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热等静压工艺对硬质合金性能的影响 总被引:5,自引:0,他引:5
应用烧结加热等静压和烧结-热等静压两种工艺制备了粗晶WC-15Co、WC-22Co和微晶WC-12Co-1Cr3C2、中等晶粒WC-12Co硬质合金,从原理、经济性论述了这两种工艺的差异及其对WC-Co硬质合金组织和性能的影响。结果表明,烧结-热等静压制作的硬质合金孔洞消除了,并且硬质合金的抗弯强度和弯曲疲劳寿命也大幅度提高。 相似文献
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我国矿用硬质合金的发展现状与趋势 总被引:1,自引:0,他引:1
孙东平 《粉末冶金材料科学与工程》1998,(4)
通过对我国矿用硬质合金发展历史和现状的分析,指出了我国部分矿用硬质合金生产厂家经过20世纪80年代以来大规模的技术引进和技术改造,其生产技术、工艺装备和产品质量都有较大幅度的提高,部分厂家生产的矿用硬质合金质量已达到世界先进水平。在分析近几年来我国矿用硬质合金理论研究现状的同时,提出了我国矿用硬质合金21世纪的发展趋势:即喷雾制粒、低压烧结等先进的矿用硬质合金生产技术和设备被各生产厂家普遍采用。梯度结构和超细晶粒硬质合金生产将在矿用硬质合金市场上不断推广和应用。矿用硬质合金的强化处理,如热处理、深冷处理、等离子注入等作为提高矿用硬质合金综合机械性能的有效手段,将得到广泛应用。 相似文献
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WC-(Co-Al)硬质合金的研究 总被引:4,自引:1,他引:4
研究采用反应烧结制备以Co3 Al代Co作为粘结金属的硬质合金技术。对制得的硬质合金进行了组织结构的观察及性能测定。结果表明 ,铝的加入有助于烧结过程中WC晶粒的细化和均匀化 ,制得了WC晶粒均匀的超细硬质合金。与相同粘结剂含量的钴粘结硬质合金相比 ,在耐腐蚀和高温抗氧化性方面 ,Co Al硬质合金表现出明显的优异性能。研究发现 ,在烧结中由于发生Co Al的激烈化合反应而导致孔隙的形成。采用低压等静压烧结或烧结后进行低压等静压处理可降低孔隙度提高合金的力学性能 相似文献
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采用低压热等静压工艺制取再生矿用硬质合金的横向断裂强度高,孔隙度可降低到A00,使用寿命不逊于正常合金。此外,还对低压热等静压的致密化机理进行了分析 相似文献
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硬质合金低压热等静压烧结工艺 总被引:12,自引:1,他引:11
低压热等静压烧结工艺技术能最大限度地消除合金内部残余孔隙、细化晶粒、克服常规热等静压给合金造成的粗晶、钴池和表面成分改变的缺陷,显著提高硬质合金物理-力学性能,并能有效校正合金碳含量。 相似文献
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This paper introduces a domain-specific search engine, which was developed to take advantage of the growing online product information for surveying the virtual product market. Knowledge about a product was uniquely incorporated with query expansion operations and the extended Boolean model retrieval approach to handle issues associated with the search engine development. The search engine was designed to (1) represent and utilize the represented knowledge in the product domain; (2) identify online product information; and (3) then evaluate the collected online product information. A prototype search engine for testing was developed and statistically validated with five data sets with each data set being derived from a different type of product according to MasterFormat (Alexandria, Va.) categorization. The validation results indicated that compared with the tested general search engine or aggregated information service, the prototype was able to identify more distinct product manufacturers for procurement-related decision support. 相似文献
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A liquid yeast product (about 11% DM), produced as a by-product of riboflavin synthesis, was incorporated into a TMR at three concentrations to determine the maximal inclusion rate and acceptability as a feed supplement in diets of lactating cows. Twelve Holstein cows in midlactation were randomly assigned to TMR treatments containing (as-fed basis) 1) no yeast product (control), 2) 20% dietary yeast product, or 3) 40% dietary yeast product in a 3 x 3 Latin square design with 3-wk periods. Dietary DM contents were 90, 74.2, and 58.4% for the 0, 20, and 40% yeast product TMR, respectively. The control TMR was based on a 45:55 ratio (DM basis) of mixed concentrate and chopped alfalfa hay. The DMI decreased linearly with increasing percentages of dietary yeast product. Milk yield and milk protein percentage were not altered by inclusion of the dietary yeast product. Milk fat tended to respond quadratically to increases in the percentage of dietary yeast product in the TMR. The supplemental dietary yeast product had no effect on ruminal pH; however, the ratio of acetate to propionate decreased, and propionate percentage tended to increase, as supplementation of the yeast product increased. Addition of yeast product to the TMR had no adverse effect on milk flavor. Milk from cows fed yeast product had better flavor than milk from control cows. Results indicate that inclusion of this yeast product at 40% depressed feed intake. 相似文献
