Influence of Al2O3 reinforcement on the abrasive wear characteristic of Al2O3/PA1010 composite coatings

In the present study, the abrasive wear characteristics of Al₂O₃/PA1010 composite coatings were tested on the turnplate abrasive wear testing machine. Steel 45 (quenched and low-temperature tempered) was used as a reference material. The experimental results showed that when the Al₂O₃ particles have been treated with a silane coupling agent (γ-aminopropyl-triethoxysilane), the abrasive wear resistance of Al₂O₃/PA1010 composite coatings has a good linear relationship with the volume fraction of Al₂O₃ particles in Al₂O₃/PA1010 composite coatings and the linear correlation coefficient is 0.979. Under the experimental conditions, the size of Al₂O₃ particles (40.5-161.0 μm) has little influence on the abrasive wear resistance of Al₂O₃/PA1010 composite coatings. By treating the surface of Al₂O₃ particles with the silane coupling agent, the distribution of Al₂O₃ particles in PA1010 matrix is more homogeneous and the bonding state between Al₂O₃ particles and PA1010 matrix is better. Therefore, the Al₂O₃ particles make the Al₂O₃/PA1010 composite coatings have better abrasive wear resistance than PA1010 coating. The wear resistance of Al₂O₃/PA1010 composite coatings is about 45% compared with that of steel 45.     

纳米SiO2对火焰喷涂尼龙1010涂层干摩擦磨损性能的影响

为了探讨纳米SiO2(n-SiO2)对火焰喷涂尼龙(PA)1010涂层干摩擦磨损性能的影响,采用MRH-3型环-块摩擦磨损试验机对不同n-SiO2含量的尼龙1010涂层的干摩擦磨损性能进行了测试;并利用扫描电子显微镜(SEM)对复合涂层的磨损表面进行观察,以探讨n-S iO2对火焰喷涂尼龙1010涂层摩擦磨损性能的影响机制。结果表明:n-SiO2的加入能明显提高尼龙涂层的耐磨性,降低摩擦因数,疲劳磨损、粘附磨损及犁切现象明显减轻;当n-SiO2含量为1.5%(质量分数)时,复合涂层摩擦磨损性能最佳,试验条件下磨损量降低近4倍,摩擦因数降低23%,跑合期降低44%,复合涂层与GCr15钢环对磨时的磨损机制主要为疲劳磨损和轻微的粘附磨损。     

火焰喷涂PA1010/n-SiO2复合涂层干摩擦磨损性能

利用火焰喷涂法制备PA1010/n-SiO2复合涂层,并采用均匀试验设计方法研究涂层在干摩擦条件下同GCr15 钢环配副时的摩擦学性能;利用SPSS 12.0统计软件对试验结果进行回归分析, 建立涂层摩擦系数和磨损质量损失同pv值 (摩擦载荷与摩擦速度的乘积)相关性的数学模型;利用示差扫描量热仪(Differential scanning calorimetry, DSC)和扫描电子显微镜(Scanning electron microscope, SEM)对复合涂层的热性能和磨损表面形貌进行分析。结果表明,n-SiO2的加入能明显提高涂层的结晶性能、耐磨性能。当n-SiO2含量为1.5%时,复合涂层摩擦磨损性能最佳,在试验条件下磨损质量损失降低近4倍,摩擦因数降低23％,跑合期缩短44％,复合涂层与GCr15钢环对磨时的磨损机理主要为疲劳磨损和轻微的粘附 磨损。     

Two-body abrasion of some polymers against 6–50 μm SiC abrasives

Single- and multiple-pass two-body abrasion tests were run on Nylon $\text{6}\text{6}\text{+ 20\%}$ polytetrafluoroethylene (PTFE) and polycarbonate + 10% PTFE sliding dry against 6–50 μm SiC abrasives. A functional relationship was developed between the single-pass wear rate and the abrasive particle size for abrasive particle sizes less than or equal to 10.4 μm. The single-pass abrasive wear rate was 20–40 times greater than the multiple-pass wear rate for each material when it was slid against abrasive grains with a mean size not exceeding 10.4 μm. This was due to the formation of loose polymer fibril wear debris in single-pass sliding and of transferred plateaux of polymer in multiple-pass sliding. The rate of increase in wear with particle size was about 20 times greater for single-pass sliding than for multiple-pass sliding. Above a mean abrasive particle size of 10.4 μm the type of mechanism in both single-pass and multiple-pass sliding was that of ploughing.     

