Wear Rate

‫د‬ . ‫داوود‬ ‫خنساء‬ ‫الشمري‬ -‫د‬ . ‫الزبيدي‬ ‫باسم‬ ‫اسيل‬ -‫الحسن‬ ‫عبد‬ ‫خالد‬ ‫اﻝﻤﻠﺨص‬ ‫درﺠﺎت‬ ‫ﻋﻨد‬ ‫اﺠﻌﺔ‬ ‫اﻝﻤر‬ ‫اء‬ ‫إﺠر‬ ‫ﺜم‬ ‫ﻴت‬ ‫ﺒﺎﻝز‬ ‫اﻝﺘﻘﺴﻴﺔ‬ ‫ﺘﺄﺜﻴر‬ ‫اﺴﺔ‬ ‫در‬ ‫إﻝﻰ‬ ‫اﻝﺒﺤث‬ ‫ﻴﻬدف‬ ‫ﻴﺔ‬ ‫ار‬ ‫ﺤر‬ C°180 ‫و‬ C ° 400 ‫ﻝﻔوﻻذ‬ ‫اﻝﺒﻠﻰ‬ ‫ﻤﻌدل‬ ‫ﻋﻠﻰ‬ Cr 6 100 . ‫اﺴﺘﺨ‬ ‫وﻗد‬ ‫ات‬ ‫وﻓﺘر‬ ‫ﻤﺨﺘﻠﻔﺔ‬ ‫أﺤﻤﺎل‬ ‫ﺘﺴﻠﻴط‬ ‫ﻋﻨد‬ ‫اﻝﺒﻠﻰ‬ ‫ﻤﻌدل‬ ‫ﻝﻘﻴﺎس‬ ‫اﻝﻘرص‬ ‫ﻋﻠﻰ‬ ‫اﻝﻤﺴﻤﺎر‬ ‫ﺘﻘﻨﻴﻪ‬ ‫دﻤت‬ ‫ﻻق‬ ‫اﻻﻨز‬ ‫ﺴرﻋﻪ‬ ‫ﺘﺜﺒﻴت‬ ‫ﻤﻊ‬ ‫ﻤﺨﺘﻠﻔﺔ‬ ‫اﻨزﻻق‬ ) 2.199m\sec ( ‫اﻝﻔوﻻذي‬ ‫اﻝﻘرص‬ ‫وﺼﻼدة‬ 45HRC . ‫ﻝﻼﻨزﻻق‬ ‫اﻝزﻤﻨﻴﺔ‬ ‫ة‬ ‫اﻝﻔﺘر‬ ‫و‬ ‫اﻝﻤﺴﻠط‬ ‫اﻝﺤﻤل‬ ‫ﻴﺎدة‬ ‫ز‬ ‫ﻤﻊ‬ ‫ﻴزداد‬ ‫اﻝﺒﻠﻰ‬ ‫ﻤﻌدل‬ ‫ان‬ ‫اﻝﻨﺘﺎﺌﺞ‬ ‫أظﻬرت‬ ‫وﻗد‬ . ‫وﻜذﻝك‬ ‫اﻝﻨﺘﺎ‬ ‫اظﻬرت‬ ‫ة‬ ‫ار‬ ‫ﺤر‬ ‫درﺠﻪ‬ ‫ﻋﻨد‬ ‫اﺠﻌﺔ‬ ‫اﻝﻤر‬ ‫و‬ ‫ﻴت‬ ‫ﺒﺎﻝز‬ ‫اﻝﻤﻘﺴﺎة‬ ‫اﻝﻌﻴﻨﻪ‬ ‫ان‬ ‫ﺌﺞ‬ C° 400 ‫ﺒﻠﻰ‬ ‫ﻤﻘﺎوﻤﻪ‬ ‫ذات‬ ‫ة‬ ‫ار‬ ‫ﺤر‬ ‫درﺠﺔ‬ ‫ﻋﻨد‬ ‫اﺠﻌﺔ‬ ‫اﻝﻤر‬ ‫و‬ ‫ﻴت‬ ‫ﺒﺎﻝز‬ ‫اﻝﻤﻘﺴﺎة‬ ‫اﻝﻌﻴﻨﺔ‬ ‫ﻤﻊ‬ ‫ﻨﺔ‬ ‫ﺒﺎﻝﻤﻘﺎر‬ ‫أﻋﻠﻰ‬ C°180 .

