Tribological Study of Microbearings for MEMS Applications

2005 ◽  
Vol 127 (3) ◽  
pp. 537-547 ◽  
Author(s):  
Daejong Kim ◽  
Dongmei Cao ◽  
Michael D. Bryant ◽  
Wenjin Meng ◽  
Frederick F. Ling
Keyword(s):  
Contact Pressure ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Physical Vapor Deposition ◽  
Wear Test ◽  
Tribological Characteristics ◽  
High Wear Resistance ◽  
X Ray ◽  
Developed Surface

Microsleeve bearings intended for microrotational machinery were fabricated by X-ray lithography and Ni electroplating. Coated to the working surfaces of the bearings was a 900nm thick uniform tungsten hydrocarbon (W–C:H) coating using an inductively coupled plasma (ICP) assisted, hybrid chemical vapor deposition (CVD)/physical vapor deposition (PVD) tool. Tribological characteristics and mechanical properties of as-electrodeposited Ni microbearings, annealed Ni microbearings at 800°C, and W–C:H coated microbearings were investigated. Potential applications of the microbearings may involve very light contact pressure (5-30MPa) and high sliding speed, such as micromotors and microturbines. Conventional pin-on disk test methods on top flat surfaces, (001) planes, cannot effectively predict tribological characteristics because these microbearings use the sidewall (110 plane) as a working surface. A special micro wear tester and friction tester were developed. Surface morphologies of new and worn bearing surfaces were studied using SEM. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) characterized the W–C:H coated microbearings. Test results of the W–C:H coated microbearings (wear characteristics and friction) are also presented. W–C:H coated microbearings had much lower wear rate than uncoated bearings. During the wear test, a transfer layer formed on the counter steel shaft even under very small contact pressure, leading to low steady state friction and high wear resistance.

Tribological Study of Micro Bearings for MEMS Applications

2004 ◽  
Author(s):  
Daejong Kim ◽  
Dongmei Cao ◽  
Michael D. Bryant ◽  
Wenjin Meng
Keyword(s):  
Contact Pressure ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Physical Vapor Deposition ◽  
Wear Test ◽  
Tribological Characteristics ◽  
High Wear Resistance ◽  
X Ray ◽  
Developed Surface

Micro sleeve bearings intended for micro rotational machinery were fabricated by X-ray lithography and Ni electroplating. Coated to the working surfaces of the bearings was a 900nm thick uniform tungsten hydrocarbon (W-C:H) coating using an inductively coupled plasma (ICP) assisted, hybrid chemical vapor deposition (CVD)/physical vapor deposition (PVD) tool. Tribological characteristics and mechanical properties of as-electrodeposited Ni micro bearings, annealed Ni micro bearings at 800°C, and W-C:H coated micro bearings were investigated. Potential applications of the micro bearings may involve very light contact pressure (5∼30MPa) and high sliding speed, such as micro motors and micro turbines. Conventional pin-on disc test methods on top flat surfaces, (001) planes, cannot effectively predict tribological characteristics because these micro bearings use the sidewall (110 plane) as a working surface. A special micro wear tester and friction tester were developed. Surface morphologies of new and worn bearing surfaces were studied using SEM. Raman Spectroscopy and X-ray Photoelectron Spectroscopy (XPS) characterized the W-C:H coated micro bearings. Test results of the W-C:H coated micro bearings (wear characteristics and friction) are also presented. W-C:H coated micro bearings had much lower wear rate than uncoated bearings. During the wear test, a transfer layer formed on the counter steel shaft even under very small contact pressure, leading to low steady state friction and high wear resistance.

Effect of Cu Content on the Tribological Performance of Cr-N Coatings at High Temperatures (840°C)

2009 ◽  
Author(s):  
Kyriaki Polychronopoulou ◽  
Claus Rebholz ◽  
Nicholaos G. Demas ◽  
Andreas A. Polycarpou ◽  
P. N. Gibson
Keyword(s):  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Physical Vapor Deposition ◽  
Tribological Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Content ◽  
Glancing Angle ◽  
Scanning Electron ◽  
Ball On Disc

Cr-N and Cu-Cr-N coatings with Cu content between 3–65 at.%, Cu/Cr ratios in the 0.04–4.5 range and 21–27 at.% N, synthesized by twin e-beam Physical Vapor Deposition (EBPVD) at 450°C, were investigated. Using X-ray photoelectron spectroscopy (XPS), glancing angle X-ray diffraction (GAXRD) and scanning electron microscopy (SEM), in combination with nanoindentation mechanical property measurements and laboratory controlled ball-on-disc sliding experiments, it is shown that Cu-Cr-N coatings with low Cu content (3 at.%) possess sufficient wear resistance for high temperature demanding tribological applications.

