Copper Debris Research Articles

Research on Detection Performance of Four-Coil Inductive Debris Sensor

The online monitoring of debris in oil can timely and accurately reflect the wear status of mechanical equipment. The inductive debris sensor based on the electromagnetic induction can effectively detect various parameters of debris. The four-coil structure-based of the sensor is theoretically introduced. The optimal coil length, the turns of the excitation coil and the turn ratio are obtained through simulation in order to improve the sensitivity of the inductive debris sensor. The effects of the excitation frequency and the movement velocity, size, position and material of the debris on the sensor output are investigated. The sensing signal recovered by coherent demodulation confirms the sensor’s effectiveness in identifying metal debris. The experiment realized the identification of iron debris with a diameter of 93.5 μm and copper debris with a diameter of 447.3 μm under the 3 mm pipe radius, providing a reference for the design of four-coil inductive debris sensor.

An Ultrasensitive Microsensor Based on Impedance Analysis for Oil Condition Monitoring

Oil condition monitoring is an important way to achieve mechanical equipment health assessment, condition early warning, fault diagnosis, and intelligent maintenance. A microsensor integrated with inductance-resistance and capacitance sensing units is presented, which can comprehensively detect metal debris, air bubbles, and moisture in oil based on impedance analysis. The inductance-resistance sensing unit not only detects traditional inductance parameter, but also proposes a resistance detection method based on coil to further improve the detection sensitivity for nonferromagnetic metal debris. The capacitance sensing unit can detect air bubbles, and a new moisture measurement method is also proposed. Based on the signal characteristics of inductance, resistance and capacitance detection results, the microsensor can effectively distinguish 16–500 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m iron debris, 60–500 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m copper debris, >170 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m air bubbles and moisture in oil. The ultrasensitive microsensor can obtain more oil status information, which has important value and wide engineering application prospect for modern fault diagnosis and prediction theory based on information fusion.

Combined lubrication of surface texturing and copper covering for broaching tool

Broaching is widely used in the aerospace field owing to its high efficiency and heavy load. However, heavy-load cutting causes intense squeezing and friction in the tool-chip contact area, resulting in a lack of lubrication. Therefore, three textures (i.e., micro-pit, stripe, mesh) are prepared on the rake face of broaching tool with a laser processing technique to improve cutting performance. Afterward, textures are covered with copper using the reciprocating rotational friction to enhance the wettability and heat dissipation capacity of the broaching tool. Experiments approve that striped textures covered with copper reduce the cutting force by 14.6% and the cutting temperature decreases from 90.13 to 76.9 ℃, compared with non-textured cutting teeth. Obtained results indicate that the wettability of cutting fluid on the tool surface is significantly improved due to the capillary force of micro-pores generated by the copper covering, especially in the direction to the cutting edge. Furthermore, the copper debris absorbs heat quickly in the cutting areas and is subsequently taken away by chips and cutting fluids, thereby reducing the cutting temperature.

Strengthening mechanisms of aluminum matrix composite containing Cu-coated SiC particles produced by friction stir processing

ABSTRACTA friction stir processing (FSP) method has been developed to fabricate a locally reinforced aluminum matrix composite (AMC) by stirring electroless-copper-coated SiC particles into AA6061 matrix. The interfacial bonding between particulate reinforcement and the matrix was enhanced by the copper coating. Effective improvement in hardness and in tensile strengths has been proved. Microstructural investigation and analyses were conducted to correlate the microstructural evidences with the possible strengthening mechanisms. The effect of copper coating on the bonding between SiC particles and Al-matrix; the role of the dispersed Cu debris and the increased Cu content in solid solution on the strengthening; and the effect of friction stir on dislocation density and on the recrystallization behavior were analyzed. Multiple strengthening mechanisms due to diffusion between copper film and matrix; dispersion of fine copper debris and Al-Cu intermetallic compounds (IMCs) in the matrix; solid solution due to increased copper content and dislocation punching were four major mechanisms in interpreting the strengthening phenomena in AMC containing copper coated SiC reinforcements.