The use of Nitrile Butadiene Rubber NBR as seal in machines has increased in recent years. NBR is considered as the standard material for sealing and NBR owes its many applications to a range of special mechanical properties. However, the non-linear mechanical properties and incompressible behaviour of NBR make the analysis of NBR very difficult. The most common technical cause of hand pump failures was the wear of the piston seals. Contact surface of the piston seals and the piston seal contact area are the key of calculating and determining friction force and seal wear rate of hand pump NBR rubber piston seal.

In this work application of Micro cellulose fibre in brake pad composites were successfully carried out. Micro cellulose fibres were modified with 3-aminopropyltriethoxy-silane before using in the brake pad. Four different brake pads were prepared using compression moulding process with the different ratio of micro cellulose fibre along with, phenolic resin, barium sulphate, aluminium oxide and graphite. Properties of prepared brake pads were evaluated in terms of density, water and oil soaking test, compressive strength, hardness, flame resistance, wear rate, X-ray diffraction, thermogravimetric analysis, the coefficient of friction and scanning electron microscope. Brake pad composition with 10% weight of micro cellulose fibre showed the promising result with respect to other attempted compositions and are comparable to commercial sample.

"Al–Cu-based MMCs reinforced by Al–Fe intermetallics are investigated for their wear behaviour. The composite (Al–4.5 mass% Cu–3.4 mass% Fe) was produced by solidification processing where the Al–Fe-based intermetallic formed in situ in a matrix of mainly Al–Cu alloy. The effects of thermal and mechanical processing, viz., as-cast condition, solution treatment, aging and hot rolling on the wear behaviour of the composites were examined. The composites were characterized by optical microscopy, SEM, microhardness measurements and X-ray diffraction. The wear behaviour of the composites was studied in a pin-on-disc type wear apparatus.

The as-cast in situ composite exhibited the highest wear rate. The wear rate of the (cast + solution treated + aged) composite was about 4.5 times and that of the (rolled + solution treated + aged) composite about 9.5 times lower than the wear rate of the as-cast composite. Hot-rolling + solution treatment + ageing of the MMC was found to yield the lowest wear rate among all processing conditions investigated. Worn surface revealed that mainly abrasive wear took place in all cases. The extent of abrasive wear was largest in the as-cast MMC as evidenced by deep groves on the worn surface as well as by the highest weight loss. Dark patches of presumably transfer layer were found in some cases, particularly on the (rolled + solution treated + aged) samples. Attempt has been made to relate the wear behaviour of the in situ MMC to their microstructures and to the microhardness of the matrix and the reinforcing phase."

In the present study, the Al2219, Al2219/ B 4 C & Al2219/B 4 C/MoS 2 hybrid composites are investigated under dry sliding wear test as for ASTM G 99-95 standard. Al 2219 base matrix reinforced with B 4 C & mixture of B 4 C and MoS 2 are fabricated using stir casting technique. By using pin on disc apparatus the test was conducted by taking parameters like sliding distance, sliding velocity and loads. The result reveals that the addition of B 4 C slightly reduces wear rate of composites, further B 4 C and MoS 2 reinforcement decreases the wear rate of the hybrid composites and increases the wear resistance of the composites. The wear rate decreases with increasing the % of MoS 2 . At a lower sliding velocity the wear rate decreases and as the sliding velocity increases the wear rate increases. As the sliding distances and load increases the wear rate drastically increases.