A study on the formation of wear debris during abrasion

A set of five material specimens have been tested on five abrasives, some of which are harder, some softer than the materials, using the dynamic abrasive wear tester. Characteristics of selected wear debris have been observed by sem and wear debris of 9Cr2Mo steel analysed by Mossbauer spectroscopy. The test results show three wear mechanisms operating during abrasion: microcutting, plougging deformation and brittle fragmentation. Different abrasives formed different constituents of wear debris due to dissimilar wear conditions. Softer abrasive tended to form more ploughing debris, although some typical microcutting chips were produced. Crushing strength of abrasive may be an important factor in addition to hardness of abrasive. The microstructure of 9Cr2Mo steel wear debris has been changed by abrasion heat; this temperature could be estimated by Mossbauer spectroscopy.     

钢背衬碳纤维织物/环氧复合材料干摩擦特性研究

研究了钢背衬碳纤维织物/环氧复合材料在环-环端面干摩擦状态下的摩擦学特性,考察了MoS2与石墨粉及其配比、衬层厚度、法向载荷对衬层干摩擦性能的影响,用扫描电子显微镜对衬层的磨损表面及对偶件45^#钢环表面进行了观察与分析。结果表明：厚度为1.5mm的试环衬层在摩擦过程中主要表现出粘结磨损特性,而含20%（质量分数）MoS2粉的0.6mm衬层表现出疲劳磨损与磨粒磨损特性。摩擦因数-时间特性曲线表明MoS2粉在降低衬层摩擦因数的同时能够抑制环氧树脂向对偶钢环表面的粘结;石墨对衬层的减摩效果优于MoS2粉,但摩擦温升引起树脂向偶件表面转移增多使得减摩效果大大降低;质量分数为33%的MoS2与石墨粉衬层表现出最佳的摩擦学性能,衬层摩擦因数具有随载荷先减小后上升的趋势。     

Ductility and the abrasive wear of an ultrahigh strength steel

Ploughing of material to either side of the grooves made by abrasive particles and single indenters was observed for both abrasive wear and single point cutting. The degree of ploughing decreases as the hardness of the material being tested increases. It is possible to incorporate ploughing into the usual equation for the volume abrasive wear rate by introducing a term 1 ? f, where f is the fraction of a wear groove ploughed to either side of the abrasive particle but not removed from the surface. The equation becomes volume wear rate $\text{≈}\text{L(1?f}\text{H}{}_{\mathrm{s}}$ where L is the applied load and H_s is the surface hardness. Although it is possible to relate 1 ? f to hardness through single point scratching experiments, there is evidence that 1 ? f could depend primarily on ductility and not on hardness. As an initial step in exploring the dependence of this ploughing term on the mechanical properties of the abraded material, a simple model of the abrasive wear process is proposed. This model is evaluated in terms of the abrasive wear and tensile properties of a low alloy steel heat treated to hardnesses ranging from 496 to 680 HV.     

Analysis of the abrasive wear mechanism by successive observations of wear processes in a scanning electron microscope

Single-point scratch tests, using a semispherical pin made of hardened steel, on the flat surfaces of brass (60Cu-40Zn) and S45C (0.45C steel) and SUS304 (18Cr-8Ni austenitic stainless steel) steels were carried out under dry and lubricated conditions in a scanning electron microscope. Successive observations in the scanning electron microscope show that the abrasive wear mechanism can be classified into the following four types: cutting, flaking, wedge formation and ploughing. The transitions between the different types of abrasive wear occurred at critical degrees of penetration which are strongly dependent on the conditions of lubrication. The ratio of the wear volume to the groove volume was highly dependent on the four types of wear.     

石墨烯/MoS2复合涂层多环境下的摩擦学性能

以MoS2作为润滑剂,以石墨烯(GE)作为润滑添加剂,采用喷涂法在GCr15钢样片表面制备不同含量的GE/MoS2复合涂层.利用HSR-2M型高速往复式摩擦磨损试验机测试涂层在干摩擦及海水环境中的摩擦磨损性能,并分析了磨痕形貌及磨损机制.结果表明:添加适量石墨烯可明显改善MoS2涂层的摩擦磨损性能,且海水环境中涂层的摩...     

Fretting fatigue of zinc coated low carbon steel EN H320 M

The object of the present study was to investigate the influence of zinc coatings on steel sheets during fretting fatigue and fatigue tests. The influence of the fatigue stress range, normal pressure and amplitude of slip, on the fracture life was studied for both coated and uncoated EN H320 M steel. The wear produced by fretting was measured and compared with the fracture life evolution for different values of slip amplitude. The wear scars and the fracture surfaces were examined by scanning electron microscopy to identify the degradation mechanism. Although zinc films do not influence the fatigue life of the tested steel, when fretting is superposed on to a fatigue stress the coating markedly improves the fracture life.     

