预合金粉含量对铁基胎体微观组织及性能的影响

研究添加2%、6%、10%和14%质量分数的CuZnSn预合金粉,对金刚石陶瓷磨边轮铁基胎体热压烧结组织、物相组成及力学性能的影响。结果表明:不添加预合金粉烧结的铁基胎体主要包括灰白色、浅灰色和深灰色3种组织,存在的物相主要为γ-Fe、(Cu, Sn)和(γ-Fe, Ni)固溶体以及Fe₄Cu₃、Cu₄₁Sn₁₁、Ni₄Sn等金属间化合物;加入预合金粉后,烧结工艺相同时,胎体中灰白色组织面积明显减少,浅灰色组织面积增加,深灰色组织面积变化不明显,除上述物相外,还出现了Cu_0.61Zn_0.39和CuZn₂物相。随着CuZnSn预合金粉含量增加,铁基胎体的致密度、硬度、抗弯强度均呈先增大后减小的趋势,而磨损量则呈先减少后增加的趋势;在CuZnSn添加质量分数为6%时,分别达到最大值99.8%、104.4 HRB、947.2 MPa和最小值0.272 5 g。添加适量CuZnSn预合金粉可以增加铁基胎体的液相量,改善粉体流动性,提高胎体性能,添加过量则会降低其综合性能。      

预合金粉结合剂真空无压烧结制备金刚石工具

以Fe₄₀Cu₄₀Co₂₀和Cu₈₀Sn₂₀预合金粉为结合剂,采用真空无压烧结制备金属胎体样品,并与相同烧结工艺下的金属单质粉结合剂烧结样品进行对比。用扫描电子显微镜、洛氏硬度计、阿基米德排水法对所得样品的微观形貌、硬度和相对致密度进行对比分析。研究发现:随温度升高,两类样品的致密度和硬度均先增大后减小;当烧结温度达到860℃时,致密度和硬度均达到最大值。预合金粉在860℃下烧结所得样品的相对致密度比同条件下烧结的金属单质粉样品的提高5%,硬度提高HRB 7 MPa。因此,在达到同等级性能的前提下,预合金粉真空烧结所得样品的烧结温度更低,可有效避免在高温条件下金刚石的强度和质量损失。      

CSB-2预合金粉质量分数和烧结温度对热压富铁基胎体力学性能的影响

热压富铁基金刚石钻头具有成本低、钻速高的优点,已在钻探中广泛应用。对比相同的热压富铁基胎体配方,通过测试试样的致密度、显微硬度、抗弯强度和抗冲击韧性,研究CSB-2预合金粉质量分数和烧结温度对金刚石钻头胎体力学性能的影响。试验结果表明:添加CSB-2预合金粉的胎体性能均比单质混粉胎体性能好。随CSB-2质量分数的增加,胎体的致密度、显微硬度、抗弯强度和抗冲击韧性分别最大提高了7.68%、27.99%、94.43%和312.82%;同时,胎体粉末预合金化有利于降低胎体的热压烧结温度;为获得良好的应用效果,CSB-2质量分数应大于30%,且最佳烧结温度为940~980℃。      

FeCoCu预合金粉末含量和烧结温度对碳化钨基钻头性能的影响

为提高钻头胎体耐磨性与地层研磨性的适应性,提高钻头自锐能力,选取FeCoCu预合金粉作为胎体成分,对胎体性能进行研究。在碳化钨基胎体中添加FeCoCu预合金粉末,调节金刚石钻头胎体中FeCoCu粉末与WC粉末的配比关系,并在不同的烧结温度下烧制试样,寻找FeCoCu含量和烧结温度对胎体性能的影响规律。试验结果发现：随着FeCoCu含量的升高,胎体的相对致密度、洛氏硬度、抗弯强度和耐磨性随之降低;烧结温度对相对致密度、洛氏硬度、抗弯强度的影响幅度小,对胎体耐磨性的影响幅度大,最大变化幅度达到310%。FeCoCu预合金与烧结温度的耦合作用下,胎体的耐磨性变化存在较宽的调节区间,可通过二者组合的变化,调节胎体耐磨性,提高胎体对地层的适应性。     