There are three most concerned properties In the quality of biomedical devices, mechanical properties, durability and biocompatibility . The failure modes of biomedical devices can be mainly divided into thrombosis, infection, inappropriate healing, structural failure, adverse local tissue interactions, migration and systemic and miscellaneous effects. Each failure mode has negative effects on some (or all) of the quality properties. Tests for biomedical devices can be summarized as mechanical tests and biological tests. Mechanical tests are used to test mechanical properties and durability while biological tests are used to test biocompatibility and durability. Different kinds of tests focus on studying different failure modes, in some ways, evaluating the reliability of biomedical devices from different angles. Based on reliability-centered systems engineering which focus on dealing with failure and the unique property of biomedical devices, i.e. biocompatibility, the concept of failure is extended and the clear definition of the reliability of biomedical devices is given.

The present work focuses on the effect of reinforcing polymer with TiO 2 and Al 2 O 3 Nano-powders on its thermal properties since they have many important thermal applications. The effect of adding such Nano-powders with different particle percentages by weight (0.5%,1%, 1.5% and 2%) to the base material have been discussed. Different samples of the resulting Nano-composite materials have been prepared according to (ISO-220077) standard. Thermal properties of such samples have been evaluated by using hot disc technique and the results have been compared with that of pure epoxy. The results show that the thermal conductivity and thermal diffusivity increase with increasing weight fraction of reinforcing materials, and it becomes higher when the epoxy was reinforced by (Al 2 O 3) rather than (TiO 2) Nano powder. Also the results indicated that maximum values of thermal conductivity and diffusivity of the Nano-composite specimen reinforced by 2% (Al 2 O 3) were (0.55W/m.K) & (0.45 mm 2 /Sec.) respectively. It has also shown that the heat capacity of the Nano-composite material decreases when the epoxy reinforced with Al 2 O 3 and TiO 2 Nano-powders with different weight fractions.

The present work aims at the development of particulate metal matrix composite using Aluminum alloy (AL 7075) as the matrix material and alumina (Al 2 O 3), Silicon Carbide (SiC) and Hybrid (Al 2 O 3 +SiC) as Reinforcement. Al 2 O 3 is reinforced in the weight fraction of 3%, 6%, 9% and 12% with the particle size varying between 50 microns to 150 microns. SiC in the weight fraction of 3%, 6%, 9% and 12% & Al 2 O 3 +SiC in the weight fraction of 3%+3%, 6%+3%, 9%+3% and 12%+3%. The aluminum alloy was melted at 700°C in an electrical heating furnace for 20 minutes and the reinforcement is heated separately at 350° C was added in the form of powder. The molten metal was stirred for 5 minutes at the temperature of 700°C, followed by pouring in to the metal mold. Optical micro graph of the developed composite was obtained to demonstrate the distribution of the reinforcement in the matrix. The hardness tests was carried out to determine the effect of reinforcement on the hardness of the composites. The hardness of the composite was found increases with the increase in reinforcement weight fraction. The wear test carried out at various speed, load and sliding distance which indicates improvement in the mechanical properties of the composites. The wear resistance of the composite reduces with the increase in the Reinforcement weight fraction. The wear resistance reduces with the increase in speed, Also wear rate increases with the increase in applied load. As the sliding distance increases the wear of the MMC increases for all specimens. The coefficient of friction was reduces at higher weight fraction as compared to lower weight fraction of reinforcements.. The noise during running the test was reduced in case of Hybrid composite as compared to composite with either alumina or silicon carbide as reinforcement. The investigation carried out will lead to development of the composite system with high strength, improved wear resistant, light weight for automobile parts like disc brake, piston, cylinder liner, drive shaft etc.