Study of abrasive wear phenomena in dry and slurry 3-body conditions

Machinery and equipment used in abrasive environments, such as the mining industry, suffer from severe wear. In order to understand wear and to prolong the life time of the machinery, it is important to understand how materials respond to wear depending on the environmental and tribological conditions imposed.This paper exposes a comparative study between the influence of two abrasive environments (dry and slurry) on hard particle coatings and steels. To study this, the 3-body wear behaviour was evaluated in a dry environment using a continuous abrasion test (CAT) and in a slurry environment using a slurry steel wheel abrasion test (SSWAT) method. Both tests are capable of experimentally modelling the high stress wear at 45 N and 216 N, using quartz sand as an abrasive. The tests were performed on two types of coatings processed by sintering and hardfacing and martensitic steel was used as a reference. The wear was indicated as volume loss by measuring the samples before and after the tests. Furthermore, the specific wear energy was calculated in order to have a fundamental understanding about the material's response to wear. A correlation between the wear rate and the particle brakeage index (PBI) was done for the dry conditions using different loads, in order to explain the interdependence between the two parameters and the change in the wear mechanism between the two loads. The influence of load on the wear of the materials showed different wear mechanisms on coatings compared to the steel in the same environmental conditions. However, a change in wear mechanism at different load levels was observed, which might be directly dependent on the change of the particle's motion from sliding to rolling combined with the change in their shape and size. The results showed that the need to study the influence of different abrasive conditions on the material wear is crucial in order to improve the lifetime and the cost efficiency of the machinery used in such environments. The hard-particle coatings showed comparatively low wear rates promising a great potential in improving the lifetime of industrial equipments in different environments.     

Influence of CrC addition in Ni-Cr-Si-B flame sprayed coatings on microstructure, microhardness and wear behaviour

In the present paper the influence of the addition of chromium carbide (CrC) particles on the microstructure, microhardness and abrasive wear behaviour of flame sprayed Ni-Cr-Si-B coatings deposited on low carbon steel substrate has been reported. Wear behaviour of the coatings was evaluated with a pin-on-block wear system against SiC abrasive medium (120 & 600 grades) over a range of normal load (5–20 N). It was observed that the wear behaviour is governed by the material related parameters (microstructure, microhardness of coating) and test parameters (abrasive grit size and normal load). The addition of CrC reduces the wear rate three to eightfold. Wear resistance was greater against coarse abrasives at high loads than against fine abrasives. Heat treatment of both unmodified (1004) and modified powder (1004-10%CrC, 1004-20%CrC) coatings deteriorated the abrasive wear resistance. SEM study of wear surfaces showed that wear of the coatings largely takes place by groove formation, plowing and scoring. Electron probe micro analysis (EPMA) of the coating was carried out for composition and phase analysis.     

氧化锌晶须填充尼龙1010复合材料的摩擦磨损性能

采用模具挤压成型的方法制备了氧化锌晶须填充尼龙1010复合材料,使用纳米力学测试系统测试了不同含量氧化锌晶须复合材料的硬度和弹性模量,在UMT试验机上考察了复合材料的摩擦磨损性能,然后对磨损表面进行了SEM观察。结果表明：复合材料的硬度和弹性模量随氧化锌晶须含量的增加而增大;ZnOw在保持尼龙1010摩擦性能的同时,可使其耐磨性能提高60％左右。纯尼龙的主要磨损机制为粘着磨损和熔融,填充ZnOw后复合材料的磨损机制转变为疲劳剥层。     

Effect of solid lubricant and fibrous reinforcement on the abrasive wear of polyamides

Short glass fibre‐reinforced polyamide 6 and polyamide 11 (PA 6 and PA 11) with and without a solid lubricant of polytetrafluoroethylene and metal powders (e.g., bronze) and copper as fillers were formulated and characterised for their compositional and mechanical properties. A tribological evaluation of these composites' abrasive wear was carried out by abrading a polymer pin against 80 grade (175 um) silicon carbide (SiC) paper under single‐pass conditions at various loads. It was observed that the fibre reinforcement reduced the abrasive wear resistance of virgin polymers. A combination of fibre and particulate fillers was further detrimental in this respect. Efforts were made to correlate the wear performance with the ductility factor, fracture toughness, and fracture energy in the case of PA 6 and its composites.     

