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Traditionally, there are several kinds of method for restraining wear. Usually, it includes the choice of the best operating conditions, the surface coating, the surface heat treatment, and the choice of the best lubricants. Among these methods, only the choice of the best lubricants has the mendable process of chemical element for worn surface, others do not have the mendable process. Consequently, this project proposes a method of continuous tribo-plating, and takes preliminary experiments by using SUJ2 ball specimen and S45C disk specimen to investigate the effects of rotational speed, anode¡¦s density of current, and specimen¡¦s surface roughness on the coating growing rate and the coefficient of friction. Results show that the coating growing rate increases with increasing rotational speed and anode¡¦s density of current, but it doesn¡¦t be influenced by surface roughness. According to the experimental results, it is found that the frictional coefficient in order is uncoated specimen, coated specimen, and continuous coated specimen. Furthermore, at continuous tribo-plating test, specimen whose surface roughness is rough has lower frictional coefficient. According to the analyses of surface pattern and composition, specimen whose surface roughness is rough remains a lot of piece-like coating film on the surface, and this residual film provides a good effect of lubrication. The result of this project proves that continuous tribo-plating not only reduces frictional loss but also has the mendable process of worn surface.

This dissertation presents a series of studies that describe the impacts of, among other things, temperature and kinematics on inter-level dielectric (ILD) and metal chemical mechanical planarization (CMP) processes. The performance of CMP is often evaluated in terms of removal rate, uniformity, planarization length, step height, defects and resulting topography such as erosion and dishing. The assessment of these parameters is significantly dependent on the selection of tool and consumable set (polishing pad or slurry type), as well as the kinematics involved in the process. Variations in pressure, sliding velocity, temperature and slurry flow rate are just a few of the dynamic inputs that can affect polishing performance. The studies presented in this dissertation focus on some of these external parameters and how they influence the mechanisms involved with the CMP process and their overall outcome on performance.Studies presented in this dissertation include topics such as the effects wafer-ring configurations and wafer geometries on the applied wafer pressure distribution across a wafer surface. In addition to this, another study related to understanding applied wafer pressure investigated the estimation of the effective (envelop) pressure for patterned shallow trench isolation (STI) wafers during CMP. When considering the regularity of issues such as changing wafer geometries and wafer feature patterns, these two studies provided significant insight on the potential issues that could arise during CMP when dealing with such events, as well as potential solutions for controlling such events.Another study in this dissertation investigated the effects of polishing pad type on dielectric CMP performance. Polishing pads varied in thickness and grooving, and tests were done to characterize the tribological and thermal behavior of the pads under a wide range of p × V and slurry flow rate conditions. Of key importance in this study was observing any combined effects between changes in platen set point temperature and pad type on ILD removal rate.The greatest contribution to this dissertation involved studies related to the role of temperature in CMP. These studies implemented variable platen set point temperatures to further understand the thermal effects on parameters such as removal rate and coefficient of friction (COF). As a result of these studies, a new removal rate model based on flash heating was developed to describe observed non-linear trends in removal rate. The application of this model has shown great utility in removal rate prediction when compared to prior models.

The main aim of this research was to investigate the mechanism of cavitation in conforming and partially conforming tribological conjunctions. The effect of cavitation on load carrying capacity and frictional performance of is also investigated. This is important with regards to fuel efficiency in internal combustion (IC) engines. Friction accounts for 15–20% of IC engine losses. The piston–cylinder system contributes to 40–50% of these, with the compression ring(s) being responsible for most of this. This is because the primary function of the ring is to seal the combustion chamber, thus small emerging gaps lead to increased friction. In fact, compression ring(s) expend 3–5% of engine input fuel energy. The share of frictional losses of engine bearings is approximately 20–25%. Traditionally, prediction of performance of tribological conjunctions has been studied using Reynolds equation. When the effect of cavitation is considered, various cavitation algorithms with associated boundary conditions for lubricant rupture and reformation are proposed. These include Elrod, and Elrod and Coyne algorithms, as well as boundary conditions such as Swift-Stieber, JFO and Prandtl-Hopkins. There are a number of assumptions embodied in these approaches, as well as the use of Reynolds equation itself. These approaches do not uphold the continuity of mass and momentum in multi-phase flow, in cavitation beyond the lubricant film rupture. A detailed methodology for multi-phase flow, comprising simultaneous solution of Navier-Stokes, energy and lubricant rheological state equations is developed.

