不同复合烧结助剂对气压烧结Si3N4陶瓷性能的影响

以Y₂O₃/Al₂O₃、Al₂O₃/MgO和Y₂O₃/Al₂O₃/MgO等为复合烧结助剂,研究烧结助剂类别及烧结温度（1 750、1 800、1 850℃）对气压烧结Si₃N₄陶瓷致密化、显微结构以及力学性能的影响。结果表明：以Y₂O₃/Al₂O₃为烧结助剂所制备样品的抗折强度、硬度和断裂韧性优于其他两种复合助剂制备试样的;Y₂O₃/Al₂O₃复合助剂有利于显微结构中高长径比β-Si₃N₄晶粒的形成。当烧结温度为1 800℃时,以Y₂O₃/Al₂...     

Cr2O3微粉加入量对Al2O3-Cr2O3质耐火材料性能的影响

以电熔铬刚玉和白刚玉为主要原料,用Cr₂O₃微粉部分替代电熔铬刚玉细粉,研究了Cr₂O₃微粉加入量对Al₂O₃-Cr₂O₃质耐火材料常温和高温性能、物相组成和显微结构的影响。结果表明,随着Cr₂O₃微粉加入量的增加,原位形成了(Al_1-xCr_x)₂O₃固溶体,促进了烧结,材料的显气孔率先降低后升高,且(Al_1-xCr_x)₂O₃固溶体的晶格常数呈线性增加,符合Vegard定律。材料的常温抗折强度和常温耐压强度随Cr₂O₃微粉加入量的增加先升高后降低,在Cr₂O₃微粉加入量为15%(质量分数)时强度达到最大值。而当Cr₂O₃微粉加入量为20%(质量分数)时,由于有挥发现象,材料显气孔率上升,强度下降。材料高温抗折强度随Cr₂O₃微粉加入量的增加而增加,材料的残余强度保持率呈先降低后升高的趋势。     

烧结温度对氮化硅陶瓷球显微结构和力学性能的影响

以α-Si₃N₄粉为原料,纳米级Y₂O₃和Al₂O₃为烧结助剂,采用气压烧结工艺制备氮化硅陶瓷球,研究了烧结温度对陶瓷球显微结构及力学性能的影响。结果表明,随着烧结温度的升高,陶瓷球的维氏硬度和压碎强度先提高后降低,断裂韧性不断提高。烧结温度为1780 ℃的陶瓷球综合力学性能最佳,其相对密度达到了99%,维氏硬度、断裂韧性和压碎强度分别为1 530 HV、7 MPa·m^1/2、296 MPa。     

TiO2加入量对光固化打印成型Al2O3陶瓷性能的影响

以光敏丙烯酸树脂与分散剂SP-710为液相，以d₅₀=2.38μm的Al₂O₃粉和添加剂TiO₂粉为固相，制备了固含量为78%（w）的Al₂O₃陶瓷浆料。采用数字光固化成型技术（DLP）打印Al₂O₃陶瓷素坯，经1 450、1 500、1 550、1 600℃保温4 h烧后，分析TiO₂加入量（质量分数分别为0、1%、2%、3%、5%）对Al₂O₃陶瓷试样性能的影响。结果表明：TiO₂的加入可促进Al₂O₃陶瓷的烧结，显著提高致密性，降低烧结温度，并确定TiO₂最优掺量为3%（w）,烧结温度最优为1 600℃,此时试样在x轴、y轴、z轴的收缩率分别为15.7%、15.8%与23.8%,显气孔率为2.41%,体积密度为3.74 g·cm^-3,...     

MnO2-CuO-TiO2共掺Al2O3陶瓷低温烧结和微波介电性能的研究

作为重要微波介质材料之一,Al₂O₃陶瓷介电性能优良,在微波电路方面得到广泛应用。但Al₂O₃陶瓷的烧结温度较高,制备工序需消耗大量能源。低成本降低烧结温度对Al₂O₃陶瓷的进一步发展具有重要意义。本论文通过MnO₂-CuO-TiO₂掺杂实现了Al₂O₃陶瓷的低温烧结,并对其烧结行为和微波介电性能进行了研究。结果表明,MnO₂、CuO、TiO₂的质量分数分别为0.7%、0.5%、0.8%时,复合掺杂可以大幅降低Al₂O₃陶瓷的烧结温度,所获陶瓷具有良好的微波介电性能。在烧结温度为1 250℃时,Al₂O₃陶瓷的密度可达3.92 g/cm³,介电常数ε_r=10.02,品质因子与谐振频率的乘积Q×f值...     