机械活化Ti_(47)Ni_(47)Al_6粉末的烧结性能

采用机械活化和粉末冶金方法制备Ti47Ni47Al6合金,通过光学显微镜、配备能谱分析的扫描电镜、X射线衍射仪、维氏硬度及抗弯强度测试手段研究机械活化对烧结合金显微组织和性能的影响。结果表明:随着球磨的进行,粉体中Ti和Ni的晶格常数增大,球磨20 h的Ti47Ni47Al6粉末形成了Ti-Ni-Al三元复合粉,但无新相形成。与球磨1 h粉末烧结制备的合金相比,球磨20 h的机械活化粉末烧结合金中Ti2Ni(Al)和Ni3Ti(Al)强化相数量、致密度、硬度及抗弯强度均增加。     

FeNiCo预合金粉末的烧结特性及其在金刚石绳锯中的应用

通过多金属电解法制备FeNiCo预合金粉末,采用X射线衍射仪和扫描电子显微镜对预合金粉末及其烧结体进行形貌观察和物相分析,研究FeNiCo预合金粉不同温度烧结时烧结体的力学性能和磨损性能,并探讨其在金刚石绳锯中应用的可行性。结果表明:制备的FeNiCo预合金粉一定程度上实现合金化,粉末呈不规则状,粒度较细;FeNiCo预合金粉在800~840℃烧结时,烧结体硬度最大值为107.6 HRB,三点抗弯强度最大值为1638.3MPa,致密度最大值为96.2%,磨损质量损失为0.498~0.555g,烧结温度适应性较好。采用FeNiCo预合金粉为主要胎体成分制作金刚石绳锯锯切硬质石材时,切割效率为8.6 m~2/h,工具寿命为11.3 m~2/m,具有较好的综合使用性能。     

铬对FeNiMoCu系预合金粉末烧结性能的影响

将Cr以铬铁的形式加入到FeNiMoCu系预合金粉末中,经充分混合后单轴600MPa下压制,然后分别采用冷压烧结、烧结热锻和复烧工艺,研究铬对FeNiMoCu系预合金粉末烧结密度、组织及性能的影响.实验结果表明,添加到预合金粉末中的铬在1573K温度烧结时可均匀扩散到组织中,使组织性能得到改善;随添加的铬量和复烧温度的提高,微观组织硬度和表观硬度逐渐增加,经热锻及热锻复烧可获得较高的烧结密度和硬度.当复烧温度为1573K时,Fe-1.5Cr-2.0Ni-0.85Mo-1.7Cu-0.5C获得的密度为7.71 g/cm3,硬度为105HRB;Fe-4.0Cr-3.0Ni-0.85Mo-1.7Cu-0.5C获得的密度为7.63g/cm3,硬度为105HRB.     

粉末粒度对SPS固相烧结La0.6Eu0.4B6阴极材料的影响

采用高能球磨法制备出La_0.6Eu_0.4B₆纳米粉体,将球磨后的纳米粉进行放电等离子（SPS）烧结,制备出了高致密的La_0.6Eu_0.4B₆多晶块体材料。系统研究了烧结温度、烧结压力对样品致密度和力学性能的影响。结果表明,该方法与传统热压烧结方法相比有效降低了烧结温度,制备出的样品密度、维氏硬度和抗弯强度分别达到4.71g/cm3、23.37GPa和295.14MPa,这些值均高于传统热压烧结方法。热电子发射结果表明,当阴极温度为1873K时,最大发射电流密度为33.74A/cm2。实验过程中还发现,在相同烧结工艺下,球磨纳米粉与粗粉相比,维氏硬度、抗弯强度和热电子发射电流密度分别提高了28%、58%和32%。因此,在固相烧结过程中,粉末粒度的减小,更有助于烧结性能的提高。     

