Thin Film Metallic Glass Coatings Research Articles

Corrosion resistance and thermal stability of sputtered Fe44Al34Ti7N15 and Al61Ti11N28 thin films for prospective application in oil and gas industry

Fe-and Al-based thin-film metallic glass coatings (Fe44Al34Ti7N15 and Al61Ti11N28) were fabricated using magnetron co-sputtering technique, and their corrosion performances compared against wrought 316L stainless steel. The results of GI-XRD and XPS analyses demonstrated amorphous structure and oxide layer formation on the surface of the fabricated thin films, respectively. The potentiodynamic (PD) polarization test in chloride-thiosulfate (NH4Cl ​+ ​Na2S2O3) solution revealed lower corrosion current (Icorr) (0.42 ​± ​0.02 ​μA/cm2 and 0.086 ​± ​0.001 ​μA/cm2 Vs. 0.76 ​± ​0.05 ​μA/cm2), lower passivation current (Ipass) (1.45 ​± ​0.03 ​μA/cm2 and 1.83 ​± ​0.07 ​μA/cm2 Vs. 1.98 ​± ​0.04 ​μA/cm2), and approximately six-fold higher breakdown potential (Ebd) for Fe- and Al-based coatings than those of wrought 316L stainless steel. Electrochemical Impedance Spectroscopy (EIS) of both films showed 4- and 2-fold higher charge transfer resistance (Rct), 7- and 2.5-times higher film resistance (Rf), lower film capacitance values (Qf) (10 ​± ​2.4 ​μS-sacm-2, and 5.41 ​± ​0.8 ​μS-sacm-2 Vs. 18 ​± ​2.21 ​μS-sacm-2), and lower double-layer capacitance values (Qdl) (31.33 ​± ​4.74 ​μS-sacm-2, and 15.3 ​± ​0.48 ​μS-sacm-2 Vs. 43 ​± ​4.23 ​μS-sacm-2), indicating higher corrosion resistance of the thin films. Cyclic Voltammetry (CV) scan exhibited that the passive films formed on the Fe- and Al-based coatings were more stable and less prone to pitting corrosion than the wrought 316L stainless steel. The surface morphology of both films via SEM endorsed the CV scan results, showing better resistance to pitting corrosion. Furthermore, the thermal analysis via TGA and DSC revealed the excellent thermal stability of the thin films over a wide temperature range typically observed in oil-gas industries.

Preclinical studies of non-stick thin film metallic glass-coated syringe needles

Our objective in this study was to determine the biocompatibility and hemocompatibility of thin film metallic glass (TFMG) and its potential use in hypodermic needles for intramuscular or intravenous injection. Mouse and rabbit models were employed under approval from the Institutional Animal Care and Use Committee (n = 5/group, two groups in total for both animal models). Platelet-rich plasma (PRP) was collected from the whole blood of rabbits (ear vein) without anti-coagulant for use in in vitro coagulation tests. Histological analysis and optical microscopy were used to assess the endothelial structure of the inner lining of veins after being punctured with needles and detained for 3 days. Histological analysis of ear vein sections revealed that the extent of endothelial damage after puncturing with a TFMG-coated needle was 33% less than that produced by bare needles. Our results confirm that the deposition of a thin TFMG layer (e.g., Zr53Cu33Al9Ta5) on the surface of hypodermic needle can have remarkably clinical benefits, including anti-adhesion, reduced invasion, and minimal endothelial damage. Our results also confirm the good biocompatibility and hemocompatibility of the TFMG coatings.

Enhancement of String Tension Using Thin-Film Metallic Glass Coatings

Inspired by the application of metallic glass sheet as face material for improving the performance of golf clubs, the present work was aimed to explore the application of thin-film metallic glass (TFMG) coatings for enhancing the performance of strings. In order to achieve this aim, badminton strings were coated with TFMG coatings of different thicknesses. The compositions of these TFMG coatings were analyzed using an electron probe micro-analyzer. The amorphous structure of the film was verified using X-ray diffraction. In order to simulate the strung tension of the string in the racquet, the coated string was subjected to different pounds of tensile loading and was subsequently impacted by a steel ball to study both energy loss and the coefficient of restitution (COR). It was observed that while the TFMG coatings could reduce the energy loss and increase the COR at impact, they exerted negligible effects on the tensile strength of the string. In addition, there existed an optimum coating thickness, beyond which cracking of the coating would occur, degrading the beneficial effects of the coating.