防护装甲用抗弹Al2O3陶瓷研究进展

抗弹Al₂O₃陶瓷因其高硬度、低密度以及低成本,在防护装甲领域占有重要地位。本文详尽综述了抗弹Al₂O₃陶瓷的生产原材料选择、制备技术及发展趋势,比较了干压成型、等静压成型、凝胶注模成型及粉末微注射成型技术,与常压烧结、热压烧结、热等静压烧结等烧结工艺对抗弹Al₂O₃陶瓷性能的影响,阐述了发展抗弹Al₂O₃透明陶瓷以满足当代军事需求、抗弹Al₂O₃陶瓷增韧化以克服其高脆性、低韧性的应用屏障,为抗弹Al₂O₃陶瓷的更多应用提供可能。     

Al2O3含量对PbO-CaO-B2O3-SiO2系玻璃析晶行为与烧结性能的影响

PbO-CaO-B₂O₃-SiO₂系玻璃粉体是耐高过载低温共烧陶瓷(LTCC)生瓷带的主要组成部分。玻璃粉体的析晶行为影响烧结性能,进而决定基板的使用性能。本文研究了Al₂O₃含量对PbO-CaO-B₂O₃-SiO₂系玻璃析晶行为与烧结性能的影响。结果表明:向PbO-CaO-B₂O₃-SiO₂系玻璃中引入Al₂O₃可抑制玻璃析晶,防止高膨胀晶相的析出,并提高玻璃烧结密度;不含Al₂O₃的PbO-CaO-B₂O₃-SiO₂玻璃粉体析晶峰温度为862 ℃,烧结过程中析出方石英晶相,20~200 ℃的平均线膨胀系数高达260.8×10^-7 ℃^-1;引入2.1%(质量分数)Al₂O₃可显著抑制玻璃析晶,700 ℃烧结后膨胀系数降低至72.9×10^-7 ℃^-1,介电常数显著增大,由6.30提高至7.02。     

组成对钠铝硅玻璃中钇锆酸盐纳米晶析晶性能的影响

基于含Y₂O₃和ZrO₂的钠铝硅玻璃体系,研究了玻璃组分中Al₂O₃/Na₂O摩尔比值(M_AN)与SiO₂/Al₂O₃摩尔比值(M_SA)对玻璃析晶性能的影响。研究结果表明,当M_AN<1时,玻璃经热处理后表面析出钠霞石晶体;当M_AN≥1时,玻璃热处理后析出钇锆酸盐纳米晶体,且此时微晶玻璃仍然具有不小于90%的高可见光透过率。对于固定M_AN的玻璃,调整其M_SA也能实现钇锆酸盐纳米晶的析出,且析出晶体尺寸随M_SA增加而减小。随着热处理温度升高微晶玻璃样品中纳米晶体尺寸增大,维氏硬度也增大。     

两种氧化铝粉对熔铸AZS耐火材料结构和性能的影响

熔铸Al₂O₃-ZrO₂-SiO₂(AZS)耐火材料是玻璃熔窑的关键筑炉材料。本文分别以煅烧氧化铝粉和普通工业氧化铝粉为原料制备熔铸AZS耐火材料,并采用岩相分析、X射线衍射分析和能谱分析等测试方法,对比分析了两种熔铸AZS耐火材料的结构和性能。结果表明：普通工业氧化铝粉制备的熔铸AZS耐火材料中存在未转化完全的γ-Al₂O₃,导致获得的Al₂O₃-ZrO₂共晶体分布不均匀。煅烧氧化铝粉制备的熔铸AZS耐火材料中,氧化铝物相为α-Al₂O₃,其晶体结构中斜锆石少,Al₂O₃-ZrO₂共晶体多,玻璃相分布均匀。晶体结构的分布影响着玻璃相渗出量和抗玻璃液侵蚀性能。煅烧氧化铝粉制备的熔铸AZS耐火材料玻璃相渗出量比普通工业氧化铝粉制备的熔铸AZS耐火材料玻璃相渗出量降低了0.57个百分点,...     