COMPOSITION AND NANOHARDNESS OF SiC FILMS DEPOSITED BY ELECTRON BEAM PHYSICAL VAPOR DEPOSITION

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1910-1915 ◽  
Author(s):  
MIN TENG ◽  
XIAODONG HE ◽  
YUE SUN
Keyword(s):  
Electron Beam ◽  
Chemical Bonding ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Physical Vapor Deposition ◽  
Current Intensity ◽  
X Ray ◽  
Deposited Films ◽  
Sic Films

SiC films with a quantity of carbon and silicon were obtained by electron beam physical vapor deposition (EB-PVD) from a sintered SiC target with different current intensity of EB. The X-ray photoelectron spectroscopy (XPS) was used for characterization of chemical bonding states of C and Si elements in SiC films in order to study the influence of current intensity of EB on the compositions in the deposited films. At the same time, the nanohardness of the deposited films was investigated.

5MeV Si Ion Modification on Thermoelectric SiO2/SiO2+Cu Multilayer Films

2011 ◽  
Vol 1354 ◽  
Author(s):  
C. Smith ◽  
S. Budak ◽  
T. Jordan ◽  
J. Chacha ◽  
B. Chhay ◽  
...  
Keyword(s):  
Electron Beam ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Physical Vapor Deposition ◽  
Ion Bombardment ◽  
Multilayer Films ◽  
Binding Energies ◽  
X Ray ◽  
Available Energy ◽  
Energy States

AbstractWe prepared samples by electron beam physical vapor deposition EB-PVD followed by ion bombardment. The samples were than characterized by photoluminescence (PL), x-ray photoelectron spectroscopy (XPS). PL was used to characterize the available energy states. XPS was used to determine the binding energies. The ML’s are comprised of 100 alternating layers of SiO2/SiO2+Cu.

High Quality GaAs Mis Diodes With Very Low Surface State Density

1990 ◽  
Vol 209 ◽  
Author(s):  
Yoshihisa Fujisaki ◽  
Sumiko Sakai ◽  
Saburo Ataka ◽  
Kenji Shibata
Keyword(s):  
Chemical Vapor Deposition ◽  
Density Of States ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
State Density ◽  
High Quality ◽  
Metal Insulator ◽  
X Ray ◽  
Mis Devices

ABSTRACTHigh quality GaAs/SiO2 MIS( Metal Insulator Semiconductor ) diodes were fabricated using (NH4)2S treatment and photo-assisted CVD( Chemical Vapor Deposition ). The density of states at the GaAs and SiO2 interface is the order of 1011 cm-2eV-1 throughout the forbidden energy range, which is smaller by the order of two than that of the MIS devices made by the conventional CVD process. The mechanism attributable to the interface improvement was investigated through XPS( X-ray Photoelectron Spectroscopy ) analyses.

scholarly journals Generation of Charged Ti Nanoparticles and Their Deposition Behavior with a Substrate Bias during RF Magnetron Sputtering

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 443
Author(s):  
Ji-Hye Kwon ◽  
Du-Yun Kim ◽  
Nong-Moon Hwang
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Film Growth ◽  
Film Deposition ◽  
Calculated Density ◽  
X Ray ◽  
Positively Charged ◽  
Made In ◽  
Ti Films

This study is based on the film growth by non-classical crystallization, where charged nanoparticles (NPs) are the building block of film deposition. Extensive studies about the generation of charged NPs and their contribution to film deposition have been made in the chemical vapor deposition (CVD) process. However, only a few studies have been made in the physical vapor deposition (PVD) process. Here, the possibility for Ti films to grow by charged Ti NPs was studied during radio frequency (RF) sputtering using Ti target. After the generation of charged Ti NPs was confirmed, their influence on the film quality was investigated. Charged Ti NPs were captured on amorphous carbon membranes with the electric bias of −70 V, 0 V, +5 V, +15 V and +30 V and examined by transmission electron microscopy (TEM). The number density of the Ti NPs decreased with increasing positive bias, which showed that some of Ti NPs were positively charged and repelled by the positively biased TEM membrane. Ti films were deposited on Si substrates with the bias of −70 V, 0 V and +30 V and analyzed by TEM, field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and X-ray reflectivity (XRR). The film deposited at −70 V had the highest thickness of 180 nm, calculated density of 4.974 g/cm3 and crystallinity, whereas the film deposited at +30 V had the lowest thickness of 92 nm, calculated density of 3.499 g/cm3 and crystallinity. This was attributed to the attraction of positively charged Ti NPs to the substrate at −70 V and to the landing of only small-sized neutral Ti NPs on the substrate at +30 V. These results indicate that the control of charged NPs is necessary to obtain a high quality thin film at room temperature.

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