采用镍钴锰镀层制造玉雕用金刚石工具

采用镍钴锰镀层制造玉雕用金刚石工具,可以实现镍钴锰合金的共同沉积。由于电镀金刚石钻头的制造是在常温下进行的,金刚石未受高温损失,同时金刚石粘结牢固,钻头制造工艺简单,设备投资少,一次成型,能修复使用。采用镍钴锰镀层制造玉雕用金刚石工具在制造过程中,结合合金材料的特点,利用电镀技术,实现了三元合金元素的共同积淀,增加了玉雕工具的韧性。利用镍钴锰镀层三种合金的金刚磨头,也可以有效降低金刚石具的成本。本文在研究过程中,对金刚石工具的新生产工艺进行了研究。     

直径400mm金刚石锯片的胎体材料研究

研究了直径４００ｍｍ金刚石锯片的胎体材料和制造工艺，获得了具有良好综合力学性能的铁铜基胎体，同时得到适合切割太行红花岗石的直径４００ｍｍ的铁铜基金刚石锯片。     

添加剂对预合金粉末胎体性能及其金刚石工具使用效果的影响

研究了ＴＴ１５预合金粉末及添加适量其他成分后的烧结性能，对金刚石的包镶与粘结性能及其组织结构，确定了该种粉末作为金刚石工具胎体的制造工艺条件，指出以ＴＴ１５合金粉末为基，通过添加适量铜合金或钴，可以得到适用于不同石材的金刚石工具胎体。     

日本三协铝开发铝制渔网用浮标

日本三协铝开发了一种渔网用铝制浮标。历来渔铝网用浮标多用树脂制造，由于树脂浮标劣化造成海洋污染和废弃物处理的问题，日本富山县渔业生产联合会委托三协铝开发铝制浮标以代替树脂浮标。三协铝进行了市场调查，研究了事业化计划。据三协铝推测，每年要替换100万个树脂浮标，今后在     

粉末冶金粘结技术在金刚石产品上应用获显著效果

北京粉末冶金研究所研究的金属与金刚石浸润和粘结技术,使含钛粉末冶金材料对金刚石的粘结抗剪强度达10.57公斤力/毫米z。将该技术应用于金刚石拉丝模和人造金刚石唱针的制造获得成功。以拉丝模为例,可使寿     

金刚石工业用粉末材料的研究与发展

我国人造金刚石及其工具的发展,令世人瞩目。它的发展与粉末冶金息息相关。本文结合作者的研究工作,扼要阐述合成金刚石用的硬质合金顶锤、粉末触媒,制造金刚石工具用的金属胎体粉末在我国金刚石工业中使用现状及发展前景。     

晶体院人工合成金刚石用触媒合金粉末生产线迁建升级完成

正北京中材人工晶体研究院作为国内最早参与研发人造金刚石合成的单位之一,多年来一直致力于金刚石领域的研究和生产。其中,人工合成金刚石用触媒合金粉末以2000年的"水雾化制造金刚石工具胎体合金粉末"项目研究成果为依托,研发出水雾化法制备触媒合金粉末,替代了传统的片状触媒,同时将进口设备国产化替代,为触媒合金粉末乃至金刚石行业的快速发展奠定了良好的基础。     

以含钛粘结材料为模芯的金刚石拉丝模

用含钛粘结材料做模芯制造的拉丝模,模芯对金刚石具有机械卡固和粘结双重作用,克服了传统黄铜模芯因对金刚石仅有机械卡固作用而使金刚石容易出现松动和开裂的缺点,提高了金刚石在模芯中嵌锒的牢固程度,在相同条件下使模具寿命提高2-4倍,获得了较为显著的经济效益。     

用金属模具热压金刚石圆锯片节块试验研究

通过对不同热压工艺与传统热压工艺制造出的试块的密度、硬度、抗弯强度及金刚石最大出刃高度对比及用不同热压工艺制造的锯片锯切混凝土、花岗岩板试验的研究表明:对于本试验胎体材料,用低温、高压热压工艺的金刚石最大出刃高度比用传统热压工艺的高;低温、高压热压工艺制造出来的金刚石锯片的性能不比用传统热压工艺制造出来的锯片的性能差;其烧结温度可降低50～110℃,这将能充分发挥金属材料抗氧化性强,低温强度高的优势,从而使金属材料能应用于制作金刚石制品的热压模具.     