金刚石增强Na2O-B2O3-Al2O3-SiO2系陶瓷基复合材料的界面研究

以Na₂O-B₂O₃-Al₂O₃-SiO₂系低温玻璃为基础结合剂烧制金刚石增强陶瓷基复合材料,利用扫描电子显微镜、X射线能谱、X射线光电子能谱、拉曼光谱及力学性能测试仪等对其界面结合强度、界面处元素分布及界面化学键进行了表征。结果表明,Na₂O-B₂O₃-Al₂O₃-SiO₂系陶瓷结合剂与金刚石颗粒界面结合强度高,790 ℃煅烧时试样抗折强度达到77.82 MPa。Si、B、Na、Zn各元素在界面位置发生扩散,而Al元素没有明显扩散,元素扩散提升了结合剂对金刚石的把持力。陶瓷结合剂与金刚石在界面处形成C-O、C=O和C-B键,化学成键进一步增进界面结合。另外,790 ℃煅烧的复合材料中金刚石颗粒保存完好,而850 ℃煅烧时金刚石出现石墨化迹象。     

Effects of Ni addition on properties of vitrified bond CBN composites in strong magnetic field

Properties of vitrified bond with varying Ni doping amounts were extensively investigated. Effects of Ni addition on microstructures and properties of vitrified bond cubic boron nitride (CBN) composites prepared in strong magnetic field were investigated for applications in CBN grinding tools. Vitrified bond was characterized using three-point bending, scanning electron microscopy, X-ray diffraction and other methods. The refractoriness, fluidity, and bending strength of vitrified bond were evaluated. Bending strengths, microstructures, and phase compositions of vitrified bond CBN composites achieved using conventional and strong electromagnetic sintering techniques were compared. Results show that the addition of Ni to vitrified bond CBN composites improved the fluidity and bending strength of the vitrified bond. Strong electromagnetic sintering improved the mechanical strength and pore structure of vitrified bond CBN composites. Moreover, the introduction of the strong magnetic field facilitated Ni migration and aggregation in vitrified bond, rotated abrasives, and formed new substances, thus increasing the stability of vitrified bond CBN composite thermal material. Also, strong magnetic field inhibit grain growth of non-magnetic and ferromagnetic materials with fine-grain effect.     

Effect of TiO2 addition and high magnetic field sintering on properties of vitrified bond CBN composites

Vitrified bond CBN composites, with different amounts of TiO₂ doping, were prepared by conventional sintering and high magnetic field sintering processes. Mechanical properties, cross-sectional morphology, refractoriness, fluidity and structural characterization have been carried out to understand the role of TiO₂ addition and sintering conditions. Results show that TiO₂ addition significantly affected bending strength, refractoriness and fluidity of vitrified bonds. In addition, high magnetic field sintering improved bending strength and the microstructure of vitrified bond CBN composites. Due to high magnetic field sintering, CBN grains were completely covered by vitrified bond and exhibited fewer pores. In addition, high magnetic field promoted the growth of specific grains, such as SiO₂, whereas suppressed grain growth of other crystal phases, such as NaAlSi₃O₈.     

Bi2O3/B2O3比及β-锂霞石粉对MEMS封接玻璃结构与性能的影响

针对微机电系统(MEMS)封接玻璃的性能要求,本文制备了Bi₂O₃-B₂O₃-ZnO-BaO-CuO系无铅玻璃粉,采用拉曼光谱仪、X射线衍射仪、热膨胀仪、烧结影像仪、扫描电子显微镜等测试手段分别表征了Bi₂O₃和B₂O₃物质的量比(n(Bi₂O₃)/n(B₂O₃))和β-锂霞石粉掺量变化对玻璃结构、热学性能、封接温度及微观形貌的影响。结果表明:随着n(Bi₂O₃)/n(B₂O₃)的增大,玻璃结构中[BiO₃]三角体和[BiO₆]八面体单元含量逐渐增多,[BO₄]四面体向[BO₃]三角体转变,导致玻璃网络连接强度减弱、结构变疏松;随着n(Bi₂O₃)/n(B₂O₃)的增大,玻璃热膨胀系数逐渐增大,特征温度和封接温度逐渐降低,但后期变化放缓;随着β-锂霞石粉外掺量的增加,复合玻璃粉的热膨胀系数明显降低,而特征温度和封接温度没有明显升高,但复合玻璃粉的流动性变差。     

碱金属氧化物Na2 O对陶瓷结合剂金刚石磨具性能的影响

通过调整陶瓷结合剂中碱金属氧化物Na₂O含量,来探究碱金属氧化物Na₂O对陶瓷结合剂金刚石磨具性能的影响。当n(Na₂O)/n(SiO₂)=0.1时,磨具试样的强度(57.7 MPa)和硬度(117 HRB)达到最大值。随着碱金属氧化物Na₂O添加量的增加,结合剂的耐火度随之显著降低,流动性显著增加。磨具试样断口SEM照片表明,适量的碱金属氧化物Na₂O能够使磨具断面空隙减少,孔隙度降低,结合剂与磨料分布更加均匀,结合剂与磨料结合界面更加紧密。XRD分析表明,磨具试样在720 ℃下烧结,结合剂中除了玻璃相还产生了一种晶相,结合剂中碱金属氧化物Na₂O的含量对烧结后产生的晶相种类无影响。     

