主講人：潘偉教授【清華大學教授，博士生導師，世界陶瓷科學院院士，清華大學校務委員會委員，新型陶瓷與精細工藝國家重點實驗室主任】
時間：2018年6月20日上午10:00
地點：工學二号館202會議室
潘偉教授簡介：
潘偉，清華大學教授，博士生導師，世界陶瓷科學院院士，清華大學校務委員會委員，新型陶瓷與精細工藝國家重點實驗室主任。中國矽酸鹽學會常務理事，中國矽酸鹽學會特種陶瓷分會常務副理事長兼秘書長，國際梯度功能材料顧問委員會理事，亞洲－澳州陶瓷聯盟理事長。擔任過第六至第十九屆全國特種陶瓷學術年會秘書長、組委會主席，第一至第九屆中國國際高性能陶瓷材料學術會議組委會主席，第7屆國際梯度功能材料學術會議主席，第五屆國際陶瓷大會組委會主席。研究領域為熱障塗層陶瓷材料，透明陶瓷，電紡絲法制備納米纖維和功能器件，固态離子導體材料，輕質超硬材料、精密陶瓷部件制備技術。
報告内容簡介：
Defect Engineering in Development of Low Thermal Conductivity Materials
Wei Pan
State Key Lab of New Ceramics and Fine Processing, School of materials science and engineering,
Tsinghua University,Beijing, China
panw@mail.tsinghua.edu.cn
Increasing thermal efficiency and lower emissions require gas turbine designers to further increase the combustion temperature that leads to the high temperature components such ascombustion chambers, blade and vanes surfaces face more rigorous conditions. Therefore, there is urgent demand to develop new ceramic coatings with even lower thermal conductivity, higher stability and durability than currently used thermal barrier coatings coating on the surface of high temperature alloy components.
Defect engineering has attracted much attention in seeking better low thermal conductivitymaterials since lattice defects play a crucial role in phonon scattering and thermal conductivity reduction. Oxygen vacancies and substitutions are proven to be the most effective, while the accompanying lattice distortion is also of great importance. In thistalk, recent advances of reducing the thermal conductivity of potential thermal barrier coating materials by defect engineering are comprehensively reviewed. Effects of the mass and size mismatch between the defects and the host lattice are quantitatively estimated and unconventional thermal conductivity reduction caused by the lattice distortions is alsointroduced. Finally, challenges and potential opportunities are briefly assessed to further minimize the thermal conductivity ofthermal barrier coatings materials in the future.
In this presentation,effects of macro defects on the heat transfer in porous ceramics are also talked including the characterization method as well as modeling.
References
[1] Wan CL,W. Pan, Xu Q, Qin YX, Wang JD, Qu ZX, Fang MH, Effect of point defects on the thermal transport properties of (LaxGd1-x)2Zr2O7 : Experiment and theoretical model.Phys. Rev. B 74, 144109-1~9 (2006).
[2] Wan CL, Qu ZX, He H, Luan D,W. Pan, Ultralow thermal conductivity in highly anion-defective aluminates,Phys. Rev. Lett. 101, 085901 (2008).
[3] J. Feng, C. Wan, B. Xiao, R. Zhou, W. Pan, D. R. Clarke, Calculation of the thermal conductivity of R2SrAl2O7 (R = La, Nd, Sm, Eu, Gd, Dy),Phy. Rew. B,84, 024302 (2011)
[4] ZX Qu, Taylor Sparks, W. Pan, and David R. Clarke, Thermal conductivity of the gadolinium calcium silicate apatites: Effect of different point defect types,Acta Mater. 59 (2011) 3841–3850.
[5] CL Wan, W Zhang, YF Wang, ZX Qu, AB Du, RF Wu, W. Pan, Glasslike thermal conductivity in ytterbium doped lanthanum zirconate pyrochlore,Acta Mater. 58 (2010) 6166– 6172.
[6] XR Ren, W Pan,Mechanicalproperties ofhightemperaturedegradedyttriastabilizedzirconia,Acta Mater.69 (2014) 397–406.
[7] J. Feng, B. Xiao, R. Zhou, W. Pan, Anisotropy in elasticity and thermal conductivityof monazite-type REPO4 (RE = La, Ce, Nd, Sm, Eu and Gd) from first-principles calculations,Acta Mater. 61 (2013) 7364–7383
[8] M Zhao, W. Pan, Effect of lattice defects on thermal conductivity of Ti-doped, Y2O3-stabilized ZrO2,Acta Mater. 61 (2013) 5496–5503.
[9] CL Wan, ZX Qu, AB Du,W. Pan, Influence of B site substituent Ti on structure and thermophysical properties of A2B2O7-type pyrochlore Gd2Zr2O7,Acta Mater., 57 (2009) 4782–4789.
[10] ZX Qu, CL Wan,W. Pan, Thermophysical properties of rare-earth stannates: Effect of Pyrochlore Structure, Acta Mater. 60 (2012) 2939–294