Beneficial effects of thin film metallic glass coating in reducing adhesion of platelet and cancer cells: Clinical testing

The adhesion of platelet cells is viewed as a first step in thrombus formation, and cancer cell attachment can lead to cancer seeding. In this study, we examined the feasibility of utilizing Zr53Cu33Al9Ta5 thin film metallic glass (TFMG) to minimize the adhesion of human cancer cells (breast cancer cell, colon cancer cell, and esophageal cancer cell), human and animal platelets. TFMG and pure titanium (Ti) were respectively grown on glass substrates to a thickness of 200 nm using magnetron sputtering. TFMG was shown to reduce surface roughness of approximately 27% than Ti coating did on glass samples. The concentrations of all major ions released from the TFMG were well below toxic levels. TFMG surfaces were more effective than Ti in increasing the contact angle of water, phosphate buffer saline (PBS) and blood from different animal species. The application of TFMG to bare surfaces was shown to reduce the attachment area of human platelets by 77% and that of pig platelets by 63%. TFMG also reduced the attachment of cancer cells by up to ~87%. These characteristics can be attributed to a low surface free energy of TFMG-coated surfaces (31.89 mN/m), which is far below that of Ti-coated (39.25 mN/m) and bare glass (47.80 mN/m). These findings demonstrate the considerable potential of TFMG coatings in the fabrication of medical instruments aimed at preventing the adhesion of platelet and cancer cells.

Influence of thin-film metallic glass coating on fatigue behavior of bulk metallic glass: Experiments and finite element modeling

A coating of the Zr-based thin-film metallic glass (TFMG) was deposited on the Zr50Cu30Al10Ni10 bulk metallic glass (BMG) to investigate shear-band evolution under four-point-bend fatigue testing. The fatigue endurance-limit of the TFMG-coated samples is ~ 33% higher than that of the BMG. The results of finite-element modeling (FEM) revealed a delay in the shear-band nucleation and propagation in TFMG-coated samples under applied cyclic-loading. The FEM study of spherical indentation showed that the redistribution of stress by the TFMG coating prevents localized shear-banding in the BMG substrate. The enhanced fatigue characteristics of the BMG substrates can be attributed to the TFMG coatings retarding shear-band initiation at defects on the surface of the BMG.

The development of a Zr-Cu-Al-Ag-N thin film metallic glass coating in pursuit of improved mechanical, corrosion, and antimicrobial property for bio-medical application

The amorphous thin film metallic glass (TFMGs) is a promising material with superior mechanical performance, fatigue properties, corrosion resistance, unique thermal properties, and antimicrobial efficacy. In this study, newly-designed Zr-Cu-Al-Ag-N TFMGs with various nitrogen content were fabricated by adjusting the nitrogen flow rate into the vacuum chamber. The composition of the Zr-Cu-Al-Ag-N thin films were analyzed by field emission electron probe micro-analyzer (FE-EPMA). The amorphous structure of the thin films were examined with grazing angle X-ray diffractometer (GIXRD). The differential scanning calorimetry (DSC) was applied to identify the amorphous characteristics and thermal properties of the thin films. The high resolution transmission electron microscopy (HR-TEM) was used to observe the microstructure and short range order (SRO) structure of the coatings. For a better intrinsic viewpoint, the average interatomic distance was calculated. The calculated distance gets closer with the increasing nitrogen content, which might result from the increase of short range order (SRO) structure. The nano-hardness, elastic modulus were measured with the aid of a nanoindentation tester. A positive relationship between nitrogen content and mechanical properties was acquired. The potentiostat testing and corroded surface observation were executed to quantitatively and qualitatively evaluate the corrosion resistance of the coatings. It is revealed that the corrosion resistance is enhanced as the increasing nitrogen content, which is attributed to the denser-packed structure. To access the antimicrobial performance of the coatings, liquid culture and plate counting method are used under the regulation of Japanese Industrial Standard (JIS Z2801:2000). It is revealed that the antimicrobial rate against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) is over 99.999% for all the TFMG coatings, which is attributed to the ultra-smooth surface roughness and Cu/Ag-containing chemical composition. Finally, the composition of Zr-Cu-Al-Ag-N TFMG with superior mechanical properties, thermal stability, corrosion resistance and antimicrobial efficacy will be revealed and discussed.

