Micromechanical Probe Research Articles

Erosion-corrosion behaviour of high manganese steel used in slurry pipelines

The regular replacement and maintenance of steel pipes used to transport slurry in oil sands mining and extraction continue to represent a major expense for oil sands operations. Pipeline steels such as API 5 L X65 and X70 are the main materials for the slurry transport system. In our previous work, dual-phase stainless steel showed excellent performance in aeriated (high dissolved oxygen) slurries operated at low to moderate velocities involving erosion-corrosion. However, the benefits of using stainless steel diminish as the oxygen in slurry is depleted or at higher slurry velocities at which mechanical properties, particularly deformation energy or strain-hardening capability, of the steel become more dominant. This article reports our recent studies on erosion-corrosion of high manganese steel at different slurry velocities (3.5 m/s and 5.5 m/s) and different dissolved oxygen levels (0.6 ppm and 3.8 ppm). The erosion-corrosion tests were performed at 60 °C in sand-containing slurry (20% vol. silica) with 500 ppm chloride, which simulated common field situation. Characterization of the steel was carried out with optical and scanning electron microscopy, energy dispersive x-ray spectrometry, x-ray diffraction technique, micro-mechanical probe, and electrochemical testing. The performance of the high manganese steel was compared to those of API 5 L pipeline steels commonly used in slurry transport, ASTM A1053 Gr.50 dual-phase ferritic-martensitic stainless steel, and AR400 martensitic hard plate. Results of this investigation demonstrate how the high strain-hardening capability of the high manganese steel produces an outstanding erosion resistance, which is more than two times as high as those of ferritic steels. The results are compared to those obtained through field trials performed in an oil sands coarse tailings pipeline.

Erosion-corrosion behaviour of steels used in slurry pipelines

The regular replacement and maintenance of steel pipes used to transport the slurry processed in oil sands mining and extraction represent a major expense for oil sands operations. Erosion-corrosion tests reveal that the performance of the steels is strongly influenced by the slurry velocity, which affects the severity of the erosion-corrosion synergy. In this study, the erosion-corrosion behavior of API 5L X65, X70, and X80 steels was assessed at two different slurry velocities (3.5 and 5 m/s) and two different aeration levels or dissolved oxygen (DO) levels (0.6 and 3.8 ppm). Results of the tests were compared to those of an ASTM A1053 Gr.50 dual-phase (DP) stainless steel and AR400 hard plate. The tests were performed at 60 °C in sand-containing slurry (20% vol. silica) with 500 ppm chloride, which replicated common field conditions. Characterization of the steels was carried out with optical and scanning electron microscopy, energy dispersive x-ray spectrometry, x-ray diffraction technique, micro-mechanical probe, and electrochemical testing. The results showed that at the DO level of 3.8 ppm, the DP stainless steel featured the highest erosion-corrosion resistance at the slurry velocity of 3.5 m/s, while its performance was inferior to that of the carbon steels as the slurry velocity was increased to 5.5 m/s. At the lower DO level, the DP stainless steel erosion resistance was relatively similar to the carbon steels but deteriorated as slurry velocity was increased. Possible mechanisms responsible for the observed variations in the erosion-corrosion resistance under the testing conditions are analyzed and discussed.

Incorporating TiO2 nanotubes with a peptide of D-amino K122-4 (D) for enhanced mechanical and photocatalytic properties.

Titanium dioxide (TiO2) nanotubes are promising for a wide variety of potential applications in energy, biomedical and environmental sectors. However, their low mechanical strength and wide band gap limit their widespread technological use. This article reports our recent efforts to increase the mechanical strength of TiO2 nanotubes with lowered band gap by immobilizing a peptide of D-amino K122-4 (D) onto the nanotubes. Topographies and chemical compositions of the peptide-coated and uncoated TiO2 nanotubular arrays were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy (XPS). Properties of the peptide-coated and uncoated TiO2 nanotubular arrays, including hardness, elastic modulus, electron work function and photocurrent, were evaluated using micromechanical probe, Kelvin Probe and electrochemical system. Effect of the peptide on surface conductivity was also investigated through current mapping and I–V curve analysis with conductive atomic force microscopy. It is demonstrated that the peptide coating simultaneously enhances the mechanical strength, photocatalytic and electrical properties of TiO2 nanotubes.