In railway systems, certain atmospheric conditions-mainly related to temperature and relative humidity-lead to the creation of iron oxides which can affect the coefficient of friction between the wheel and the rail. This can result in increased wear of the rail, reducing its service life and thus increasing replacement costs. Pin-on-disc tests were conducted in a climate chamber to study the influence of environmental conditions and iron oxides on the coefficient of friction. The iron oxides generated on the surface of specimens extracted from microalloyed rail steel during wear tests were analysed using X-ray diffraction. The results show that hematite (α-Fe 2 O 3) is the predominant iron oxide among all the oxides generated on the worn surfaces. It was further noted that the oxide layer resulting from the rise in both temperature and relative humidity does not significantly affect the average coefficient of friction for each steel samples tested. High relative humidity combined with high temperature leads to the formation of α-Fe 2 O 3 , which tends to increase the coefficient of friction. However, a boundary lubrication effect is observed at higher relative humidity due to a condensed water film, which reduces the coefficient of friction and counteracts the increase of the coefficient of friction expected due to the presence of hematite.

Investigation is carried out to improve the tribological properties of the ZA-27 alloy by adding 10% copper and adding copper it is called as modified ZA-27 alloy. The wear behaviour of the modified ZA-27 alloy was studied by performing dry sliding wear test using pin-on-disc and wear is monitored by varying the load and sliding speed. Results show that addition of Cu in the ZA-27 alloy has better wear resistance than the plain ZA-27 alloy. Sliding speed of 1.5 m/s can be considered as critical sliding speed for all loads. Coefficient of friction is decreased with increase in the normal load and sliding speed where as frictional force is increased with the normal load and decrease with the sliding speed.

In present work, the wear behaviour of extruded AZ31B magnesium alloy during dry sliding conditions has been investigated. The experiments were carried out using a pin-on-disc type wear apparatus against a steel disc counter face in an applied load range of 10-50 N, sliding velocity range of 0.1-0.9 m/sand at a constant sliding distance of 1000 m. The effect of applied load and sliding velocity on wear rate were analyzed. The wear surfaces were examined using a scanning electron microscope equipped with an energy dispersive spectrometer to reveal wear features. Wear mechanisms were analyzed at different sliding conditions. They were abrasion, oxidation, delamination, plastic deformation and melting.

The study of wear is generally focused on reproducing micromechanisms that are identified on industrial applications in the laboratory. To do so, many tribometers have been developed, but not much attention has been given to the correlation among the variety of abrasive test results. This study aims to compare four different abrasive wear tests: pin-on-disc, single pass pendulum, linear scratch and the laboratory of tribology and materials test. High chromium white cast irons were tested in different conditions. It was observed that the wear resistance classification offered by the pendulum scratch and the laboratory of tribology and materials test was the same and was the opposite of the classification offered by the scratch and pin-on-disc tests. The wear rate behaviour verifies the existing constant depth and constant load models regarding the force transferred to the contact region. For the latter, the wear behaviour is better explained by the product k*q, parameters that are obtained from the pendulum test.

This technical paper describes the abrasive wear rate of as-cast and heat-treated Al (6061) alloy reinforced with 9% by weight of SiC particulate and 0, 1, 3 and 5% by weight of E-glass fibre subjected to different ageing durations. The liquid melt technique route is used to produce the castings. Castings were machined to the ASTM standards and T6 heat-treatment process is carried out. All the specimens were artificially aged to different durations like 1, 3, 5 and 7 h at a temperature of 175 • C. Wear tests were performed on various composites in both the heat-treated and as-cast conditions using pin-on-disc machine. In each test the wear rates of the hybrid composites were found to decrease with increase in ageing durations. However, in both as-cast and heat-treated hybrid composites, the wear rate increased with increase in the sliding distance.

This paper investigates the wear behavior of magnesium (Mg)-based metal–matrix composites (MMCs) reinforced with silicon carbide and aluminium oxide particulates (SiCp) during dry sliding. Experiments were conducted using a pin-on-disc configuration against a hardened tool-steel counter face under load of 3kg, and with disc rpm 500, wear track diameter 60mm, time 5min..Two samples were tested on pin on disc wear and friction monitor. The results showed that an alloy similar to the commercially available composition of AZ61 reinforced with 3% SiC&1% Al2O3 exhibit superior wear resistance as compared to magnesium alloy AZ61 reinforced with 1% SiC&3%Al2O3.Fabrication of metal matrix composites were done using stirr casting technique.