Fatigue property improvements of ZK60 magnesium alloy: Effects of thin film metallic glass

The application of thin film metallic glass (TFMG) has been shown to improve the fatigue characteristics of ZK60 magnesium alloys. This paper reports on the deposition of Zr51Cu32Al10Ni7 (Z-TFMG) and W70Ni20B10 (W-TFMG) on ZK60 Mg alloy to a thickness of 200nm and its effect on fatigue characteristics. In four-point-bending fatigue studies at room temperature, the fatigue limits of the bare, W-, and Z-TFMG-coated Mg alloys were 225, 270, and 280MPa, respectively. These values indicate that the TFMG coatings improved fatigue resistance by as much as 24% through 107cycles. The hardness of TFMGs, their excellent adhesion to the substrate, and the resulting reduction in surface roughness are believed to account for the enhanced fatigue characteristics.

Non-stick syringe needles: Beneficial effects of thin film metallic glass coating.

This paper reports on the use of Zr-based (Zr53Cu33Al9Ta5) thin film metallic glass (TFMG) for the coating of syringe needles and compares the results with those obtained using titanium nitride and pure titanium coatings. TFMG coatings were shown to reduce insertion forces by ∼66% and retraction forces by ∼72%, when tested using polyurethane rubber block. The benefits of TFMG-coated needles were also observed when tested using muscle tissue from pigs. In nano-scratch tests, the TFMG coatings achieved a coefficient of friction (COF) of just ∼0.05, which is about one order of magnitude lower than those of other coatings. Finite-element modeling also indicates a significant reduction in injection and retraction forces. The COF can be attributed to the absence of grain boundaries in the TFMG coating as well as a smooth surface morphology and low surface free energy.

Antimicrobial characteristics in Cu-containing Zr-based thin film metallic glass

Zr-based thin film metallic glass (TFMG), exhibiting the unique properties of good glass forming ability (GFA), corrosion resistance, and biocompatibility, can be applied in various novel fields of industries. An ultra-smooth surface is obtained with the TFMG coatings, which is beneficial to modify the work surface. Thus, TFMG can be extended to medical appliances, such as surgical blades and micro-surgery scissors. The aims of this study are to fabricate the Cu-containing Zr-based TFMG onto SUS304 plates and to investigate the surface physical properties and their antimicrobial effects. The chemical compositions of Zr–Cu–Ni–Al coatings are examined by a field emission electron probe micro-analyzer (FE-EPMA). The amorphous structures of all TFMG are characterized by the X-ray diffractometry. The surface properties are analyzed by an atomic force microscope (AFM) and a water contact angle goniometer for the 304 stainless steel substrate and Zr–Cu–Ni–Al TFMG. Liquid culture methods and plate counting methods are used to assess the antimicrobial performance of specimens. The antimicrobial rate against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) under the Japanese Industrial Standard JIS Z2801: 2000 is over 99%. The release of copper ion from TFMG specimen is determined by the inductively coupled plasma-mass spectrometer (ICP-MS) to evaluate the antimicrobial activity of Cu-containing Zr-based TFMG. The results show that the surface of SUS 304 stainless steel substrate can be modified with deposited Zr–Cu–Ni–Al TFMG, and their improved antimicrobial efficacy against those bacteria is attributed to their amorphous rough surface, hydrophobic properties and released copper ion. The TFMG developed in this study with adequate hardness, good adhesion ability and antimicrobial efficiencies can be used as a promising candidate to improve the surface properties of the medical appliances and also to reduce the possibility of nosocomial infection.