德巴罗伊特大学制成超硬材料

德巴罗伊特大学制成超硬材料德国巴罗伊特大学奥尔佛刚教授领导的研究小组于１９９５年研究出一种氮化碳（Ｃ３Ｎ４）材料，其硬度比金刚石的还高，可用来代替金刚石制造需要超硬的精密零件，另外，这种材料还具有：力学强度大，抗腐蚀性能强，可在很高的温度下使用，并具...     

磨削硬质合金用金属结合剂金刚石砂轮的性能影响因素

硬质合金具有硬度高、强度好、耐腐蚀和耐磨损的特点,采用传统方法难以满足精密及超精密加工的技术要求。文中研究人造金刚石的品种、粒度、浓度和金属结合剂成分等对金刚石砂轮磨削性能的影响,结果表明：在相同浓度下,粗粒度砂轮具有较高的磨削效率,随着磨粒粒度减小,加工表面质量得到改善,但砂轮尖角保形性先提高后减小;结合剂中加入强碳化合物形成元素和控制结合剂中脆硬相含量有助于提高砂轮磨削性能。     

孔隙率对超薄金刚石切割砂轮性能的影响

研究了超薄金刚石切割砂轮中孔隙率对金属结合剂的影响,以及不同压力和温度对金刚石砂轮孔隙率的影响。实验结果表明,压力对砂轮孔隙率的贡献明显高于温度,温度对孔隙率的贡献主要表现在孔隙的形貌上。本实验用数学方法推导了超薄金刚石切割砂轮孔隙率与其抗弯强度的关系,为超薄金刚石切割砂轮的配方和工艺设计提供了数据基础和实践经验。     

铸铁短纤维在金刚石砂轮中的应用

在研究成形、烧结工艺参数对铸铁短纤维烧结体显微组织和性能影响的基础上,研制出新型金刚石磨具—铸铁短纤维结合剂金刚石砂轮。与国内优质青铜结合剂金刚石砂轮相比,该砂轮更适于陶瓷类硬脆材料的高效磨削加工。在磨削发动机Si_3N_4缸套时,磨削效率提高2倍,磨削比提高5倍。     

THE TRIBOLOGICAL ASPECTS OF METAL-BONDED DIAMOND GRINDING WHEELS

Abstract

The field of metal-bonded diamond grinding wheels and saws is described. The production of these tools is an important part of the industrial-diamond industry, yet methods of construction, formulation and use raise practical problems that have not so far received a comprehensive and fundamental appraisal.

A theoretical approach to the subject is adopted in which the perfect wheel is considered in terms of a balanced system of matrix wear vs. the useful life of the diamond point. The discussion emphasizes the close association of grinding with tribology and explains how control of the wear of the metal matrix, together with the correct choice of diamond parameters, plays an important part in the performance of the wheel. It is stressed that lubrication during the grinding operation is the dominant factor in achieving maximum efficiency and economy.

The metal matrix is considered with regard to both its wear characteristics and its diamond-retention properties. Some wear data for common matrices are quoted, and reference is made to the use of fillers to modify matrix properties. The relation of theory to practice is then brought into sharper focus by reviewing methods of manufacture and the influences that lead to the choice of suitable production techniques.     

Structure of a Diamond–Matrix Interface and Durability of a Diamond Tool Fabricated by the Metallization of Diamond with Chromium during Sintering of the WC–Co Briquette with Copper Impregnation

Russian Journal of Non-Ferrous Metals - The structure, as well as the elemental and phase compositions of the diamond–matrix interface of a diamond tool for abrasive wheel dressing,...     