Design principle of micro-mechanical probe for lateral-deflection-controlled friction force microscopy

Design principles of lateral-deflection-controlled friction force microscopy (FFM) are presented. Lateral-deflection-controlled FFM can overcome a fundamental problem of dual-axis FFM and can provide higher lateral resolution by compensating for friction force and providing effectively high rigidity to the probe. In this paper, key micro components are investigated: micro structures for detection of lateral probe deflection and for lateral drive of the probe. The micro structure for deflection detection is fabricated at the end of the probe and is used in combination with an optical lever method. The micro structure that reflects light (positive type) can provide higher sensitivity than a conventional structure that does not reflect light (negative type). For the probe lateral drive, a micro conduction structure that connects the probe with a support beam is used. A micro electrical conduction structure using stiction is introduced, and its feasibility is experimentally confirmed. These micro structures can improve the measurement accuracy.

The State of Art Survey on Micro cantilevers for MEMS Devices

Arrival of Micro-electromechanical system (MEMS) in the last decade has been immense and ever growing. MEMS is an expanding and fast growing technology with an extensive range of applications. Micro cantilevers belongs to MEMS set of devices and are often used for detection of forces in Micromechanical Sensors(e.g. pressure sensors & accelerometers) and probe for force sensor to atomic force microscope used as transducers, transport mechanisms, relays, switches, resonators etc. In this paper, the relative study and recent development of different micro cantilevers which differ in the material being used and in their construction are discussed and compared to each other based on various parameters.

Design principle of micromechanical probe with an electrostatic actuator for friction force microscopy

It is important to understand friction force in micro/nano mechanical devices both at high sliding speed and with high lateral resolution. Dual-axis friction force microscopes that can provide high lateral resolution and accuracy have been proposed; however, the sliding speed is limited by the probe scan speed. While a micro mechanical probe (MMP) with an electrostatic actuator can overcome this problem, details of probe design have not been established yet. This paper presents the principle of the mechanical design for an MMP with high force sensitivity and sufficient drive force. The dimensions of the double cantilever beam control the spring constants, resonant frequencies, and drive force. The use of an actuated MMP enables accurate friction force microscopy at high sliding speeds, which is required for the design of micro/nano mechanical devices.

Measured Viscous and Dry Friction Forces in Nanometer-Thick Lubricant Film by Friction Force Microscopy with Micromechanical Probe

A new method for measuring the contribution of the local viscous and dry friction forces on the micrometer scale is described. The velocity dependence of the local friction force is obtained using a dual-axis micromechanical probe with an electrostatic actuator. It is used to obtain the local damping coefficient and dry friction force of nm-thick lubricant films patterned on the micrometer scale. This method is useful for clarifying the mechanism of thin-film-based and boundary lubrications.

J164012 二軸独立型摩擦カプローブによる局所的な振動減衰メカニズムの解明

Properties of chemically textured surfaces on the small scale are difficult to measure. Measurement of local friction can provide properties of textured surfaces. Friction force microscope (FFM) is widely used for measurement of local friction properties. A recently developed actuated dual-axis probe, called micro mechanical probe (MMP), can provide friction force measurement at wider range of sliding speeds. In this paper, the actuated probe was applied to quantification of friction damping mechanism of chemically textured surfaces on the micro scale by measuring the sliding-speed-dependence of friction force, which can provide properties of chemically textured surfaces.

An electrostatic actuator for dual-axis micro-mechanical probe on friction force microscope

A dual-axis friction force microscope (FFM) probe with an electrostatic actuator has been developed. This actuator can modulate the sliding speed of the probe. A micro-drive part and the probe part were separately fabricated by anisotropic chemical etching and then combined using micro concave–convex alignment structures. This resulted in 10-μm-order gaps between electrodes of the probe and drive parts and could provide a sufficient electrostatic force. The laterally vibrated probe demonstrated the evaluation of the local rheological properties of the 1.9-nm-thick liquid lubricant film patterned in a 10-μm wide line and space pattern. A dual-axis micro-mechanical probe with this electrostatic actuator can be used to clarify local tribological and rheological properties.

D-1-1 静電アクチュエータ付き二軸独立型摩擦力顕微鏡用プローブの開発(D-1 マイクロアクチュエータ,口頭発表:マイクロナノメカトロニクス)

It is important to increase the sliding speed in friction force microscopy (FFM). Although dual-axis probes for FFM can provide the accurate quantification of the tribological properties, it is difficult to increase the sliding speed. In this paper, using micromachining techniques, a dual-axis probe with an electrostatic actuator is presented. This dual axis probe, called micromechanical probe, consists of double cantilever and torsion beams for the detection of lateral and normal forces, respectively. The micro-drive part fabricated by anisotropic chemical etching were combined with the probe. The fine alignment was achieved by fabricating micro convex and concave structures on the microelectrode and probe parts, respectively. The micromechanical probe with an electrostatic actuator can provide the accurate quantification of the tribological properties under high speed sliding conditions.

