphous carbon(ta‐C)has emerged as an excellent coating material for improving the reliability of application components under high normal loads.Herein,we present the results of our investigations regarding the mechanical and tribological properties of a 2‐μm‐thick multilayer ta‐C coating on high‐speed steel substrates.Multilayers composed of alternating soft and hard layers are fabricated using filtered a cathodic vacuum arc with alternating substrate bias voltages(0 and 100 V or 0 and 150 V).The thickness ratio is discovered to be 1:3 for the sp2‐rich and sp3‐rich layers.The results show that the hardness and elastic modulus of the multilayer ta‐C coatings increase with the sp3 content of the hard layer.The hardness reached approximately 37 GPa,whereas an improved toughness and a higher adhesion strength(>29 N)are obtained.The friction performance(μ=0.07)of the multilayer coating is similar to that of the single layer ta‐C thick coating,but the wear rate(0.13×10^(–6) mm^(3)/(N∙m))improved under a high load of 30 N.We further demonstrate the importance of the multilayer structure in suppressing crack propagation and increasing the resistance to plastic deformation(H3/E2)ratio.