开槽金刚石修整滚轮的研究

开槽金刚石修整滚轮是用于如工蜗杆砂轮的专用成形工具，本文论述了其胎体材料的选择依据，研究了减小其变形、提高其毛坯精度的工艺技术，并在同行业中首次采用了独特的金刚石排布工艺。     

Wear resistance of chromium-containing matrices of diamond drilling tools

The paper examines the wear rate in friction of copper-impregnated samples produced by pressing of VK6 powder with chromium additions. The test is conducted on a cast iron disk in the presence of a wet SiC powder and on a diamond wheel without cooling. It is shown that higher chromium content insignificantly increases the sample wear rate in friction with the cast iron disk. At the same time, the wear rate abruptly decreases for the diamond wheel. The hardness of the samples does not significantly change with increasing chromium content to 6 wt.%.     

稀土夹杂物对D6AC超高强度钢力学性能的影响

本文研究了稀土夹杂物含量对Ｄ６ＡＣ钢强度和塑性的影响，得出了夹杂物的体积百分率与断面收缩率的定量关系式。从夹杂物尺寸和数量方面探讨了对Ｄ６ＡＣ钢韧性的影响。并提出了改善性能的途径。     

Surface treatment techniques for resin composite repair

PURPOSE: To compare bond strengths of fresh resin composites to previously polymerized ("aged") composites following various surface treatments. MATERIALS AND METHODS: Eighty Pertac Hybrid (PH) and an equal number of Silux Plux (SLX) specimens were fabricated and stored for 1 week prior to surface treatment. The specimens were then polished and stored for an additional 24 hours prior to final surface treatment. The surface treatments included use of one of the following: (1) diamond bur (DB), (2) microetcher with 50 microns Al2O3@80 psi pressure (ME), (3) high-pressure air abrasion with 27 microns Al2O3@psi, (KCP), or (4) low-pressure silicate ceramic deposition using 30 microns particles@34 psi (CJ-S) with a microetcher. Half of the samples were treated with a silanating agent. Fresh resin composite (same type as used for the aged specimen) was bonded to the treated surfaces, and specimens were then stored 24 h and thermocycled 300 x at 5 degrees and 55 degrees C prior to testing for shear bond strength. Two-way ANOVA was used to determine significant differences between mean shear bond strengths for both composite materials. RESULTS: Significant differences were found between the groups for both surface treatment and silane use (P < 0.05). The interaction between the two main effects was also significant (P < 0.05). Overall, the highest bond strengths were found when the low-pressure silicate ceramic deposition system (CJ-S) was used, with or without silane.     

Starch utilization by Bacteroides ovatus isolated from the human large intestine

OBJECTIVE: It was hypothesized that there is an inverse relationship between resin-enamel bond strength and bonded cross-sectional area, and that there are regional differences in resin-enamel bond strength. METHODS: The facial and lingual surfaces of extracted human third molars were ground down 0.3 mm using 240 grit abrasive paper and were then bonded with either Clearfil Liner Bond 2 or Scotchbond Multi-Purpose Plus adhesive systems using the manufacturer's instructions. The bonded surfaces then received a resin composite build-up. After 24 h of storage in water, the bonded teeth were vertically serially sectioned into 1.0 mm thick slabs using a diamond saw, and the bonded surface area at the resin-enamel interface was varied from 0.5 to 3.0 mm2 using a diamond saw under microscopic observation. The trimmed region was varied from the occlusal third of the facial or lingual enamel to the middle third, to the cervical third. The trimmed specimens were then glued to a Bencor Multi-T device, placed in an Instron testing machine and stressed to failure at 1 mm/min. A three-factor ANOVA was used to compare bond strengths (buccal vs. lingual, occlusal vs. middle vs. cervical-third, vs. materials). Regression analysis was used to examine the relationship between bond strength and bonded cross-sectional area for each material on occlusal enamel. RESULTS: For both bonding systems, there was a highly significant (p < 0.001) inverse exponential relationship between tensile bond strength (y axis) and bonded cross-sectional area (x axis) with y intercepts of 51 and 59 MPa for Clearfill Liner Bond 2 and Multi-Purpose Plus, respectively. Using both materials, the highest bond strengths were measured in the occlusal third, which were significantly higher (p < 0.05) than those made to cervical enamel. SIGNIFICANCE: Like resin-dentin bonds, resin-enamel bonds exhibit an inverse relationship with cross-sectional area. This relationship becomes more apparent at bonded surface areas below 2 mm2 and is probably due to reductions in the number of interfacial stress-raisers as samples are made smaller.