【作者】 肖磊；

【导师】 邹家生；

【作者基本信息】 江苏科技大学 ， 材料加工工程， 2011， 硕士

【摘要】 金属粉末注射成型(MIM)因其制品具有高质量、高精度等优点成为近年来粉末冶金工业研究的热点。铜及铜基合金因具有导热率高、塑性好、延展率大、常温下与氧亲和力小、耐腐蚀性强等一系列优点,在现代导电导热材料、摩擦材料等方面占据了重要的地位。本文主要利用粉末注射成型技术制备铜基摩擦材料,优化了材料制备过程中的各工艺参数。在基本工艺研究的基础上,借助扫描电镜、X射线衍射仪及摩擦磨损试验机等仪器设备,对铜基粉末冶金摩擦材料的表面组织形貌、密度及互动摩擦磨损特性进行了较为系统的研究与分析。最后给出了其摩擦磨损性能。经工艺试验研究,注射成形最佳喂料工艺为:粉末装载量54%;粘结剂60%PW+25%LDPE+10%SA;混炼温度150℃;混炼时间2h。采用正交试验法系统研究了注射压力、注射温度、注射速度及其交互作用对注射预成形坯质量的影响,评价了各参数对成形坯质量的影响,获得了注射成形的优化注射工艺参数。最佳注射参数为:注射温度155℃,注射压力110 MPa,注射速度40m?s-1,锁模力90 MPa,保温时间10s。最佳脱脂工艺参数为:40℃脱脂6h。在560℃以下烧结时,升温速度应当控制在2℃·min-1以下;升温结束后,可采用快速降温的方式冷却。随着烧结温度的升高,试样的致密度逐渐提高;延长高温阶段的保温时间至10min有利于孔隙的消除,从而增加试样的致密度。摩擦磨损试验表明:采用粉末注射成形工艺制取的铜基摩擦材料,随着石墨含量的增加,材料的孔隙率增加,造成基体材料的密度及硬度均呈下降趋势。当石墨含量小于10%时,随着石墨含量的增加,减摩材料及对偶件的磨损率逐渐降低;当石墨含量处于10%～15%时,磨损率较小,摩擦系数能够稳定维持在较低水平,从而减少减摩材料的消耗,能够形成保护膜降低对偶件的磨损,保护对偶件;当石墨含量大于15%时,减摩材料的磨损率上升,摩擦系数增大。当石墨含量在10%～15%之间时,减摩材料既能获得较好的密度、硬度,又能充分发挥减摩效果,保护对偶件。更多还原

【Abstract】 Metal Injection Molding (MIM) for its products with high quality, high-precision powder metallurgy industry and so become a hot research in recent years. For copper and copper alloy with high heat conductivity, good plasticity, extension rate, small oxygen affinity at room-temperature, high corrosion resistance and a series of advantages, in the modern thermal conductivity, friction materials, such as to occupy an important position.This article was prepared by Metal Injection Molding to produce friction material, optimize the parameters of material preparation process. On the basic of technology, the microstructure,density , friction and wear characteristics of the copper-based powder metallurgy friction material treated by surface transformation were systematically studied and analysised by means of scanning electron microscopy(SEM), X-ray diffraction (XRD),and wear tester and other equipment. Finally, given the comprehensive performance of friction and wear by comparative studies.Based technology test showed that the best injection molding feedstock preparation process: powder loading: 54%, adhesive formulations: 60% PW +25% LDPE +10% SA, mixing temperature: 150℃, mixing time: 2h. The injection pressure, injection temperature, injection speed and their interaction on the quality of preform injection were studied by orthogonal system to evaluate the various parameters on the forming blank quality, access the effection of injection molding process parameters optimization on injection .Optimal injection parameters were: injection temperature 155℃, injecting pressure of 110MPa, the injection speed 40 m?s-1 clamping force of 90MPa, holding time of 10s. The best skim process parameters were 40℃for degreasing 6h. The following sintering at 560℃, the heating rate should be controlled under the 2℃·min-1; rapid cooling can be a way to cool after the heating process. When Sintering, with the increasing of the temperature, the density of the sample gradually increase; extend the high temperature stage’s holding time conducive to 10min to eliminate porosity, thereby increasing the density of the sample.Friction and wear tests show that with the graphite content increases the metal powder injection molding preparation friction material increases the porosity, causing the density of the matrix material and hardness decreased. When the graphite content of less than 10%, with the increase of graphite content, reducing friction material and the wear rate of the coupled parts decreased. When the graphite content is 10% to 15%, the wear rate low and the friction coefficient can be stable at low levels, thereby reducing the friction-reducing material consumption to form a protective film reduces wear on the coupled parts, protection of the coupled parts; When the graphite content is more than 15%, the wear rate of friction increase, the friction coefficient increases. When the graphite content from 10% to 15% both anti-friction material to obtain better density, hardness, friction-reducing effect and can give full play to the protection of dual pieces.更多还原