本文選題：SiC陶瓷 + 超聲輔助釬焊��； 參考：《哈爾濱工業(yè)大學(xué)》2017年碩士論文

【摘要】：碳化硅(SiC)陶瓷,由于其具有熱膨脹系數(shù)小,抗氧化性強(qiáng),熱導(dǎo)率大,耐磨性能好,熱穩(wěn)定性好等優(yōu)良特性,是制作封裝基板的重要材料。SiC陶瓷共價鍵性非常強(qiáng),難以被液態(tài)金屬潤濕。本文采用超聲波輔助釬焊的方式,使用Sn-3.5Ag-4Ti和Sn-3.5Ag-4Al活性釬料實(shí)現(xiàn)了SiC陶瓷在大氣環(huán)境下的低溫釬焊,深入研究了兩種活性釬料在連接SiC陶瓷時,超聲釬焊工藝、界面微觀組織結(jié)構(gòu)和界面結(jié)合機(jī)制的特點(diǎn),在此基礎(chǔ)上對超聲波快速釬焊工藝進(jìn)行了探索。使用Sn-Ag-Ti在250℃時超聲釬焊SiC陶瓷,接頭的剪切強(qiáng)度隨超聲波作用時間的延長呈上升趨勢,超聲6s時接頭強(qiáng)度達(dá)到最大,約為49MPa左右。不同超聲時間下,SiC/Sn-Ag-Ti界面未發(fā)現(xiàn)明顯的差異。SiC/Sn-Ag-Ti界面平直,沒有發(fā)現(xiàn)裂紋、孔洞或者雜質(zhì)等缺陷的存在,接頭連接良好。在超聲波的作用下,Ti向界面擴(kuò)散并產(chǎn)生富集現(xiàn)象,Ti與非晶SiO2發(fā)生反應(yīng)生成TiO和單質(zhì)Si。初始階段界面反應(yīng)由不充分,Ti與非晶SiO2反應(yīng)生成不連續(xù)的非晶TiO,延長超聲時間非晶SiO2與Ti充分反應(yīng)生成連續(xù)的TiO。使用Sn-Ag-Al在250℃時超聲釬焊SiC陶瓷,接頭的剪切強(qiáng)度隨超聲波作用時間的延長呈上升趨勢,超聲20s時接頭強(qiáng)度值達(dá)到最大,約為50MPa左右。不同超聲時間,SiC/Sn-Ag-Al界面未發(fā)現(xiàn)明顯的差異。SiC/Sn-Ag-Al界面平直,沒有發(fā)現(xiàn)裂紋、孔洞或者雜質(zhì)等缺陷的存在,接頭連接良好。在超聲波的作用下,Al向固-液界面擴(kuò)散并產(chǎn)生富集現(xiàn)象,Al與非晶SiO2發(fā)生反應(yīng)生成非晶Al2O3和單質(zhì)Si。超聲時間延長,界面反應(yīng)由不充分到充分,非晶SiO2上層首先與Al反應(yīng),延長超聲時間非晶SiO2與Al完全反應(yīng)。SiC陶瓷接頭的強(qiáng)度與界面反應(yīng)的進(jìn)行程度有關(guān),且Ti元素的活性大于Al元素。隨著涂覆時間延長,SiC陶瓷表面生成的TiO增多,接頭強(qiáng)度呈上升趨勢。涂覆時間50s,超聲釬焊0.1s時接頭強(qiáng)度達(dá)到母材強(qiáng)度,約為50MPa左右。
[Abstract]:Because of its small thermal expansion coefficient, strong oxidation resistance, high thermal conductivity, good wear resistance and good thermal stability, sic ceramic is an important material for making packaging substrate. It is difficult to be wetted by liquid metal. In this paper, ultrasonic assisted brazing is used to realize the low temperature brazing of SiC ceramics in atmospheric environment by using Sn-3.5Ag-4Ti and Sn-3.5Ag-4Al active solders. The ultrasonic brazing process of the two active solders joining SiC ceramics is studied in depth. On the basis of the characteristics of interface microstructure and interface bonding mechanism, ultrasonic rapid brazing process was explored. The shear strength of SiC ceramics brazed with Sn-Ag-Ti at 250 鈩，

本文編號：1867545