激光内雕工艺对玻璃强度和钢化性能的影响

激光加工是一种高效环保的材料加工方法,激光内雕玻璃因具有经久耐磨、图案精美的特点,得到越来越广泛的应用.采用波长为532 nm的激光对玻璃进行内雕加工,测试分析了激光加工后玻璃内部的断口形貌、抗弯曲强度和抗冲击强度,研究了激光能量、点间距和层间距等激光加工参数对玻璃强度及后续物理钢化性能的影响.研究结果表明,当玻璃的厚度为5 mm时,在激光加工点间距设置为0.13 mm、层间距设置为0.80 mm、激光能量设置为6.5 V的条件下,玻璃的性能较好、且适合后续的物理钢化加工.     

玻璃激光内雕技术的最新进展

玻璃激光内雕技术的发展经历了传统的白色激光内雕和现代的着色激光内雕两个阶段.传统的白色激光内雕是通过在激光聚焦点的光强超过玻璃的损伤阈值而产生炸裂形成微裂纹,利用微裂纹对光的散射实现三维白色内雕.现代的着色激光内雕技术包括以下几个方面:空间选择性色心控制,离子价态操控以及纳米粒子析出.本文介绍了各种玻璃激光内雕技术的原...     

Bi_2O_3-B_2O_3-WO_3系统微晶玻璃的制备

采用熔融法制备了0.97[x Bi2O3(1-x)B2O3]·0.03WO3(0.25≤x≤O.75)基础玻璃,通过差热分析确定玻璃的特征温度,经热处理制备微晶玻璃.结果表明所制备的玻璃中只有x =0.67和x=0.60两个组成经热处理生成了微晶玻璃,颜色为乳黄色,晶相分别为BiO2和Bi2WO6,在扫描电镜下观察两种晶体的形貌均为颗粒状,晶粒尺寸在0.8～1.0μm.该体系玻璃的密度较大而硬度较小,但热处理后的微晶玻璃的密度和硬度均大于处理前的基础玻璃.     

复合晶核剂TiO2/ZrO2对MgO-Al2O3-SiO2系统微晶玻璃的影响研究

本文制备了Mg0-Al2O3-SiO2系微晶玻璃,用XRD、DTA等方法对该系统微晶玻璃材料进行了研究;讨论了复合晶核剂对材料热膨胀性能及热处理温度的影响.结果表明TiO2/ZrO2复合晶核剂中,少量ZrO2(＜0.5wt%)能够降低微晶玻璃材料的热处理温度和热膨胀系数.     

一步法热处理对复合尾矿微晶玻璃晶化过程及性能的影响

以金尾矿和铁尾矿为主要原料,采用熔融法制备了CaO-Al2O,-SiO2 (CAS)系微晶玻璃,利用差热分析(DSC)、X射线衍射分析(XRD)、扫描电镜(SEM)和综合力学性能仪等测试手段,研究了一步法热处理制度中不同温度对CAS系尾矿微晶玻璃显微结构及性能的影响.结果表明:采用一步法热处理制度可以成功制备出以透辉石(Mg0.6Fe0.2Al0.2)Ca(Si1.5Al0.5)O6为主晶相的微晶玻璃,且随着热处理温度的升高,所制备的微晶玻璃的综合性能有所提高.确定最佳的热处理制度为870℃保温2h,所制备的微晶玻璃的密度为2.97 g/cm3,抗折强度为230.33 MPa,耐酸性99.38％,耐碱性99.25％,弹性模量、剪切模量分别为118.19 GPa和47.9 GPa.     

热处理条件对硅酸盐玻璃中原位形成银纳米颗粒的影响

用离子交换结合热处理法制备银(Ag)纳米颗粒-玻璃复合材料.用透射电镜、高分辨透射电子显微镜、Ruthefford背散射谱和紫外-可见光吸收光谱研究了热处理条件对玻璃中原位形成Ag纳米颗粒的影响.结果显示:随着热处理温度升高,玻璃表面的Ag原子逐渐向玻璃内部扩散,其表面摩尔浓度逐渐降低.提高热处理温度和延长热处理时间都有利于提高玻璃中Ag纳米颗粒的体积分数.空气中,高温热处理高掺Ag量的白玻璃样品时发生二次成核,因此,Ag纳米颗粒尺寸呈双峰分布.Ag纳米颗粒尺寸的双峰分布导致其等离子体共振吸收峰出现双峰.在氢气气氛中,在250℃热处理2min,即可在玻璃中形成大量Ag纳米颗粒,颗粒尺寸小于空气中高温热处理样品的尺寸,从而引起表面等离子体共振吸收峰发生蓝移.     

利用高炉渣和粉煤灰制备微晶玻璃热处理制度的优化

以高炉渣及粉煤灰为原料,采用直接烧结法制备废渣微晶玻璃,通过正交试验研究热处理制度对微晶玻璃抗弯强度的影响.结果表明:影响微晶玻璃抗弯性能的热处理制度因素的主次顺序为晶化温度、升温速率、晶化时间和烧结时间.最佳的热处理制度参数为晶化温度970℃、晶化时间1.5h、升温速率5℃·min-、烧结温度1150℃;制备的废渣微晶玻璃主晶相为钙镁黄长石,晶粒形貌呈方块状,晶粒尺寸约2 μm;废渣利用率高,高炉渣利用率达90％,微晶玻璃性能优良.     