Effects of sintering in a high magnetic field on properties of vitrified bond and vitrified CBN composites

Vitrified bond CBN grinding wheels are being widely used due to their superior performance. Also, advantages of vitrified grinding wheels are high elastic modulus, stable chemical property, and low thermal expansion coefficient. Brittleness and low strength are key factors restricting the development of vitrified bond CBN grinding wheels. In this paper, the sintering in a high magnetic field was innovatively introduced into the manufacturing of vitrified bond CBN grinding wheels, and the effects of sintering in a high magnetic field on properties on vitrified bond and vitrified CBN composites were systematically investigated. Vitrified bond was characterized using three-point bending, scanning electron microscopy, X-ray diffraction. It was observed that microstructure of vitrified bond could be changed, grain orientation could be controlled and average grain size could be decreased in a high magnetic field, while vitrified bond strength could be simultaneously improved. High quality vitrified bond could be obtained by appropriately adjusting the strength and direction of high magnetic field. Results demonstrated that vitrified bond properties were improved when the magnetic field strength was 6?T. In order to highlight the high magnetic field effect on the vitrified CBN composites, the ordinary CBN abrasives and nickel plated CBN abrasives were used respectively. Microstructures, bending strengths of vitrified CBN composites were compared in different high magnetic fields. When the magnetic field strength was appropriate (less than 6?T), the binding characteristic of vitrified bond CBN composites with nickel plated CBN abrasives was greatly improved. The highest bending strength value of vitrified CBN composites was 79.5?MPa in 6?T high magnetic field.     

TiO2-Al2O3复合粉体的制备及光催化性能

Al₂O₃陶瓷膜在过滤染料废水过程中容易被染料大分子堵塞,导致Al₂O₃陶瓷膜水通量下降。以钛酸丁酯、异丙醇铝为前驱体,采用溶胶-凝胶法制备Ti(OH)₄-AlOOH复合溶胶,经450 ℃烧成获得TiO₂-Al₂O₃复合粉体。以SEM、纳米粒度/电位仪作为主要表征手段,研究了不同Ti(OH)₄和AlOOH摩尔比对复合溶胶粒径分布的影响,进而探究TiO₂-Al₂O₃复合粉体的光催化性能。结果表明,Ti(OH)₄和AlOOH摩尔比为0~0.4时,随着Ti(OH)₄和AlOOH摩尔比的增大,胶粒的平均粒径从67.5 nm减小到34.0 nm,Ti(OH)₄-AlOOH复合溶胶的电位从43 mV升高至53 mV。当Ti(OH)₄和AlOOH摩尔比为0.4时,复合粉体对结晶紫的去除率高达79.3%,反应速率常数增大到了0.018 min^-1。TiO₂-Al₂O₃复合粉体制备的陶瓷膜能有效降解表面沉积的大分子,解决了陶瓷膜堵塞的问题。     

纳米Al2O3协同水性环氧树脂对水泥基锚固注浆材料改性研究

锚固注浆材料性能良好,可有效提高锚固结构的服役寿命。为解决传统水泥基锚固注浆材料在边坡工程中稳定性和力学性能不足的问题,采用纳米Al₂O₃、水性环氧树脂对水泥基锚固注浆材料进行改性获得复合改性水泥浆材。通过正交试验、扫描电镜和X射线衍射测试,研究不同水灰比及配合比下复合改性水泥浆材的基本性能和改性机制。结果表明,复合改性水泥浆材的流动度、凝结时间、抗压强度受水性环氧树脂掺量的影响均大于纳米Al₂O₃掺量,而漏斗黏度、析水率受纳米Al₂O₃掺量的影响大于水性环氧树脂掺量。复合改性水泥浆材具有稳定性高、析水率低、抗压强度高等特点,有效解决了传统水泥基锚固注浆材料存在的稳定性和力学性能不足的问题,且其最佳性能配合比为水灰比0.5、纳米Al₂O₃掺量5%(质量分数,下同)、水性环氧树脂20%、固化剂掺量2.0%。