Application of aluminide coatings modified with yttrium for protecting corn post-harvest processing equipments against erosion in food industries

Recent studies demonstrate that aluminide coatings are beneficial to wear and erosion resistance and also oxygenactive elements such as yttrium can remarkably improve this resistance. In this research, the micro-hardness of the aluminide coatings with and without yttrium on carbon steel AISI 1045 was investigated using a micro-mechanical probe in post-harvest processing equipments in food industries. Wear of the samples was measured using a pin-on-disk tribometer. The erosion loss of specimens against five varieties of corn was also evaluated using a slurry erosion test machine. Experimental data were analyzed statistically using a 5-factor completely randomized design to study the effect of corn varieties, moisture content at three levels (13, 15, and 17% (wet basis)), and rotation velocity of the slurry erosion machine at three levels (150, 300, and 450 rpm) on erosion resistance. The results showed that the aluminide coatings improved the wear and erosion resistance of substrate carbon steel AISI 1045; yttrium markedly improved the hardness of the aluminide coating and its wear and erosion resistance. The erosion loss of materials was significantly (P < 0.01) influenced by the variety of corn, moisture content and rotation velocity. Both aluminide coating without yttrium and aluminide coating with yttrium showed higher wear and erosion resistance than carbon steel AISI 1045 substrate.

Quantification of Friction Force on Dual-Axis Micro-Mechanical Probe for Friction Force Microscopy

Quantification of Friction Force on Dual-Axis Micro-Mechanical Probe for Friction Force Microscopy

A-11 摩擦力顕微鏡用二軸独立型プローブの摩擦力・鉛直力の検出におけるクロストーク効果(口頭発表:ヘッド・ディスク・インターフェイス)

Conventional friction force microscopes (FFMs) had the disadvantage of low force sensitivity due to mechanical interference between torsion caused by friction force and deflection by normal force. To overcome this disadvantage, we developed a dual-axis micro-mechanical probe that measures the lateral force with a double cantilever and the vertical force with a torsion beams. We investigated force sensitivities by FFM measurements and mechanical interference by finite element method. It is clarified that the dual-axis probe has high force sensitivity and low crosstalk effect.

MNM-P6-6 摩擦力顕微鏡用二軸独立検出型マイクロ・メカニカルプローブの高精度化(P6 情報・精密機器におけるマイクロ・ナノテクノロジー)

Conventional friction force microscopes (FFM) had the disadvantage of low force sensitivity due to mechanical interference between torsion caused by friction force and caused deflection by normal force. We have developed dual-axis micro-mechanical probe. It measures the lateral force by detecting the deflection of the double cantilever and measures the vertical force by the torsion beam. To quantify the friction force, it is import to improve the detection sensitivity of the lateral displacement and calibrate the displacement accurately. In this study, we present methods for improvement of displacement sensitivity and accurate calibration.

Fabrication, Geometry, and Mechanical Properties of Highly Ordered TiO2 Nanotubular Arrays

Highly ordered TiO2 nanotubular arrays have attracted increasing interest because of their exceptional physical properties and wide range of existing and potential applications. Techniques for fabrication and characterization of TiO2 nanotubular arrays have been reported extensively; however, the mechanical behavior of TiO2 nanotubular arrays has not been systematically investigated, which could be critical for their applications. In this study, we synthesized a series of highly ordered TiO2 nanotubular array films from a few to hundreds of microns in thickness by changing the anodic voltage or reaction time during anodization. The as-prepared nanotubular arrays were examined carefully using field emission scanning electron microscopy, and their mechanical properties were evaluated using a micromechanical probe and a microtribometer. It was demonstrated that the diameter and wall thickness of TiO2 nanotubes were almost independent of the anodic voltage and anodization time, whereas thicker nanotubular array films or longer nanotubes could be fabricated at higher voltage or with longer anodization time. The micromechanical probing tests demonstrated that the apparent Young’s modulus, η value, and hardness decreased as the thickness of the nanotubular array films increased due to the densification and collapse of longer nanotubes under external force. The resistance of the nanotubular array films to scratch was evaluated by performing the microscratch tests with in situ measurement of the contact electrical resistance. To determine their resistance to sliding wear, sliding wear tests were performed in different environments. Compared to wear in air, the wear loss in water significantly decreased. The pH value of water slightly affected the wear loss of TiO2 nanotubular arrays; the results showed that the wear loss of TiO2 nanotubular arrays decreased with increasing pH from 4, through 7, to 10.