Cavitation occurring in capillary tubes

Surface etches caused by cavitation often occur behind the blade of a rapidly rotating propeller or on a vibrating surface where liquid is subjected to suddenly reduced or oscillating saturation pressure. This phenomenon has never been reported in a continuous capillary pipe in which flow pressure varied gently without injection of external radiation energy. On the other aspect, acoustically tinkling signals were recognized decades ago during operation of the oscillation capillary heat pipe, but lacking of vigorous scientific understanding of the root causes. In this article, we report cavitation and its surface etches in meandering capillary tubes with the inner diameter of 1.8 mm. Numerous etching pits were observed on the interior face at the heat rejection region after over 200 hours operation. Irregular copper debris, with sizes ranging from 20 to 500 μm, is found in the reclaimed operating fluid. Analysis of temperature and acoustic data indicates that, driven by spiking temperature difference, highly turbulent two-phase flow carries the saturated vapor bubbles from the evaporator to the subcooled condensation region in a very short time of oscillation, turning vapor phase into oversaturated status. Rapid condensation accelerated shrinkage of the vapor bubbles causing strong micro jet impingement to damage the pipe wall, radiating acoustical signals.

Microstructure, mechanical and elevated temperature tribological behaviors of the diamond/Cu composites prepared by spark plasma sintering method

Compact diamond/Cu composites with different contents of diamond particles were successfully prepared by the spark plasma sintering method. The tribological properties at elevated temperature of the diamond/Cu composites were studied. Results show that the addition of diamond particles in the Cu matrix could slightly increase the mechanical properties. Hardness and elastic modulus of the diamond/Cu composite with 50 vol% diamond particles reach about 31 GPa and 216 GPa, respectively, which are obviously higher than those of unreinforced copper alloy. The composite with 50 vol% diamond particles exhibits the lowest friction coefficient of 0.133 and lowest wear rate of 2.1–2.7 × 10−6 mm3/Nm at 500 °C. The low friction coefficient of the composite is attributed to the copper debris which can react with moisture to form copper oxide, serving as the lubricant between the contact counterparts.

Friction and Wear Characteristic of Electroplating Cu Coating on 0Cr18Ni9Ti Stainless Steel

In order to improve wear resistance surface on 0Cr18Ni9Ti stainless steel, Cu coating on the 0Cr18Ni9Ti stainless steel substrate was deposited by electroplating technology. The friction and wear properties of 0Cr18Ni9Ti stainless steel substrate and Cu coating were investigated contrastively. The morphologies of the wear scars were analyzed by scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS) and scanning probe microscope (SPM), and the wear mechanism was discussed. The results showed that the wear resistance of Cu coatings was significantly improved as compared to that of 0Cr18Ni9Ti stainless steel substrate. The wear scar of 0Cr18Ni9Ti stainless steel substrate showed flaking pit, and its wear mechanism were delamination and abrasive wear. In case of Cu coating, the wear scars showed morphology of plastic deformation caused by adherent copper debris being pressed, and its wear mechanism were delamination and fatigue wear.

Death by electrocution: Histological technique for copper detection on the electric mark

The current observation of deaths by electrocution, both for domestic and work-related accidents as well as those in other contexts, has deepened the scope of investigation into electric marks, especially from the histological point of view. This is one of the few investigation tools that may lead to the diagnosis of death by electrocution in this distinct area, bearing in mind the diagnostic difficulties that this type of fatality presents.Our attention has been placed on the phenomenon of metallization. In particular, we focused on using the Timm's method [1] to locate the copper deposits. The phenomenon of metallization, usually could be caused by the copper deposit, this happens due to the copper debris released onto the skin by the live conductor. To date, this technique has only been used in the pathological field. Nevertheless, we tried to assess its application in seven selected cases, after partially modifying the technique, comparing it with the most common staining detection techniques and analysing the specificity, sensitivity as well as the potential for its application in the routine.

Research on Experiment and Technique of Material Identification for Debris of Engineering Equipment Based on Computer Vision

Based on micro-image, the material identification of iron and copper debris in working oil of engineering equipment is researched. By selecting four characteristic parameters of debris image, a debris recognition classifier is designed based on multi-SVM. The materials and types of debris can be fast identified after the model is trained and the identification accuracy is high, thus a new method for fault diagnosis of engineering equipment is provided.

