毛雅梅,黑鸿君,高洁,张孟,王垚,郑可,于盛旺.Ta涂层对CVD单晶金刚石焊接强度的影响[J].表面技术,2022,51(11):445-451.
MAO Ya-mei,HEI Hong-jun,GAO Jie,ZHANG Meng,WANG Yao,ZHENG Ke,YU Sheng-wang.Effect of Ta Coating on Welding Strength of CVD Single-crystal Diamond[J].Surface Technology,2022,51(11):445-451 |
| Ta涂层对CVD单晶金刚石焊接强度的影响 |
| Effect of Ta Coating on Welding Strength of CVD Single-crystal Diamond |
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| DOI：10.16490/j.cnki.issn.1001-3660.2022.11.042 |
| 中文关键词: CVD单晶金刚石 双辉等离子体表面合金化 Ta涂层 Ag–Cu–Ti钎料合金 真空钎焊 结合强度 |
| 英文关键词:CVD single-crystal diamond double glow plasma surface alloying Ta coating Ag-Cu-Ti brazing alloy vacuum brazing bonding strength |
| 基金项目:国家自然科学基金(51901154);山西省自然科学基金(201901D211092);山西省科技重大专项(20181102013);“1331项目”山西省工程研究中心资助项目(PT201801) |
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| Author | Institution |
| MAO Ya-mei | College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China |
| HEI Hong-jun | College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China |
| GAO Jie | College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;National Key Laboratory of Science and Technology on Vacuum Electronics, University of Electronic Science and Technology, Chengdu 610054, China |
| ZHANG Meng | College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China |
| WANG Yao | College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China |
| ZHENG Ke | College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China |
| YU Sheng-wang | College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China |
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| 中文摘要: |
| 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。 |
| 英文摘要: |
| The work aims to improve the weldability of diamond and facilitate the bonding between the diamond and heterogeneous alloy. Ta coating was deposited on chemical vapor deposition (CVD) single-crystal diamond (not powder or particle) surface with large-size via double glow plasma surface alloying (DGPSA) technique. Then, the Ta-coated single-crystal diamond and cemented carbide (WC-Co) were brazed with Ag-Cu-2wt.%Ti brazing alloy at 810 ℃ for 10 min in vacuum furnace. The phase composition, surface micro morphology and element distribution of Ta coating and the cross-sectional morphology after brazing were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectrum (EDS). Furthermore, to verify the effectively weldability of Ta coating for single-crystal diamond, a universal testing machine was used to conduct a shear fracture test on the brazing samples of single-crystal diamond with Ta coating and without Ta coating (control group) to explore the interfacial bonding strength after brazing. After alloying at 850 ℃, the thickness of Ta coating increased gradually from 0.35 μm to 7.96 μm for deposition of 5, 15, 30 and 60 min, the grain grew from the nano-crystal to columnar crystal, and the average grain size increased from ~84.24 nm to ~136.11 nm according to the XRD pattern and Scherrer's equation with the deposition time at the same temperature of alloying (850 ℃). The surface of Ta coating sags and crests increased with the increase of deposition time and this surface unevenly improved the flow of brazing alloy and enhanced the adhesion between Ta-coated single-crystal diamond and WC-Co during brazing. Besides, combined with the SEM of cross-sectional morphology and EDS, the Ta coating was composed of deposited layer I and diffused layer Ⅱ. This diffused layer was mainly composed of TaC and Ta2C. These two metal carbides with good mechanical properties were generated at the single-crystal diamond/Ta coating interface. The Ta2C had mechanical properties between Ta and TaC, which made it possible to improve the interface plasticity and impact resistance of single-crystal diamond/Ta coating. In addition, this carbides layer played a vital transition function at the interface between the single-crystal diamond and the Ta coating. The well bonding was provided at this interface by this layer during shearing test. After shearing test, the shear strength first increased and then decreased as the deposition time of Ta coating increased. When the deposition time is 30 min, the thickness of Ta coating is 3.47 μm. The maximum shear strength (115.6 MPa) after brazing with WC-Co is obtained, which is greater than the shear strength (75.6 MPa) of brazing samples without Ta coating. It is proved that Ta coating can obviously promote the weldability of single-crystal diamond. It is worth noting that the sample with the longest deposition time (60 min) and the largest Ta coating thickness (7.96 μm) do not have the greatest shear strength. |
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