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1.
The aim of the current study was to investigate erosive and impact/abrasive wear behaviour of TiC–NiMo and Cr3C2–Ni reinforced NiCrBSi hardfacings at temperatures up to 700 °C.Coatings were produced using plasma transferred arc cladding process. It was shown that the high temperature wear behaviour of TiC–NiMo and Cr3C2–Ni NiCrBSi hardfacings is influenced by oxidation. The formation of mechanical mixed layers and oxide films was observed for both investigated coatings. TiC–NiMo and Cr3C2–Ni reinforced hardfacings show high wear resistance at all testing temperatures for both impact/abrasion and erosion conditions.  相似文献   

2.
《Wear》2006,260(4-5):450-457
Intermetallic Mo(Si,Al)2, Mo(Si,Al)2/Al2O3, Mo(Si,Al)2/SiC and Mo(Si,Al)2/ZrO2 composites produced by spark plasma sintering of mechanically alloyed powders were tested on a block-on-cylinder apparatus, sliding against an AA6063 alloy cylinder at elevated temperature. Abrasion, micro-fracture and surface tribochemical reactions were found to be the operative wear mechanisms, producing severe wear in the investigated alloys. Abrasive wear by pull-out of Al2O3 and micro-fracture of Mo(Si,Al)2 particles promotes severe wear in the Mo(Si,Al)2/Al2O3 composite. In the Mo(Si,Al)2/SiC composites, hard SiC inclusions suppressed the abrasive wear, but a tribochemical reaction was found to be the dominant wear mechanism. A combination of abrasion by pull-out of Al2O3 particles and a tribochemical reaction was revealed to be the main wear mechanism in the Mo(Si,Al)2/ZrO2 materials. The brittleness index B = H/K1C was applicable for prediction of the relative wear resistance. In agreement with the suggested model, the lowest wear rate, corresponding to B = 5.5–6.5 μm−1/2, was found in the Mo(Si,Al)2/30 vol.% SiC and Mo(Si,Al)2/30 vol.% ZrO2 composites.  相似文献   

3.
Slurry erosion performance of detonation gun (D-gun) spray ceramic coatings (Al2O3 and Al2O3–13TiO2) on CF8M steel has been investigated. Slurry collected from an actual hydro power plant was used as the abrasive media in a high speed erosion test rig. Attempt has been made to study the effect of concentration (ppm), average particle size and rotational speed on the slurry erosion behaviour of these ceramic-coated steels under different experimental conditions. The analysis of eroded samples was done using SEM, XRD and stylus profilometry. The slurry erosion performance of the D-gun spray Al2O3–13TiO2-coated steel has been found to be superior to that of Al2O3-coated steel. Both the coatings showed brittle fracture mechanism of material removal during the slurry erosion exposure.  相似文献   

4.
Three multilayer-coated carbides [two trigon-shaped inserts: Ti(C,N)/TiC/Al2O3 (T1), Ti(C,N)/ Al2O3/TiN (T2) and one 80°-rhomboid shaped insert: TiC/Al2O3/TiN (T3)] were used to machine a martensitic stainless steel at various combinations of cutting speed and feed rate without coolant to assess their wear performance. Significant nose wear and chipping/fracture of the cutting edge were the predominant failure modes affecting tool performance at higher speed conditions. Plucking of tool materials was the main rake face wear phenomenon observed on T1 grade insert with alumina as the top-layer coating when machining at the lower speed conditions. Attrition and plastic flow were the main wear mechanisms observed on the ceramic coating layers, with dissolution-diffusion being the probable wear mechanism of the tool grades where tungsten carbide substrate had direct contact with the flowing chip. The fitted statistical wear models revealed T3 grade insert with 80°-rhomboid shape as having the highest speed-feed capability, resulting in the highest material removal rate relative to T1 and T2 grade inserts with trigon shapes.  相似文献   

5.
(TiB2–TiC)–Ni/TiAl/Ti functionally gradient materials were prepared by field-activated pressure-assisted synthesis processes. (TiB2–TiC)–Ni composite ceramic, the top layer of the functional gradient materials, was prepared in situ by the combustion synthesis process using Ti and B4C powders as raw materials. Scanning electron microscope (SEM) images of the ceramic layer revealed that the TiB2 and TiC particles in the composite were fine and homogeneously dispersed in the Ni matrix. The friction and wear properties of the (TiB2–TiC)–Ni ceramic were evaluated by sliding against a GCr15 disk at temperatures from ambient up to 400 °C. The experimental results showed that the friction coefficient of the (TiB2–TiC)–Ni ceramic decreased with the increasing testing temperature, load, and sliding speed. However, the loss rate decreased at higher temperature and increased at higher load and higher sliding speed. The wear mechanisms of (TiB2–TiC)–Ni ceramic mainly depend upon thermal oxidation at higher temperature, load, and sliding speed. The worn topography and phase component of the worn surfaces were analyzed using SEM, energy dispersive spectroscopy, and X-ray diffraction. The oxide films of Fe2O3, TiO2, and B2O3 formed during the friction process play an important role in lubrication, which results in a smaller friction coefficient.  相似文献   