表面具有焊层的45~#钢冲击磨损的实验研究

使用杠杆原理式冲击磨损实验台及表面形貌仪等研究冲击载荷作用下表面具有不锈钢焊层的45#钢的表面损伤行为。实验工况分干接触及2种不同黏度的润滑油润滑3种接触方式,研究在不同冲击次数条件下,材料表面的损伤情况,并探讨不同黏度润滑油对冲击磨损机制的影响。结果表明:不锈钢焊层对45#钢基体起到了良好的保护作用,润滑油的存在会在一定程度上抑制冲击所造成的塑性变形,使冲击凹坑呈现出与干接触时不同的表面形貌;随冲击次数的不同,材料的损伤机制主要是黏着磨损、疲劳破碎及疲劳剥落;在材料损伤的各个阶段均伴有塑性变形的出现。     

羟基硅酸镁粉体添加剂含量对金属表面自修复膜生成的影响及机制

采用羟基硅酸镁粉体作为润滑油添加剂,在MMU-5G材料端面摩擦磨损试验机上,研究了不同添加剂含量对45#钢/45#钢摩擦副磨损表面自修复膜生成的影响及其机制,借助SEM及EDX测试分析摩擦副的表面形貌及表面成分组成。结果表明,自修复添加剂的含量对羟基硅酸镁粉体添加剂在磨损表面形成自修复膜影响显著。在添加剂质量分数为2%,3%和5%的工况条件下,试样磨损表面有自修复膜生成。添加剂质量分数为2%时,易于短时间内达到磨损-自修复动态平衡,自修复效果最为理想。自修复膜的生成过程包含磨粒磨损和摩擦化学反应2个阶段。自修复膜的生成使得试样摩擦磨损表面平整光滑,可以有效降低金属磨损。     

热喷涂MoS2/PA(聚酰胺)复合涂层的摩擦学性能及磨损机理研究

利用热喷涂技术在45钢上制备了MoS2／PA(聚酰胺)复合涂层，考察了不同填料含量复合涂层的摩擦磨损性能，采用SEM分析涂层及对偶磨损表面形貌，并探讨了填料对复合涂层摩擦磨损性能的影响机制。结果表明：填料含量大于39／6时，虽然摩擦因数较小，但磨损率很大，且大于纯PA涂层的磨损率；当填料含量小于3％时，涂层摩擦学性能有所提高。     

Structure and wear resistance of electron-beam nitrous coatings

The paper deals with the study of the tribological properties of nitrogen-containing austenite coatings deposited by electron-beam facing during abrasive wear and the sliding friction of a VK6 hard alloy indentor. The abrasive wear resistance of the nitrous coatings deposited by the electron-beam facing of steel 60Kh24AG16 powder in quartz sand is lower than that of the steel 65G coatings after hardening; it increases with increasing mass share of the filler. At contents of nitrided ferrovanadium of 10?C30 wt % the abrasive wear rate increases by 30?C50%, respectively. It is found that under a certain load applied to the VK6 ball indentor the friction coefficient and the shear resistance of the surface layer diminish. It is shown that under heavy specific loads applied to the ball indentor the nitrous coating faced from steel 60Kh24AG16 powder and composite nitrous coatings have wear resistance exceeding that of steels 110G13 and Kh18N10 by more than two and seven times, respectively. Based on the results of structural studies an explanation of the observed behavior of the nitrous coatings is proposed.     

油管涂层的摩擦学性能实验研究

为了治理有杆泵井的管杆偏磨问题,在油管上喷涂了一层耐磨防腐涂层,并对比研究了抽油杆和油田常用的油管摩擦副及喷涂耐磨涂层后的油管摩擦副的摩擦磨损性能。结果表明:与45#钢对磨时,N80的耐磨性要比J55好;当45#钢与J55涂层油管对磨时,J55涂层油管的耐磨性比J55油管提高了5倍,并且配对的45#钢的磨损量也降低了1/2;因此45#钢与J55油管涂层配合使用时防偏磨效果十分理想。     

Surface Morphology Studies in Polymer-Graphite/Epoxy Sliding

Ultrahigh-molecular-weight polyethylene (UHMWPE) and polycarbonate pins were slid dry against continuous graphite fiber/epoxy plates in reciprocating multiple-pass wear tests for different values of virgin surface roughness, fiber orientation, and load. Scanning electron photomicrographs of the polymer wear surfaces were combined with three-dimensional graphs of wear rate versus virgin surface roughness and fiber orientation. The types of surface damage observed for UHMWPE at both an 8.9- and 35.6-N load were mild plastic deformation, fatigue of loose particles, and light abrasive cutting. The types of surface damage observed for polycarbonate at either load were massive abrasive plowing and plastic flow of material. The wear debris of UHMWPE consisted of rolled, cut, or extruded particles; for polycarbonate, clumps of transferred plateaus of polymer. The unit pressure times velocity (PV) limit for polycarbonate was reached when samples were slid against the most abrasive counterface transverse to the graphite fibers.