The aim of this thesis work was to design and evaluate a wear test method for cemented carbides inserts used in rotary drilling. An appropriate in-house wear test method would provide a better understanding of the wear mechanisms limiting tool life in real drilling. The test method should be easy to use and be able to distinguish between wear of insert materials with different microstructure and properties. The literature study showed few published articles about wear tests and mechanisms concerning rotary drill bit inserts. These methods included two standard wear tests; ASTM G65 and ASTM B611. Furthermore, a modified ASTM G65 test was found as well as an impact-abrasion test. In this work the modified ASTM G65 test, using a rock counter surface, was evaluated in order to understand if the method would mimic the wear of cemented carbides used in rotary drilling. The test method was further developed and showed high repeatability. Measured weight losses showed that the test could distinguish between two common rotary grade materials with a small difference in hardness but with different microstructures. The wear of the tested materials was analyzed with scanning electron microscopy and compared with rotary drill bit inserts collected from the field. The modified test method proved able to produce wear by mechanisms very similar to those found on field worn inserts. Identified wear mechanisms included cracking, fragmentation and spalling of WC grains as well as embedded fragments of WC grains on the surface. In addition, the binder phase was removed and adhered material from the counter surface was detected.

This thesis work sought to find a tribological testing method suitable for cementedcarbide drill bit inserts used when drilling rock. A review of the literature publishedon the matter showed that there are quite a few test methods developed for wearstudies with cemented carbides, but most of them were not designed for the rockdrilling industry. Published studies performed with the found methods and articleswith analyzed field tests have been studied. It is generally agreed upon that the stepsof wear is that the binder disappears first, followed by removal of carbide grains. Themechanisms of binder phase and carbide grain removal is somewhat debated, butalmost every study observes fracture of the carbide grains. The wear test created inthis thesis was shown to give wear linear with time, but not with load. The newmethod was shown to be capable of distinguishing between different cementedcarbides worn in three body abrasion against different rocks. Analysis of the wornsamples shows that there are similarities with bit inserts worn in field testing. Many ofthe observations made during the analysis are also similar to observations inliterature.

This thesis work is performed at Sandvik Mining Rock Tools, a world leading supplier of rock drilling tools. The work is part of developing a new tribological wear test method for cemented carbide drill bit inserts. The test method has earlier been judged successful in mimicking the rotary-percussive rock drilling process because it gives the same wear mechanisms as have been observed for inserts used in rock drilling. During testing the cemented carbide drill bit insert is pressed against a moving rock surface while water and particles are added to the contact area. The particles are present to simulate the rock crushings formed during drilling. They are believed to cause abrasive wear of the inserts. In this work the effect of load, particle material and particle size are studied. When adding silica particles, which are softer than the cemented carbide material, no correlation is obtained between wear rate and load or particle size. Cracking of WC grains, added rock material and removal of pieces of carbide material are seen at the worn sample surfaces. These observations are similar to observations described in other works about wear of cemented carbide. Adding alumina particles, which are harder than the sample material, gives high wear rate and ground/striped sample surfaces. The wear rate increases with alumina particle size.

Abstract This study proposes a model to predict the effect of lubricant starvation on EHL behavior of line contact, including the boundaries among the starved, fully flooded, and over-flooded lubrications. A pre-inlet region is analyzed to overcome the discontinuous phenomenon of film thickness at the position of the meniscus presented in the previous model under the starvation. The relationship between the film thickness of the supply region and the position of the meniscus is established. The prediction formulas for the minimum film thickness required to achieve the fully flooded condition is expressed in terms of the load and the speed. This formula can be used to predict the fully flooded/starved boundary under certain of flow rate in the supply end. In the analysis of the pre-inlet region, the surface speed, the pressure and the mass flow rate are assumed to be continuous with the supply region and the pressure region, so that its film thickness can be calculated by the mass flow rate equation. However, when the backflow occurs in the boundary between the pre-inlet and pressure region, only part of the film thickness flows into the pressure region, and the rest film only performs recirculation. When no backflow is observed at this boundary, the film thickness in the pre-inlet region easily rises and continuously connects to the pressure region. If the film thickness in the supply end is increased, the surface speed gradually decreases at the inlet end of the pre-inlet region. When the film thickness in the supply end increases to twice as high as the minimum film thickness that required to achieve the fully flooded condition, the surface speed at the inlet end of the pre-inlet region becomes stationary. Hence, when the film thickness in the supply end continues to increase to more than twice, the backflow occurs at the supply region, and this behavior is called the over-flooded lubrication.