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板带材产品结构调整与产品开发 总被引:2,自引:0,他引:2
从近年来我国板带轧机类型、产品规格和生产量分析研究了钢材结构的调整问题,提高板带比仍然是我国钢材生产结构调整的重要方向。认为经过多年品种结构调整,但在板带总产量和品种上尚有一些差距;增加板带产量的顺序是冷轧板带、热轧薄板带、中厚板;提高板带比还要注意产品规格细分方面的调整和轧机机型的配置;新建板带厂应研究国外板带轧机近年发展动向,缩减产量,增加灵活性;并提出了我国目前板带材品种开发的重点。 相似文献
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Proposes an explicit definition of consumers' product expectations as pretrial beliefs about the product. Specific expectations about a product characteristic were created by exposing 38 married female consumers to 3 advertisements, each of which described 1 salient attribute of the product (ground coffee). These expectations were then negatively disconfirmed by a controlled trial experience with the product. For a wide range of cognitive variables, the disconfirmation caused negative changes in product evaluations. However, postdisconfirmation evaluations were not so negative as the product ratings of a nondisconfirmed control group that merely evaluated the product in absence of manipulated expectations. Results are consistent with both dissonance and assimilation–contrast theory. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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GB/T 19001标准8.3条款对组织的不合格品控制提出了明确要求,笔者结合标准要求和审核,明确了不合格品控制的对象与目的,指出了公司在原辅料、过程产品、中间产品、成品不合格品控制过程中存在的问题,并从职责权限、产品接收准则、数据分析与预防措施、纠正措施等方面提出了不合格品控制工作的改进思路。 相似文献
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论述了海绵钛产品的杂质分布及其对产品质量的影响,针对杂质分布的不均匀性,提出了生产中改善产品质量的措施,对产品进行处理,分部包装,以保证产品质量,提高合格率。 相似文献
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阐述了新产品开发的重要性和必要性,开发新产品应遵循的原则及开发策略,论述了边缘产品的功能和效用,提出了降低新产品开发风险的措施。 相似文献
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以热镀锌渣为原料,空气为氧源,通过真空控氧法制得了纯度大于99.98%的纳米氧化锌,探讨了反应温度和体系的真空度对产物形貌的影响,研究了原料中的主要杂质元素在不同氧化条件下的行为及其对产物品质的影响.结果表明:不同的反应温度或体系的真空度对产物的形貌影响很大;当控制温度和真空度在适当范围时,产物大多为六方纤锌矿结构的纳米四针状氧化锌,针体细长,长径比较大;杂质元素Fe和Pb在不同氧化条件下的不同行为对产物品质产生不同的影响;铁进入产物主要是因为锌的机械夹带作用和Fe-Zn系正偏差效应,而铅进入产品中是因为自身的蒸气压和Pb-Zn系正偏差效应. 相似文献
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Strick Madelijn; van Baaren Rick B.; Holland Rob W.; van Knippenberg Ad 《Canadian Metallurgical Quarterly》2009,15(1):35
Humor in advertising is known to enhance product liking, but this attitude change is often considered nonpredictive of product choice. Previous research relied exclusively on explicit self-report measures to assess attitudes and purchase intentions. The present research shows that unobtrusive association of a product with humor can affect persuasion through implicit attitude change. Participants viewed humorous and nonhumorous cartoons in a mock-up magazine. One of two products was consistently presented in the vicinity of the humorous cartoons, whereas the other product was consistently presented in the vicinity of the nonhumorous cartoons. The results of an evaluative priming task showed enhanced evaluations of products paired with humor (Experiment 1, 2, and 3). Furthermore, these enhanced evaluations mediated the relation between association with humor and product choice (Experiment 2 and 3). Paradoxically, products paired with humor were also less recognized than the control products (Experiments 2 and 3). In summary, the present research demonstrates that mere association with humor enhances product evaluations and product choice in a way that is dissociated from the accessibility of the product in memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献