MgO-Al2O3-SiO2系统微晶玻璃的热处理工艺对其介电性能的影响

本文制备了MgO-Al2O3-SiO2系微晶玻璃,用XRD、DTA等方法对该系统微晶玻璃材料的析晶过程进行研究,通过正交试验,讨论了热处理温度及时间对微晶玻璃介电性能的影响.结果表明通过热处理工艺来控制晶相的析出,可以使样品的介电常数和介电损耗符合要求.获得较小介电常数的热处理制度为核化温度750℃,核化时间1h,晶化温度1100℃,晶化时间1.5h,所获得的微晶玻璃的介电常数为6.13,介电损耗4.22×10-3+可作为绝缘体等微波介质材料使用.     

CaO-MgO-Al2O3-SiO2系铜尾矿微晶玻璃析晶特征研究

以铜尾矿为主要原料,采用压延法开展玻璃熔制实验制备CMAS系基础玻璃,进行玻璃微晶化及稳定性等方面的研究.利用差热分析(DSC)、X衍射分析(XRD)、扫描电镜(SEM)等方法系统研究了微晶玻璃组分、热处理温度和时间等因素对玻璃析晶的影响.完成了以透辉石(Ca(Mg,Al)(Si,Al)2 O6)为主晶相的微晶玻璃制品实验配方及制备工艺方案,确定了热处理制度为900℃保温2 h的最佳工艺参数,制备的微晶玻璃力学性能优于市场同类产品.     

热处理工艺对高炉矿渣微晶玻璃性能的影响

以某高炉矿渣为主要原料,采用熔融法制备了CaO-Al_2O_3-SiO_2系矿渣微晶玻璃。研究了热处理工艺对矿渣微晶玻璃力学性能的影响,得出热处理工艺影响因素的先后顺序为:核化温度-核化时间-晶化时间-晶化温度,确定最佳热处理工艺为:770℃核化3 h,930℃晶化2 h,在此热工艺条件下制备的微晶玻璃抗弯强度最大,为153.67 MPa。利用X射线衍射(XRD)、扫描电镜(SEM)、能谱(EDS)测试方法分析了矿渣微晶玻璃的显微结构和晶体微观结构。     

多波段激光防护PMMA材料的制备

以聚甲基丙烯酸甲酯(PMMA)为基材．在基材中加入防激光吸收剂IR530、IR1065，制备了能有效吸收488nm、514nm、530nm、1060nm等多个波长激光的PMMA材料。通过实验研究确定了防激光吸收剂IR530、IR1065的加入量和激光防护PMMA材料的制备工艺参数。结果表明，多波段激光防护PMMA材料在488nm、514nm、530nm处的透过率为0．01％，在1060nm处的透过率为0．02％，具有良好的激光防护性能。同时防激光吸收剂的加入对材料的冲击强度影响很小。     

Effect of laser scanning speed on geometrical features of Nd:YAG laser machined holes in thin silicon nitride substrate

0.5 mm thick Silicon nitride (Si₃N₄) substrates with MgO-Y₂O₃ additives were employed for hole machining study with a Nd:YAG two-dimensional laser machining (cutting) system. The effects of laser scanning speed on features of the machined holes such as hole diameter, hole circularity, taper angle, heat affected zone (HAZ), recast layer, and micro-cracks were studied. The results show that the diameters at the front side are larger than the back side for all holes machined at different spot scanning speed. The taper angle of the machined holes decreases, while the hole circularity increases with the increase of the spot scanning speed. In addition, the heat-affected-zone (HAZ) was observed clearly around the back side of drilled holes, whose area decreases with the increase of the laser spot scanning speed. The result shows that the HAZ is the largest when the laser scanning speed is 20 mm/min. Nevertheless, the machined hole did not completely cross through the thickness of the substrate when the laser scanning speed was 60 mm/min. To obtain holes with relatively good quality, laser scanning speed should be controlled between 30 mm/min and 50 mm/min.     

Laser stealth and laser protection properties of oxide-carbide coatings prepared by atmospheric plasma spraying

With the development of laser technology, laser-related materials have been widely studied. Both laser stealth coatings and laser protective coatings are currently the focus of attention. However, less research has been done on laser stealth and protective integrated coatings. In this paper, plasma-sprayed Y₂O₃–Ti₃AlC₂ coatings were prepared with low-power (LP) and high-power (HP) parameters, and their laser stealth and laser protection properties were characterized. The LP coating and HP coating appeared to have lower reflectivity at 1064 nm because a low-reflectivity second phase and many loose flocs on the surface are introduced, which indicates excellent laser stealth performance. When irradiated by a laser, the LP coating exhibited excellent laser protection ability, and its reflectivity increased after irradiation because Ti₃AlC₂ oxidized and decomposed and densely arranged small particles formed on the surface. The LP coating perfectly protected the 500-W laser irradiation for 20 s. In addition, the laser damage threshold of the LP coating was 5.599 s at 1000-W laser irradiation, which indicates that the LP Y₂O₃–Ti₃AlC₂ coating is a potential material with laser stealth and laser protection integration.     