金刚石工具用FeCoCu预合金粉组成对烧结特性的影响

通过共沉淀法制备不同Fe-Cu配比的FeCoCu预合金粉,并对其微观结构进行表征与分析。同时,对3种粉体进行不同温度下的烧结实验和对烧结试样块进行力学性能及磨损质量损失进行测试,并对预合金粉与金刚石的界面结合情况进行探讨。结果表明:预合金粉中形成了Co_3Fe_7、CoFe_(15.7)、FeCu_4等中间相,在一定程度上实现合金化。3种预合金粉末的形状均为不规则状,粉末颗粒较细,且相互连接,表面疏松,有利于烧结。3种预合金粉中单质相仍占有较大比例,单质配比对烧结体性能有重要影响。Fe含量增加时,试样的理想烧结温度及烧结体力学性能均升高。Fe-Cu配比会对微观结构产生重要影响,胎体对金刚石以机械包镶为主,结合XRD及Raman光谱可知,与预合金粉烧结后的金刚石表面发生石墨化。     

第二代FeCuCo预合金粉末的烧结与力学性能研究

采用国产真空热压烧结机制备了第二代FeCuCo预合金粉末的胎体试样,着重研究了不同烧结温度对胎体的断口形貌、相对密度、硬度和抗弯强度的影响。结果表明:在选定的不同热压烧结温度下,胎体的断口均为沿晶断裂和穿晶断裂的混合型断口,胎体的晶粒尺寸比较均匀;随着烧结温度的升高,胎体内的晶粒逐渐长大,但没有发生异常长大现象,胎体的相对密度先略有升高然后恒定不变,硬度一直呈下降趋势,抗弯强度先升高后下降;在30 MPa保压6 min的条件下,第二代FeCuCo预合金粉末的最佳烧结温度为850℃,此时胎体的相对密度为97.5%,硬度为105.5 HRB,抗弯强度为1 839.14MPa。     

金刚石工具用适配型CuSnZnNi预合金粉末的研制

在CuSn合金中添加Zn、Ni元素研制一种CuSnZnNi适配型预合金粉,克服了 CuSn10合金硬度低,对金刚石把持力弱,通用性欠佳等问题.通过添加质量分数为20％的Zn元素研制了 CuSnZn合金,相对CuSn10合金固液相温差由170℃降为34℃,合金的流动性得到显著提升.电子显微镜分析表明:随着Zn元素加入,(...     

Characterizations and mechanical properties of impregnated diamond segment using Cu-Fe-Co metal matrix

Diamond impregnated Cu-Fe-Co based saw-blade segments are directly processed by vacuum and pressure-assisted sintering at different temperature,with the purpose of reducing the cobalt content in diamond tools.Copper and iron are used as the bonding elements and cobalt-chrome pre-alloyed powder is used as the hardening phase.Effects of sintering temperature on microstructures and mechanical properties of the sintered matrix and diamond graphitization were investigated by X-ray diffraction analysis,electron probe micro-analyzer,universal testing machine,digital Rockwell hardness tester and Raman scattering analyzer.Results showed that microstructures of the sintered matrix were refined and porosities in the sintered matrix were closed to a more spherical-like shape with the increase of the sintering temperature.Densification,hardness and tensile strength of the matrix sintered at 820 ℃ were 12.75％,2.72％ and 156.38％ higher than that of the matrix sintered at 740 ℃,respectively.Diamond graphitization was not occurred at 820 ℃.The hardness and the tensile strength rose 32.8％ and 13.5％,respectively,after 7.5 h ageing treatment.The matrix densification ascent and the dispersed distribution of Co-Cr pre-alloyed powders contributed a hardness improvement and a tensile strength improvement to the Cu-Fe based matrix.     

水气联合雾化法制备铁基预合金粉末及其在金刚石工具中的应用

采用水气联合雾化工艺制备了金刚石工具用铁基预合金粉末,对水气联合雾化法、常规水雾化法制备的预合金粉末进行物性对比,并对相应地预合金粉末烧结块的断口形貌、力学性能进行比较与分析。结果表明:水气联合雾化工艺制备的预合金粉末氧含量较低,球形度好,粉末粒度细;水气联合雾化制备的预合金粉末TZ611烧结块断口形貌呈典型的韧性断裂和沿晶断裂特征;烧结块相对密度、硬度和抗弯强度等力学性能显著提高,对金刚石颗粒把持更好。采用水气联合雾化工艺制备的预合金粉末制造的圆锯片切割更为锋利,且使用寿命为常规水雾化粉末的1.62倍。      