Improved Sensitivity of Dual-Axis Micro-Mechanical Probe for Friction Force Microscope

Improvement of the sensitivity of a dual-axis probe for friction force microscopy is presented. The dual-axis micro-mechanical probe combines a double cantilever and torsion beams. This probe could reduce the mechanical cross-talk between the lateral and vertical force detections. In addition, dual-axis forces can be detected by measuring the dual-axis displacement of the probe end using the optical lever-based method. A low reflection region is formed at the probe end. The region is irradiated with an optical lever laser light and the reflected light is focused onto a four-segmented photo diode (PD). The lateral force can be detected by measuring the displacement of the probe end using the dark region displacement on PD. A shallow step structure was used as a low reflection region in our previous study. However, its darkness was not enough and the improvement of the sensitivity was difficult. In this paper, a new type of low reflection region is presented. The low reflection region using a slope-structure could improve the lateral deflection sensitivity by a factor of 1.4 as compared with conventional one. And the minimum detection limits of the lateral deflection and force were of the order of 1 nm and 1 nN, respectively. This leads to accurate investigation of nanotribological phenomena.

302 高精度な摩擦力顕微鏡用二軸独立検出型マイクロ・メカニカルプローブの開発(T01-1 マイクロ・ナノダイナミクスの計測と制御(1),大会テーマセッション,21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

Conventional friction force microscope (FFM) had the disadvantage of low force sensitivity due to mechanical interference between torsion caused by friction force and caused deflection by normal force. We have developed dual-axis micro-mechanical probe. It measures the lateral force by detecting the deflection of the double cantilever and measures the vertical force by the torsion beam. However, the method of calibrating the probe lateral deflection has not been established. In this study, we present a new method precisely which calibrates the probe lateral displacement in order to detect the friction force.

2303 二軸独立検出型摩擦力顕微鏡用マイクロ・メカニカルプローブの高精度化(要旨講演,一般セッション:マイクロナノ理工学)

2303 二軸独立検出型摩擦力顕微鏡用マイクロ・メカニカルプローブの高精度化(要旨講演,一般セッション:マイクロナノ理工学)

Statistical method for evaluating and ranking lubricants through micromechanical heterogeneity mapping of surfaces that experienced lubricated sliding

The requirements for improved fuel economy and reduced vehicle emission have driven the lubricant industry to develop new lubricants for engines and other dynamic systems. The selection of appropriate lubricant formulation is a complicated process involving extensive and costly bench and field tests. Thus, there is a demand for developing quick, effective and less costly methods to evaluate and rank lubricants. The authors previously proposed a statistical technique for evaluating and ranking lubricants through examining spatial variations in local mechanical properties of a worn surface after lubricated sliding testing using a micromechanical probe. Examination of the mechanical heterogeneity of worn surface has been turned out a promising approach for prescreening lubricants before further bench and field tests. Research was conducted to further investigate the suitability of such a method to evaluate lubricant performance during lubricated wear tests for a number of engineering materials and in particular, to identify which mechanical property (e.g. hardness, Young's modulus, creep behaviour) was the most sensitive and reliable indicator of the surface mechanical heterogeneity. Efforts were also made to identify the optimum indentation load range for evaluating the mechanical heterogeneity. It was demonstrated that the statistical method based on the heterogeneity of worn surfaces was effective for evaluating and ranking lubricants. Microhardness was proven to be the most suitable parameter for evaluation of the mechanical heterogeneity of worn surfaces, especially for harder materials.

Dynamic characterization of nanoelectromechanical oscillators by atomic force microscopy

Dynamic detection of vibrational characteristics of nanoelectromechanical systems (NEMS) was investigated through direct coupling with a micromechanical probe. The nanomechanical structures were harmonically driven using piezoelectric transducers and the resulting out-of-plane excitations were monitored with a conventional atomic force microscope (AFM) probe. Intermittent contact imaging data show quantitative linear classical resonance behavior. Additionally, noncontact AFM interrogation revealed the initiation of interaction between the two oscillators, providing a qualitative description of the resonant response. The vibrational spectra measured through optical excitation and detection were in good agreement with the coupled NEMS-AFM system measurement results. The dynamic response of the coupled system was modeled through a combination of long range van der Waals and contact forces using the Derjaguin–Muller–Toporov model. These results collectively demonstrate that this is a viable method for detecting the dynamic behavior of nanoscale suspended mechanical structures.