共查询到17条相似文献,搜索用时 156 毫秒
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采用NiCr合金钎料,通过Ar气保护和真空钎焊的方法制备了钎焊金刚石耐磨性试件,并研究了钎焊气氛对金刚石磨耗特性的影响。结果表明:在试验条件完全相同的情况下,不同的钎焊气氛导致金刚石磨耗特性不同,即经真空钎焊金刚石的磨耗特性表现为破碎方式,而经Ar气保护炉中钎焊金刚石的磨耗特性初始表现为磨耗平台方式,其后随着磨耗平台面积的增大,金刚石出现破碎。最后采用Ar气保护和真空钎焊方式制作了金刚石套料钻并进行了钻削试验,由于磨耗特性的不同,Ar气保护炉中钎焊套料钻较真空钎焊套料钻具有更长的使用寿命。 相似文献
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钎焊气氛对金刚石钎焊性能的影响 总被引:2,自引:0,他引:2
主要利用Cu-10Sn-5Ti钎料粉末,在空气、Ar气保护和真空气氛下分别对金刚石进行钎焊试验,通过扫描电子显微镜观测金刚石钎焊形貌、X射线衍射仪分析界面生成物成分、激光拉曼光谱仪检测金刚石石墨化程度、磨损试验分析金刚石破损形式等手段,考察研究不同钎焊气氛对金刚石钎焊性能的影响。试验结果表明,在空气中钎焊时,钎料粉末出现了一定的氧化,生成的氧化膜阻碍了界面反应的充分进行,对钎焊性能有一定的影响,金刚石也出现了较严重的热损伤,磨削过程中出现了少数部分颗粒脱落的情况;而在Ar气保护和真空钎焊时,钎料充分润湿和铺展,实现了对金刚石的高强度把持,金刚石石墨化程度很小,金刚石主要经历了完整、小块破碎、大块破损、磨平等正常磨损形式,金刚石利用率高。 相似文献
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为研究高温钎焊金刚石工具时基体所受的热损伤对同种材料不同热处理状态下的工具基体进行分析与检测。基体材料选择45钢制作试样,对原始试样、真空炉中干烧至钎焊温度的试样以及与金刚石钎焊后试样的显微结构和显微硬度进行检测与对比分析;对原始试件和真空干烧过的试件进行拉伸性能试验,并用扫描电镜(SEM)对断口形貌进行观察。结果表明:45钢基体经高温真空干烧和钎焊后,晶粒粗大,致使强度、硬度、塑性等力学性能大幅下降,基体材料出现严重的热损伤。研究成果可为钎焊金刚石工具基体材料的选择和钎焊工艺的制定提供试验和理论依据。 相似文献
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基于脉冲激光加工时的低能量输入和较小的热影响优势,将其应用到金刚石磨粒的钎焊过程中,以实现多层金刚石磨粒的逐层钎焊成形。通过单道及单层脉冲激光钎焊试验,研究了工艺参数对钎焊成形及对金刚石损伤的影响规律,并优选出较好的工艺参数进行了多层钎焊试验。研究结果表明:在脉冲激光钎焊成形过程中,工艺参数的变化主要通过改变峰值功率密度和线能量密度来影响钎焊成形和金刚石损伤形态。输入的能量密度不足时,钎焊道及钎焊层易出现熔融球、金刚石聚集、熔合不充分、不连续及不平整等现象;输入的能量密度过大时,易出现金刚石损伤、粉末材料及金刚石流失逃逸等现象。当线能量密度为14~25 J/mm2、峰值功率密度在5×105~1.5×106 W/cm2时,可得到平整性良好和金刚石磨粒形态良好的钎焊形貌,且在此参数范围内优选的参数条件下实现了多层结构的逐层钎焊成形,得到了较好的表面成形形态及较低的金刚石损伤形态。多层钎焊试块弯曲试验结果表明,钎焊层与基体之间具有较好的结合强度,未出现钎焊层剥离现象。 相似文献
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为解决传统树脂砂轮片干式磨抛高强度钢存在的磨抛效率低、火花大、粉尘多、安全性低等问题,分析了利用钎焊金刚石技术的优势制备新型磨抛盘的可行性,并提出了解决对策。结合新型金刚石磨料排布工艺,利用Ni-Cr合金焊料,真空钎焊制备了钎焊金刚石磨抛盘。对AH36船用高强度钢进行了干式磨抛对比试验。试验表明:与传统树脂砂轮片相比,钎焊金刚石磨抛盘磨削效率提高40%左右,磨削寿命是前者的12倍以上;磨屑平均体型较大且种类多,无熔融状磨屑存在,磨粒表面基本无磨屑粘附,证明了新型磨抛盘干式磨削时可有效控制磨削温度。 相似文献
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基于模压成形和真空固相烧结工艺,选用Cu-10Sn结合剂、经氧化预处理的TiH2钎焊造孔剂、MBD8金刚石磨粒,制备出磨粒把持力大、孔隙分布均匀的多孔钎焊金刚石砂轮(PBDGW)。开展PBDGW与多层钎焊金刚石砂轮(MBDGW)的SiC陶瓷磨削对比试验,从磨削力、工件表面粗糙度和表面/亚表面形貌等方面分析砂轮的磨削性能。试验结果表明:与MBDGW相比,PBDGW磨削SiC陶瓷的切向力下降了8.4%~23.6%、法向力下降了10.2%~38.6%,磨削加工表面粗糙度平均降幅为10.4%;工件表面完整性较好,表面/亚表面的脆性断裂、微观裂纹等缺陷较少。 相似文献
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以Ni-Cr合金为钎料,分别用真空加热和高频感应加热两种方式进行了金刚石磨粒与0Cr18Ni9不锈钢基体的钎焊,制作了基体外径为3 mm的薄壁小孔钻头。进行了半钢化玻璃钻削试验,用扫描电子显微镜观察钻削试验前后钻头的微观形貌。结果表明:两种钎焊工艺皆实现了金刚石磨粒的高强度连接;加热源不同及金刚石磨料出露高度差异性是影响钻头磨损方式的主要因素;为确保钻头的寿命和高效,磨粒出露高度应控制在其自身高度的50%-60%之间。 相似文献