三维激光全息打印机的研制与发展

最近,关于数字激光全息技术、数字衍射光学元件的制造技术与设备的研究比较活跃.激光全息打印是在数控激光全息技术薄膜材料上打印出富有立体感的、动态的、彩色的文字和图像,其中,三维激光全息打印机是比较新的一个产品.本文正是对三维激光全息打印机的研制和发展做出探讨,了解这项新技术.     

Effects of reflectivity on laser-ablation resistance of the laser-cladding repaired Nd2O3 modified SiO2 coatings on C/C composites

To repair the damaged SiC coated C/C composites, a double-layer coating including a SiO₂-Nd₂O₃ external layer (∼60 μm) and a Si-SiC inner layer (∼240 μm) was prepared by a slurry-based laser cladding technique, and the laser-ablation tests under two heat fluxes (23.89/39.81 MW m⁻²) were performed. The spectrophotometer, X-ray diffraction, scanning electron microscopy and 3D profilometer were used for characterization. For avoiding the secondary damage of laser-ablation, the laser-reflection of the repaired area was enhanced, which was conducive to the mitigation of mass and linear ablation. Combined with Finite Element Analysis, by raising the reflectivity, the surface and back temperature of samples could be reduced greatly by 1224 K and 983 K respectively, and plenty of ablation reactions could be avoided. Therefore, the SiO₂-Nd₂O₃ coating possessed an excellent laser-ablation resistance and protected the C/C substrates from thermal damage and oxidation effectively.     

IR laser-induced modification of poly(vinyl acetate): Elimination of monomer and deposition of polar crosslinked films

IR laser-induced modification of poly(vinyl acetate) (PVAC) was examined through ablative and non-ablative thermal processing of bulk PVAC. Both laser-induced processes differ remarkably from conventional heating of PVAC, which yields acetic acid and non-polar carbonaceous residue. The non-ablative treatment at low-fluence irradiations results in the formation of volatile vinyl acetate and acetone and leaves the remaining irradiated polymer having an almost identical structure. The ablative treatment at high-fluence irradiations yields a multitude of volatile compounds (methane, ethane, vinyl acetate, acetone, acetic acid, benzene, H₂, CO and CO₂) and affords deposition of thin polymeric films that contain reactive conjugated CC bonds and half of the initially present acetate groups. Residual reactivity of the CC bonds leads to polymer crosslinking, substantial decrease in solubility and some increase in thermal stability. The low fluence-induced decomposition stands for the first example of the thermal decomposition of polyvinyls into the monomer and the high-fluence ablative deposition represents a one-step approach to crosslinked (intractable), thermally stable and polar polymeric films from linear-chain polymers with pending functional groups.     

On the shear strength of laser brazed SiC–steel joints: Effects of braze metal fillers and surface patterning

Within the development of a laser brazing process for joining non-oxide ceramics (SiC) to steel, we examined the effect of different braze filler metals on the shear strength of the joint. Specific surface patterns were applied on the surface of the ceramic in order to study changes of the joint strength by an additional mechanical anchoring at the ceramic–braze metal interface.     

PVC异型材原料粒径分布测试方法的评价

本文介绍了三种PVC异型材原料粒径分布的测试方法:沉降法(检测时间长,重现性差)、筛分法(操作复杂)、激光法(准确方便)。     

Progress and perspectives on composite laser ceramics: A review

Solid-state laser has been widely used in industrial production, military weapons and scientific research because of its compact structure, convenient use and high output power. As the core material of solid-state laser, gain media are the key to its further development. Therefore, the design of appropriate composite structure gain media has attracted extensive attention. Especially for laser ceramics with excellent structural designability, the research on their composite structures has developed rapidly, such as surface gain structure that can improve thermal conductivity; concentration gradient doping structure that can improve energy storage capacity and temperature gradient; clad-core structure which can suppress ASE effect and optical waveguide structure which can improve thermal effect and facilitate device miniaturization. In this paper, the structure design, materials preparation and performance advantages of different composite laser ceramics have been introduced systematically. Finally, the progress of composite laser ceramics is summarized, and the prospect is put forward.     

Nanofabrication with Pulsed Lasers

An overview of pulsed laser-assisted methods for nanofabrication, which are currently developed in our Institute (LP3), is presented. The methods compass a variety of possibilities for material nanostructuring offered by laser–matter interactions and imply either the nanostructuring of the laser-illuminated surface itself, as in cases of direct laser ablation or laser plasma-assisted treatment of semiconductors to form light-absorbing and light-emitting nano-architectures, as well as periodic nanoarrays, or laser-assisted production of nanoclusters and their controlled growth in gaseous or liquid medium to form nanostructured films or colloidal nanoparticles. Nanomaterials synthesized by laser-assisted methods have a variety of unique properties, not reproducible by any other route, and are of importance for photovoltaics, optoelectronics, biological sensing, imaging and therapeutics.