6.
Xian Jia  Xiaomei Ling 《Wear》2005,258(9):1342-1347
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.  相似文献   

7.
The influence of the strengthening phases on the tribological characteristics (wear intensity, specific work of wear, coefficient of friction) and the wear mechanisms in two-body abrasion tests with abrasives of different hardnesses (corundum Al2O3, ~2000 HV and silicon carbide SiC, ~3000 HV) has been investigated for PG-SR2 (Cr23C6, 1000–1150 HV), PG-10N-01 (Cr7C3, 1650–1800 HV; CrB, 1950–2400 HV), and 75% PG-SR2 + 25% TiC (TiC, 2500–2900 HV; (Cr,Ni)23(C,B)6 and (Ti,Cr)(C,B), ~2000 HV) coatings. The dominant role of the strengthening phases (compared with the role of the metal matrix) in the abrasive wear resistance of laser-clad NiCrBSi coatings has been estimated. Different wear mechanisms have been identified and, accordingly, different levels of coatings wear resistance have been achieved depending on the ratio between the hardness of the strengthening phases (carbides, borides, carboborides) and abrasive particles.  相似文献   

8.
The tribological characteristics of low-pressure plasma-sprayed (LPPS) Al2O3 coating sliding against alumina ball have been investigated from room temperature to 800 °C. These friction and wear data have been compared quantitatively with those of bulk sintered alumina to obtain a better understanding of wear mechanisms at elevated temperatures. The friction and wear of Al2O3 coating show a strong dependence on temperature, changing from a mild to a severe wear regime with the increase of temperature. The coefficient of friction at room temperature is approximately 0.17 to 0.42, depending on applied load. The tribochemical reaction between the coating surface and water vapor in the environment and the presence of the hydroxide film on the Al2O3 coating reduce the friction and wear at room temperature as contrasted to those of bulk sintered alumina. At intermediate temperatures, from 400 to 600 °C, the friction and wear behavior of Al2O3 coating depends on the inter-granular fracture and pull-out of Al2O3 grains. At above 700 °C, formation and deformation of fine grain layer, and abrasive wear in the form of removal of fine alumina grains further facilitate the friction and wear process of Al2O3 coating.  相似文献   

9.
新型陶瓷喷砂嘴的制备及其应用   总被引:1,自引:0,他引:1  
分析了喷砂嘴材料和结构的发展情况,采用热压烧结工艺制备出了B4C/(W,Ti)C新型陶瓷喷砂嘴,结果表明随(W,Ti)C含量的增加,陶瓷喷嘴材料的致密度显著增加,晶粒显著细化,保温时间大大缩短,抗弯强度和断裂韧性大大提高;以SiC为冲蚀磨料进行的喷砂冲蚀试验证明了新型陶瓷喷砂嘴的抗冲蚀磨损能力远高于金属、硬质合金和其它陶瓷喷嘴。  相似文献   

10.
The two-phase Al2O3–TiC ceramic (AlTiC) has many applications. One of the most common uses of AlTiC is for data recording heads where it is used as a bearing surface to support the magnetic sensing elements. This is one of the examples where the ceramic can be used in MEMS. Using Linear Tape Open (LTO) drive and metal particle (MP) tape media as the experimental platform; the wear of the AlTiC at very low loads and for very smooth surfaces has been studied.X-ray photoelectron spectroscopy (XPS), Auger electron Spectroscopy (AES) and Atomic Force Microscopy (AFM) were employed to analyse the AlTiC surface changes during wear at a variety of environmental conditions. Under all experimental conditions, the results showed the TiC phase of AlTiC to have been oxidized to form a surface layer. This gave rise to classical oxidational wear of that phase; with the delamination of the TiO2 to form pullouts on the AlTiC surface and subsequent three-body abrasive wear particles were produced. The rate of oxidation of the TiC and hence the rate of production of the three-body wear particles increases with atmospheric water vapour content. In the experimental system chosen for this investigation, this results in an increase in differential wear, and hence pole tip recession of the magnetic metal poles of the recording heads. Pole tip recession was shown to correlate with increase in oxidation rate and also increase with atmospheric water vapour content.The wear of the Al2O3 phase was probably due to micro-adhesive wear with a wear rate much lower than that of the TiC phase.  相似文献   

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