During the last two decades, the industry (including scientists) has focused on diamond-like carbon (DLC) coating because of its wide range of application in various fields. This material has numerous applications in mechanical, electrical, tribological, biomedical, and optical fields. Severe friction and wear in some machine parts consumes high amount of energy, which makes the process energy inefficient. Thus, DLC coating can be an effective means to lower the friction and wear rate. Some important process variables that affect the tribological characteristics of DLC coating are adhesion promoter intermediate layer, substrate surface roughness, hydrogen incorporation or hydrogen non involvement, and coating deposition parameters (e.g., bias voltage, etching, current, precursor gas, time, and substrate temperature). Working condition of DLC-coated parts also affects the tribological characteristics, such as temperature, sliding speed and load, relative humidity, counter surface, and lubrication media (DLC additive interaction). Different types of lubricated oils and additives are used in engine parts to minimize friction and wear. DLC can be coated to the respective engine parts; however, DLC does not behave accordingly after coating because of lubricant oil and additive interaction with DLC. Some additive interacts positively and some behave negatively because of the tribochemical reactions between DLC coating and additives. Numerous conflicting views have been presented by several researchers regarding this coating additive interaction, resulting in unclear determination of true mechanism of such interaction. However, lubricant additive has been established to be more inert to DLC coating compared with uncoated metal surface because the additive is fabricated in such a way that it can react with metal surfaces. In this article, the tribological characteristics of different types of DLC coating in dry and lubricated conditions will be presented, and their behavior will be discussed in relation to working condition and processing parameters.

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This article reveals the wear rate and electrical conductivity of composites made of carbon powder and waste of glass bottle with a phenolic resin matrix. The study was initiated with a carbonization of coconut shell, pulverized and filtered the carbon and waste glass bottles to reach the mesh size of  300. Both materials were mixed with a composition ratio of carbon: glass, 70%:30%; 80%:20%; and 90%:10% weight. The mixture was mixed with phenolic resin adhesive and compacted with a load of 5 US ton. Results showed, the higher the carbon content, resulting in the higher the electrical conductivity, but also showed the lighter composite. Increased content of carbon powder made lighter composite, it also made the softer composite, so that the higher wear rate. Lowest wear rate was showed by a mixture of carbon-glass composite with a composition ratio of 70:30, which was 6.86738E-06 mm 3 /Nm. Carbon powder was softer than glass powder, the highest rate was indicated by the carbon-glass composite with 90:10 composition, which was 8.67425E-06 mm 3 /Nm. A high content of carbon powder encouraged an increase electrical conductivity of the composite. Mixture of carbon-glass composite with the composition ratio of 90:10 produced electrical conductivity of 0.192 S/m. composite produced the lowest wear rate of 1.3 mg·min -1 and a maximum of 20.3 mg·min -1 [2]. Tangle of long fibers of carbon from PAN soaked in adhesive mixtures containing nano particles of TiO 2 , CaCO 3 and SiO 2 , resulting in wear rate decreased, compared to the composite of woven carbon fiber only . Polyamide carbon fiber-reinforced composites has been studied, the composite produced wear rate of 2-4 × 10 -6 mm 3 /Nm . PAN-based carbon fibers were used as reinforcement fibers in carbon-carbon composites with matrix of pitch produced wear rate of 1 to 2.5 m/s/f [5]. Wear-resistant carbon-carbon composite material was ever made of carbon powder of coal waste with coal tar pitch matrix, the hot press process, the composite produced the lowest wear rate is 0.00087 (10 -7 mm 2 /kg) . Engineering composites of carbon

Friction and wear behaviors of ball bearings made from carbon-chrome steel were experimentally simulated using a modified ball-on-disc tribometer. The test was performed over a broad range of applied loads (W), sliding velocities (v) and sliding distances (L) under gas lubricated conditions using a Taguchi method. The results found that gas blown to the sliding surfaces in air effectively reduced the coefficient of friction as compared with the air lubrication at higher applied load, sliding speed and sliding distance. In addition, a specific wear rate is constant throughout the tests under gas lubricated conditions. However, under air lubrication, the specific wear rate decreases with increasing applied load, sliding speed and sliding distance. By using the optimal design parameters, a confirmation test successfully verify the N2-gas lubrication reduced average coefficient of friction and simultaneously improved wear resistance about 24 % and 50%, respectively. This is in accordanc...

