Zirconia ceramic and Nb joints brazed with Mo-particle-reinforced Ag-Cu-Ti composite fillers: Interfacial microstructure and formation mechanism

Zirconia (ZrO₂) ceramic and Nb were successfully brazed using a Mo-particle -reinforced Ag-Cu-Ti composite filler. The effect of the Mo content of the composite filler on the interfacial microstructures and mechanical properties of ZrO₂/Nb-brazed joints was investigated. The calculated Ti activity initially increased and then decreased as the Mo content was increased from 1 to 40 wt%, and played a decisive role in the evolution of interfacial products formed adjacent to the ZrO₂ ceramic. When 40 wt% Mo particles were added to the composite filler, TiO+Ti₃Cu₃O reaction layers formed adjacent to the ceramic substrate. By decreasing the Mo content of the filler, the TiO layer became thinner or even vanished, whereas the thickness of the Ti₃Cu₃O reaction layer increased gradually with decreasing Mo content. Concurrently, a bulky TiCu compound grew near to the ZrO₂ ceramic, and further fine TiCu particles were observed in the brazing seam. This microstructure evolution, as well as the mechanism for the formation of joints brazed with composite fillers of differing Mo content, is discussed based on TEM analyses. The shear strength of the brazed joint is clearly improved when a suitable amount of Mo is added to the Ag-Cu-Ti filler. A maximum shear strength of 370 MPa was obtained when ZrO₂/Nb joints were brazed with Ag-Cu-Ti+5 wt% Mo composite filler.     

碳纳米管对Ag-Cu-Ti焊料组织与性能的影响

Ag-Cu-Ti合金作为活性焊料可以实现金属-陶瓷连接,选择碳纳米管作为添加材料,以Ag-26.7Cu-4.5Ti作为基体材料,在Ag-Cu-Ti焊料中添加碳纳米管,研究了不同含量的碳纳米管（CNTs）对Ag-Cu-Ti焊料组织和性能的影响。结果表明：添加碳纳米管可以明显降低焊料在钢基板表面的润湿铺展面积,焊料的熔化温度可以提高约9℃,显著提高焊点的抗剪切强度,当纳米管添加质量分数为0.2%时,抗剪切强度达到最大值,提高幅度达49.3%。对Ag-Cu-Ti-x CNTs(x=0, 0.05, 0.1, 0.2, 0.5, 1.0,质量分数,%,下同)焊料组织SEM分析,发现适量碳纳米管(≤0.1%)显著细化焊料基体组织,过量的碳纳米管导致焊料组织明显粗化。对Ag-Cu-Ti-x CNTs焊点断口形貌进行分析表明,Ag-Cu-Ti-x CNTs(x=0.05, 0.1, 0.2, 0.5)焊点呈现明显的韧性断裂特征,Ag-Cu-Ti和Ag-Cu-Ti-1.0CNTs焊点则表现出明显的混合断裂特征。     

Ta涂层对CVD单晶金刚石焊接强度的影响

目的 提高金刚石的可焊性,促进金刚石与异质合金的连接。方法 采用双辉等离子体表面合金化(DGPSA)技术在CVD单晶金刚石表面沉积Ta涂层,然后利用Ag–Cu–Ti(Ti的质量分数为2%)钎料合金将Ta涂层单晶金刚石与硬质合金(WC–Co)在真空钎焊炉中进行焊接。采用X射线衍射仪、扫描电子显微镜和能谱仪分析Ta涂层及焊后截面的物相组成、表面微观形貌、截面微观形貌、元素分布。使用万能试验机对有Ta涂层和无Ta涂层的焊后样品进行剪切断裂试验,对焊接后样品的界面结合强度进行探究。结果 在合金化温度为850 ℃下,随着沉积时间(5、15、30、60 min)的延长,Ta涂层的厚度从0.35 μm增至7.96 μm,晶粒由纳米晶转变为柱状晶,整个涂层由沉积层Ⅰ和扩散层Ⅱ组成,且在金刚石/Ta涂层界面处生成了2种力学性能良好的金属型碳化物,即TaC和Ta2C。焊接接头的剪切强度随着Ta涂层沉积时间的延长,呈先增大后减小的趋势。结论 当沉积时间为30 min时,Ta涂层的厚度为3.47 μm,与WC–Co焊接后其剪切强度达到最大值(115.6 MPa),且大于无Ta涂层焊接样品的剪切强度(75.6 MPa),证明Ta涂层对单晶金刚石的可焊性有明显的促进作用。     