A method to monitor non-ferrous debris in ferrographic analysis

Non-ferrous debris in oil sample provide important information about the wear condition of a wear couple containing non-ferrous metal components. In order to collect wear debris of non-ferrous metal material more effectively and deposit them on a ferrogram in a stable depositing ratio, the method of employing magnetic fluid as a magnetization agent to collect non-ferrous wear debris in ferrography was attempted. Magnetic fluid constituting Fe3O4 magnetic particles was prepared using a precipitation reaction. Tetrachloroethylene was used as a carrier liquid to ensure that magnetic fluid can be easily mixed with lubricant oil sample. Oleic acid was used as a surfactant, which enables magnetic particles to adhere to the surface of non-ferrous wear debris. Then the non-ferrous wear debris was magnetized and deposited on a ferrogram in a stable depositing ratio. Copper debris was chosen as an example of non-ferrous debris to illustrate the magnetization effect of the magnetic fluid. With the help of magnetic fluid, the ferrographic analyst will achieve the operating condition of the machine more accurately.

Laser copper plasma X-ray source debris characterization

Laser copper plasma sources are a compact, economical means of producing high intensity X-rays at the correct wavelengths for X-ray lithography. Copper debris in the form of vapor, ions, dust, and ...

Effect of composition on friction coefficient of Cu–graphite composites

Cu–graphite composites were prepared by hot isostatic pressing from the copper and graphite powders in the range of 0–50 vol.% of graphite. The same graphite powder was copper coated and used for the preparation of coated composites with 30 and 50 vol.% of graphite. It was confirmed that with increasing concentration of graphite the coefficient of friction and wear rate of coated and uncoated composites at first decreases. When critical concentration threshold of graphite is reached the coefficient of friction of composites becomes independent on the composition while the wear rate decreases further. This threshold is not simply 20 vol.% of graphite as stated [P.K. Rohatgi, S. Ray, Y. Liu, Tribological properties of metal matrix graphite particle composites, Int. Mater. Rev. 37 (1992) 129–149.] for metal matrix composites, but it significantly depends on the composite structure: for uncoated composites, it is 12 vol.% of graphite for fine graphite powder (16 μm), while for coarse powder (25–40 μm, [S.F. Moustafa, S.A. El-Badry, A.M. Sanad, B. Kieback, Friction and wear of copper–graphite composites made with Cu-coated and uncoated graphite powders, Wear 253 (2002) 699–710.]) it is 23 vol.% of graphite. For coated composites the concentration threshold was found above 25 vol.% of graphite. The reason is that the increased number of fine copper debris within graphite rich tribolayer occurs homogeneously also at high graphite composition.

Laser copper plasma X-ray source debris characterization

Laser copper plasma sources are a compact, economical means of producing high intensity X-rays at the correct wavelengths for X-ray lithography. Copper debris in the form of vapor, ions, dust, and high speed particles is an unwanted byproduct of the laser copper plasma technique. Improved methods for debris mitigation are essential for production X-ray lithography using laser copper plasma sources.The main objective of this project is to characterize the debris, particularly the size, amount, and velocity spectrum of high speed particles. The measurements used a source-laser-pulse-synchronized high speed spinning disc. An optical scanning boom microscope analyzed debris collected on a target. Kinematic triangulation using the location of the debris indicates the velocity of debris particles.Velocities of copper debris particles were found to be in the hundreds of meters per second, roughly one order of magnitude slower than previously believed. The precision of results was limited by a mismatched sampling rate for particle collection. This discovery opens up the possibility of a host of mechanical debris blocking countermeasures previously thought to be too slow to effectively stop high speed debris particles. This study also suggests that X-rays emitted at high laser pulse rates could be blocked by debris generated during the previous laser pulse. An area requiring further refinement and study is in the mechanics of plasma generation. The target location and laser spot size and focal point are critical factors in the process and have a low tolerance for variation.

Copper metallurgy as a diagnostic tool for analysis of the origin of building fires

Copper debris originating from electrical wiring, fixtures, or electrical machinery, is frequently found in building fire residues. Changes in macro- and microstructure of this copper can be explicitly related to exposure temperature, time, ambient oxygen or foreign materials, mechanical stress, and the initial condition of the metal. The circumstances under which such changes can or cannot be regarded as proof of the cause and origin of the fire are outlined.