The present work describes the surface improvement and biocompatibility of TiAl 24 Nb 10 intermetallic alloy using rf plasma nitriding. The nitriding process was carried out at different plasma power from 400 W to 650 W where the other plasma conditions were fixed. Grazing incidence X-ray diffractometry (GIXRD), Auger electron spectroscopy (AES), tribometer and a nanohardness tester were employed to characterize the nitrided layer. Further potentiodynamic polarization method was used to describe the corrosion behavior of the un-nitrided and nitrided alloy. It has been found that the Vickers hardness (HV) and corrosion resistance values of the nitrided layers increase with increasing plasma power while the wear rates of the nitrided layers reduce by two orders of magnitude as compared to those of the un-nitrided layer. This improvement in surface properties of the intermetallic alloy is due to formation of a thin modified layer which is composed of titanium nitride in the alloy surface. Moreover, all modified layers were tested for their sustainability as a biocompatible material. Concerning the application area of biocompatibility, the present treated alloy show good surface properties especially for the nitrided alloy at low plasma power of 400 W. #

In railway systems, certain atmospheric conditions – mainly related to temperature and relative humidity – lead to the creation of iron oxides which can affect the coefficient of friction between the wheel and the rail. This can result in increased wear of the rail, reducing its service life and thus increasing replacement costs. Pin-on-disc tests were conducted in a climate chamber to study the influence of environmental conditions and iron oxides on the coefficient of friction. The iron oxides generated on the surface of specimens extracted from microalloyed rail steel during wear tests were analysed using X-ray diffraction. The results show that hematite (α-Fe2O3) is the predominant iron oxide among all the oxides generated on the worn surfaces. It was further noted that the oxide layer resulting from the rise in both temperature and relative humidity does not significantly affect the average coefficient of friction for each steel samples tested. High relative humidity combined w...

In this paper, Friction Stir Processing was used to process the surface of aluminum 5052. Different tool rotating speeds and tool traverse speeds were combined and were then used for the study. Micro-hardness and wear tests were performed on the surface of Al5052 after FSP and the results were then compared to the base metal without FSP. Results showed that the samples processed with FSP provided better micro-hardness values as compared to the base material. The wear test as well as the coefficient of friction was performed and showed better results than the parent material without FSP

Estão em desenvolvimento novos materiais para utilização em rodas ferroviárias, isto devido ao problema de descarte relacionado com os desgastes que as rodas sofrem durante o serviço. Para entender o que ocorre com as rodas ferroviárias foram estudados nesta monografia a mecânica do contato e o desgaste em aços, verificando as várias teorias e os mecanismos que os diferenciam em suas características e proveniências. Porém infelizmente existe uma grande defasagem de pesquisas de desgastes em rodas. O objetivo geral deste trabalho é correlacionar valores de taxas de desgaste retirados da literatura, com os parâmetros utilizados nos ensaios tribológicos. Foi feito uma base de dados com resultados de diferentes aços, com estes dados, foi possível usar o método de correlação para determinar a influência de parâmetros como a carga aplicada no ensaio, a velocidade, a distância percorrida, o meio no qual é realizado o ensaio e a influencia do tratamento térmico. Correlacionando sempre uma destas variáveis com a taxa de desgaste. Concluiu-se que é necessário desenvolver um padrão para os parâmetros dos ensaios, com intuito de relacionar as variáveis com os resultados e mensurar o desempenho do material no que se refere a resistência ao desgaste.