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将热丝化学气相沉积(HFCVD)处理的金刚石作为磨料感应钎焊制作金刚石工具。HFCVD处理试验中,混合气为H2和CH4(体积流量比为100∶1.5),炉内压力为2.0kPa,700℃下处理45min后,在金刚石表面沉积了一层非晶碳膜。感应钎焊HFCVD处理的金刚石显示,出露部分的金刚石棱边能保持良好的锋利性;浸没在钎料层下面的金刚石表面形成了有均匀孔隙且形状不规则的铬碳化合物,液态钎料充填这些化合物孔隙之间,能够增强钎料对金刚石的把持强度。3种金刚石磨料感应钎焊制作的金刚石磨盘的高效重负荷石材磨削试验显示,HFCVD处理的金刚石的整体破碎率和脱落率最低。 相似文献
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《Wear》2007,262(5-6):693-698
There are three types of conditioners discussed, they were manufactured as follows: (a) bonded by electroplating nickel (ED); (b) brazing Ni–Cr alloy (BD); and (c) diamond-like carbon (DLC) film deposition on a brazed conditioner (BDD). After a wear-corrosion test, the brazing process shows no diamond fall-out when compared with the electroplating process. The denser distribution of diamond grits causes a lower coefficient of friction and a lower weight loss of counterpart, and this in turn causes the ring rotating but less ploughing action during the wear-corrosion test. A good clearance between each diamond grits benefits the penetration against counterpart, and indeed scrapes (i.e. conditions) more efficiently. DLC film deposited on the conditioner surface of brazed Ni–Cr alloy conditioner BDD exhibits the best overall performance in terms of a higher removal rate, a lower wear loss and a better corrosion resistance when compared with conditioners ED and BD. 相似文献
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Ching-Jui Shih Shih-Fu Ou Chia-Hung Yeh Chao-Sung Lin Yung-Ning Pan 《The International Journal of Advanced Manufacturing Technology》2013,68(9-12):2329-2334
Microfabrication was employed in the fabrication of diamond dressers. Diamond-nickel composite was utilized for fabricating columnar cutting tips and compared with those fabricated by the brazing connective approach. In this study, microcolumns with diamond grits embedded in the nickel deposit electroplated on the substrate with guidance of the resist mold can improve the population density of working diamond grits in the diamond dresser. Moreover, the load force is dispersed on the plurality working diamond grits within one column, which in turn increasing in the durability of the dresser. This technique can produce diamond dressers with improved uniformity in both the distribution and protrusion control of microcolumn