Ag—Cu—Ti活性法封接AlN陶瓷与Mo—Cu合金

用AgCu—Ti焊料在真空条件下活性法封接了AIN陶瓷和Mo—Cu合金,用EBSD,EDS,XRD等手段分析了界面结构,对封接件进行了强度和气密性测试。结果显示：焊料中的活性组元Ti与陶瓷反应,形成厚2～3μm,紧邻陶瓷连续分布的反应层;靠近AlN一侧,焊层为AgCu共晶组织,靠近合金一侧,焊层以富Cu相为主。整个界面产物主要有TiN,Cu2Ti,AgTi3,AgTi,Ni3Ti等化合物。连接件的剪切强度στ=172．94MPa,弯曲强度στ=69．59MPa,气密性1．0×10^-11=Pa·m^3／s。     

A study of the reactive brazing of a silicon nitride to steel using ternary Ag-Cu-Ti: microstructure and mechanical strength of the bonds

A study of the behaviour of Ag-Cu-Ti braze in contact with a ceramic - its wetta bility, evolution and reactivity-by different means of investigation gives some insight into the mechanisms involved in reactive brazing. Joints between siliconnitride and a structural steel were made by brazing under various conditions of temperature, hold time and a tmosphere. The room temperature mechanical strength measured in a shear test may be correlated to some microstructural and physicochemical features. The heterogeneous microstructure observed for almost all Ag-Cu-Ti brazes is explained by immiscibility in the liquid state with an equilibrium established between Ag-Cu-rich and Cu-Ti-rich liquids. It is shown that high temperatures (> 910°C) ensure a more efficient reaction of the titanium-rich phases and so a good wetting of the siliconnitride. Consequently, the shear strengths of bonds between siliconnit ride and steel achieved by using a sufficiently high brazing temperature are optimal (123-158 MPa).     

复相A12 O3/SiCw陶瓷与不锈钢的钎焊工艺

采用氩气保护下的活性金属钎焊法对碳化硅晶须增韧氧化铝陶瓷 (Al2 O3 /SiCW)与不锈钢 (1Cr18Ni9Ti)进行了钎焊。通过对钎料润湿性的研究确定钎焊试验的温度和时间范围 ;通过剪切试验研究了钎焊工艺参数对接头强度的影响。试验结果表明 ,升高温度和增加时间均会提高钎料对陶瓷的润湿性 ,且温度超过 95 0℃后或时间超过 15min后 ,润湿角下降不明显。在氩气保护下 ,用Ag -Cu -Ti3钎料对陶瓷与不锈钢进行钎焊可以获得比较好的效果。钎焊工艺参数对接头强度影响很大 ,在钎焊温度为 90 0℃、钎焊时间为 15min时 ,钎焊接头的强度平均可达到 72MPa     

高温钎焊立方氮化硼界面微结构

以Ag-Cu-Ti合金为钎料采用真空钎焊的方法在优化的钎焊温度和时间下，实现了立方氮化硼(CBN)与砂轮基体的牢固连接。运用扫描电镜(SEM)、X射线能谱仪(EDS)及X射线粉末衍射仪(XRD)对连接界面的微观组织以及CBN表面生成物的三维形貌、化学成分、物相结构进行了综合分析。结果表明，钎料中的元素Ti向CBN表面扩散富集，生成了针状TiB2和TiN，在磨粒与钎料界面形成化学冶金结合，这是CBN与Ag-Cu-Ti钎料间有良好浸润性和高结合强度的主要原因。磨削对比试验表明钎焊CBN砂轮比电镀CBN砂轮具有更高的磨粒把持强度。     

金刚石/铜复合材料与氧化铝陶瓷的Ag-Cu-Ti活性钎焊(英文)

金刚石/铜复合材料具有低膨胀系数和高热导率等优异性能,使其成为一种理想的电子封装材料。采用97%(72Ag-28Cu)-3%Ti活性钎料对金刚石/铜复合材料和氧化铝陶瓷进行钎焊。发现活性钎料在氧化铝陶瓷和金刚石薄膜表面均具有良好的润湿性,在两者表面的平衡润湿角均小于5°。讨论了主要钎焊条件(如钎焊温度和保温时间等)对接头性能的影响。发现钎焊过程中Ti元素聚集在金刚石颗粒的表面形成TiC化合物,且TiC化合物的形貌与钎焊接头的剪切强度具有紧密联系。推测合适的TiC化合物层厚度可改善钎焊接头的剪切强度,而颗粒状的TiC化合物及过厚的TiC化合物层却会损害钎焊接头的性能。获得的最大剪切强度为117MPa。