P元素加入形式对铁基金刚石工具胎体组织性能的影响

以常用的CuP8,FeP24两种预合金粉作为研究对象,运用SEM,EDS,硬度和抗弯强度等研究分析手段,研究了以不同形式加入P元素对铁基金刚石工具胎体组织性能的影响. 结果表明,烧结后胎体组织由α-Fe、含铁固溶体(Cu)、Fe₃C化合物组成,加入FeP24的烧结胎体中还存在Fe₂P和FeP化合物. P元素加入形式对胎体性能影响显著,向胎体中加入CuP8,P元素几乎全部脱离CuP8进入铁基体,相比于加入FeP24的胎体,P元素分布更均匀,胎体硬度、抗弯强度等性能指标均有提高. FeP24在热压过程中会产生微裂纹,这些微裂纹可能成为基体的裂纹源而降低胎体的抗弯强度. 因此,选用CuP8预合金粉更有利于获得高性能铁基金刚石工具胎体.     

Effect of Fe-based pre-alloyed powder on the microstructure and holding strength of impregnated diamond bit matrix

An iron-rich pre-alloyed powder was selected out, and the pre-alloying degree of matrix materials and the sintering temperature were considered to investigate the effect of the Fe-based pre-alloyed powder on the microstructure and holding strength of impregnated diamond bit matrix. And relative density and bending strength of the specimens were measured, and then the resulting fracture surfaces were analyzed using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The results showed that the relative density, bending strength and plasticity of matrix materials are increased with the sintering temperature and the pre-alloying degree. The influence of the pre-alloying degree on them is more significant than that of the sintering temperature within the experimental parameters. Besides, Fe-based matrices have thermal corrosion effect on diamonds at high temperature sintering process. And the rate of diamond graphitization has a greatly increase with the sintering temperature changes from 900 °C to 1020 °C and the holding strength decreases. A low pre-alloying degree accelerates the rate of diamond graphitization. But an adequate pre-alloying degree of Fe-based matrix materials is conducive to improve the wettability of the matrix to diamonds, alleviate the diamond graphitization, reduce the diamonds' thermal damage and improve the holding strength. Besides, it can also greatly reduce the sintering temperature and broaden the sintering temperature range. In a word, it is feasible and reasonable that Fe-based pre-alloyed powders replace Fe elemental powders to fabricate impregnated diamond bits. And it has a good economic value and broad application prospect.     

锡青铜粉末的压制与烧结性能

采用预合金粉、部分合金化粉、混合粉，制得具有理想物理性能、压制性能和烧结性能的Ｃｕ－Ｓｎ粉末，研究了粉末组成对压坯密度、压坯强度、烧结后尺寸变化、烧结密度和烧结强度等性能的影响。     

Microstructure and mechanical properties of porous yttria stabilized zirconia ceramic using poly methyl methacrylate powder

Porous t-ZrO₂ ceramic was fabricated by pressureless sintering, using commercial t-ZrO₂ and different volume percentages of poly methyl methacrylate (PMMA) powders (20–80%). The spherical pores ranged from about 120 to 170 μm in diameter. By increasing the PMMA content, the number of pores, material properties and pore morphology were changed dramatically. The values of relative density, elastic modulus, bending strength and hardness of the 60 vol.% PMMA content sample, sintered at 1550 °C, were about 43%, 40 GPa, 170 MPa and 248 Hv, respectively.     

铜磷预合金粉在金刚石工具中的应用

在金刚石工具中添加铜磷预合金粉,热压烧结过程中铜磷预合金粉瞬时液化对铁铜基础粉形成钎焊连接,烧结体的致密度、硬度、强度均得到提高。铜磷预合金粉改善单质铁粉和铜粉的润湿性和结合力,并在晶界处生成脆性化合物,增加烧结体的脆性,提高了金刚石工具的锋利度,在金刚石工具行业中具有广阔的应用前景。