【摘要】：可降解材料因具有制備簡單、易加工成形且環(huán)境污染小等優(yōu)點在能源開發(fā)和油氣開采領(lǐng)域應(yīng)用廣泛,而可降解高分子材料和生物陶瓷由于無法承受高溫高壓、易變形、降解環(huán)境苛刻等缺點不能滿足使用要求。相比于可降解高分子和陶瓷材料,可降解金屬作為一種新材料,因來源豐富、成本低、適應(yīng)性強、機械性能和導(dǎo)電導(dǎo)熱性良好等優(yōu)點具有巨大應(yīng)用空間而深受關(guān)注。但目前可降解金屬存在結(jié)構(gòu)單一,降解穩(wěn)定性差等缺點制約其在油氣開采領(lǐng)域廣泛應(yīng)用。本論文采用熔鑄法在鋁中添加合金元素Ga、In和Sn制備綜合性能良好的Al基可降解金屬材料。本論文采用熔鑄法成功制備了用于油氣壓裂用的可降解Al合金,通過X射線衍射(XRD)、掃描電鏡(SEM)及能譜分析(EDS)等測試手段詳細研究了Sn、Ga和In等合金元素及熱處理工藝對該合金組織和相關(guān)性能的影響。并結(jié)合電化學(xué)極化曲線和腐蝕形貌分析對該Al基合金腐蝕行為及相關(guān)機理進行了探討。以Al-Mg合金為基體,添加元素Sn且隨著Sn含量的增加,該合金中出現(xiàn)了Mg2Sn第二相及少量Sn單質(zhì),合金基體得到了明顯細化,腐蝕電位明顯負移,但該合金降解性能較差。在12 wt.% Sn含量基礎(chǔ)上,進一步引入3 wt.%的元素Ga時,合金的腐蝕電位進一步負移,在90℃水中具有較高的降解速度,90 min內(nèi)其質(zhì)量減少了50%。為了降低該合金的可降解溫度,在Al-Mg-Ga-Sn基礎(chǔ)上添加不同含量的元素In。電化學(xué)測試表明,隨著In含量的增加,合金微觀組織一定程度細化,其腐蝕電位更負,降解速率不斷提高。當(dāng)In添加量為1.3 wt.%時,在90℃的水中,75 min內(nèi)質(zhì)量減少了50%,相比未添加In提高了16.7%；在70℃水中,該合金95 min內(nèi)質(zhì)量減少了50%。在此基礎(chǔ)上,進一步研究了In和Sn配比對該合金微觀組織和性能的影響,隨Sn比例提高,合金中Ga-In-Sn共熔體體積逐漸增大,并由顆粒狀轉(zhuǎn)變?yōu)榘魻�；但電化學(xué)極化曲線表明該合金腐蝕電位正移,活性降低,但當(dāng)減小Sn的配比時,共熔體體積逐漸減小,腐蝕電位負移,當(dāng)Ga:In:Sn分別為9：6：4和15：3.5：30時,所制備的Al基合金降解溫度得到進一步降低,在50℃水中的分別在440 min和470 min內(nèi)質(zhì)量減少了50%。對該合金的熱處理結(jié)果表明,保溫時間相同,熱處理溫度從300℃升高到500℃時,鋁基體晶粒從40～50 μm增長到70～80 μm。同時,第二相含量明顯減小,分布更加均勻,極化曲線表明其腐蝕電位略微負移,活性增大；在300℃下延長保溫時間,極化曲線表明合金腐蝕電位負移,降解活性增大,在50℃水中反應(yīng)速率明顯大于鑄態(tài)；在500℃下隨保溫時間延長,第二相Mg2Sn由棒狀變?yōu)榍蛐?電化學(xué)測試表明合金的腐蝕電位正移,活性降低,原因為球形的合金相與基體接觸面積減小。通過極化曲線和腐蝕微觀形貌對該Al基可降解合金腐蝕行為分析表明：腐蝕過程中,Mg2Sn合金相作陰極,Al基體作陽極,腐蝕反應(yīng)從Mg2Sn合金相周圍以點蝕開始,點蝕在基體表面擴展導(dǎo)致了合金最后的均勻腐蝕。
[Abstract]:The degradable material has the advantages of simple preparation, easy processing and forming, low environmental pollution and the like, the disadvantages of severe degradation environment and the like can not meet the use requirement. Compared with degradable high polymer and ceramic material, degradable metal as a new material has great application space because of abundant source, low cost, strong adaptability, good mechanical property and good conductive thermal conductivity. However, the existing degradable metal has the disadvantages of single structure, poor degradation stability and the like, and is widely applied in the field of oil and gas exploitation. In this paper, Al-based degradable metal materials with good comprehensive properties are prepared by adding alloy elements Ga, In and Sn in Al. The degradable Al alloy for oil and gas fracturing was successfully prepared by casting method, and Sn was studied by XRD, SEM and EDS. Effect of alloying elements of Ga and In and heat treatment on microstructure and related properties of the alloy. The corrosion behavior and related mechanism of Al-based alloy were discussed in combination with electrochemical corrosion resistance and corrosion morphology analysis. With Al-Mg alloy as matrix, element Sn was added and with the increase of Sn content, the second phase of Mg2Sn and a small amount of Sn simple substance appeared in the alloy, the alloy matrix was obviously refined, and the corrosion potential was obviously negative, but the degradation performance of the alloy was poor. at 12 wt. On the basis of the% Sn content, 3 wt.% was further introduced. When the element Ga is%, the corrosion potential of the alloy is further shifted, the degradation rate is higher in 90 鈩，

本文編號：2273510