diamond cutting tips. In addition, the presently developed diamond dressers exhibit an increase in material removal rate by some 15 %, while, at the same time, maintain a relatively low worn rate as compared with the commercially available dressers. This microcolumn (e.g., diamond-nickel composite) is efficient to share the applied load and also extends tool’s life during polishing. 相似文献
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Ni-Cr合金真空钎焊金刚石界面微结构分析 总被引:2,自引:0,他引:2
钎焊单层超硬磨料砂轮极高的结合强度和接近理想的锋利形貌 ,使它在生产应用中显示出传统砂轮无法比拟的优异性能。这种新型超硬磨料砂轮以其卓越的磨削性能必将逐步取代传统单层电镀砂轮。本文在真空炉中用钎焊的方法 ,用Ni Cr合金钎料 ,适当控制钎焊温度、保温时间和冷却速度 ,实现了金刚石与钢基体的高强度连接。并用深腐蚀的方法处理钎焊后的试样 ,用扫描电镜、X 射线能谱仪 ,结合X 射线衍射结构分析 ,对金刚石与钎料界面微区结构进行了分析。结果表明 :在钎焊过程中 ,钎料会在金刚石界面形成富铬层并与金刚石表面的C元素反应生成Cr7C3 和Cr3 C2 ,其中Cr7C3 呈笋状生长 ,Cr3 C2 呈片状生长。Ni Cr合金与金刚石的冶金结合 ,是实现金刚石和钢基体有高结合强度的主要因素。最后通过磨削对比实验确证了金刚石与钎料有较高的结合强度 相似文献
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Bojiang Ma Qingxian Yu 《The International Journal of Advanced Manufacturing Technology》2012,63(5-8):555-560
The ambience in which brazed diamond wheels are fabricated has an important effect on the sharpness of the brazed diamond grits and on the hold of the filler alloy on these grits. In this work, brazed diamond wheels were fabricated using NiCr alloy either in a 0.05-Pa vacuum or in H2/CH4 plasmas at a temperature of 1,020°C for 5 min. The surface of the diamond grits brazed in H2/CH4 plasmas and protruding out of the filler alloy is not graphitized. The layer of carbide formed on the interface between the filler alloy and diamond brazed in H2/CH4 plasmas allows the liquid filler alloy to soak the diamond grits better. This is good for the filler alloy gaining a firm hold on the diamond grits. Diamond grits brazed in H2/CH4 plasmas undergo compressing stress due to the penetration of carbon into the filler alloy. There is a white band, which denotes firm metallurgical bond, between the filler alloy and the substrate of a brazed diamond wheel fabricated in H2/CH4 plasmas or in the 0.05-Pa vacuum, but the bandwidth in the brazed diamond wheel fabricated in H2/CH4 plasmas is almost twice that in the brazed diamond wheel fabricated in the 0.05-Pa vacuum. Grinding tests showed that the percentages of both whole grain fractures and pullouts from the matrix of diamond grits brazed in H2/CH4 plasmas are lower than those of diamond grits brazed in the 0.05-Pa vacuum. 相似文献