Antimicrobial properties of Zr–Cu–Al–Ag thin film metallic glass

Metallic glass as a prominent class of structure and multifunctional materials exhibits several unique properties in mechanical, electrochemical, and thermal properties. This study aimed to realize the advantage of biomedical application and to promote the attainable size of metallic glasses by the physical vapor deposition. The Zr–Cu–Al–Ag thin film metallic glass (TFMG) was deposited on silicon wafer and SUS304 stainless steel substrates by magnetron sputtering with single target. For X-ray diffraction analysis, all TFMGs revealed typical broad peaks around the incident angle of 30 to 50°, suggesting that coatings possess amorphous structure. In addition, diffuse halo ring patterns of transmission electron microscopy indicated a fine amorphorization for TFMG via sputtering process. The variation of surface roughness showed that TFMG derived from higher power of metallic targets revealed rougher morphology. Besides, the roughness of SUS304 stainless steel substrate significantly reduced from 7nm to about 1nm after TFMGs were deposited.The microbes of Candida albicans, Escherichia coli, and Pseudomonas aeruginosa were used and cultivated on the TFMG coatings with medium to investigate the antimicrobial properties. In the incubation experiment, the growth of each microbe was recorded by a digital photography system and the growth area was calculated by image processing software. The growth area of the microbes on the TFMG was mostly smaller than that on SUS304 stainless steel ones within incubation time of 72h, indicating that the TFMGs reveal better antimicrobial capability. Moreover, the coatings exhibit a particularly long-term antimicrobial effect for P. aeruginosa. In summary, the Zr–Cu–Al–Ag prepared by sputtering with a single target device presented superior glass forming ability, and coatings with copper and silver constituents revealed significantly antimicrobial properties. Besides, the surface roughness is another factor to affect the biological activities, suggesting that microbes are difficult to attach and move on an ultra-smooth surface. It is demonstrated in this study that the TFMGs extend attainable size of the metallic glass and show a potential application in medical related field.

Preparation of silicon oxynitride fiber and its mechanical properties

Zr-based thin film metallic glass (TFMG), exhibiting the unique properties of good glass forming ability (GFA), corrosion resistance, and biocompatibility, can be applied in various novel fields of industries. An ultra-smooth surface is obtained with the TFMG coatings, which is beneficial to modify the work surface. Thus, TFMG can be extended to medical appliances, such as surgical blades and micro-surgery scissors. The aims of this study are to fabricate the Cu-containing Zr-based TFMG onto SUS304 plates and to investigate the surface physical properties and their antimicrobial effects. The chemical compositions of Zr–Cu–Ni–Al coatings are examined by a field emission electron probe micro-analyzer (FE-EPMA). The amorphous structures of all TFMG are characterized by the X-ray diffractometry. The surface properties are analyzed by an atomic force microscope (AFM) and a water contact angle goniometer for the 304 stainless steel substrate and Zr–Cu–Ni–Al TFMG. Liquid culture methods and plate counting methods are used to assess the antimicrobial performance of specimens. The antimicrobial rate against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) under the Japanese Industrial Standard JIS Z2801: 2000 is over 99%. The release of copper ion from TFMG specimen is determined by the inductively coupled plasma-mass spectrometer (ICP-MS) to evaluate the antimicrobial activity of Cu-containing Zr-based TFMG. The results show that the surface of SUS 304 stainless steel substrate can be modified with deposited Zr–Cu–Ni–Al TFMG, and their improved antimicrobial efficacy against those bacteria is attributed to their amorphous rough surface, hydrophobic properties and released copper ion. The TFMG developed in this study with adequate hardness, good adhesion ability and antimicrobial efficiencies can be used as a promising candidate to improve the surface properties of the medical appliances and also to reduce the possibility of nosocomial infection.