(昆明理工大學(xué) 材料科學(xué)與工程學(xué)院，昆明 650093)
摘 要: 以Ti和Al在高溫下的化學(xué)反應(yīng)熱力學(xué)條件為依據(jù)，利用激光熔覆技術(shù)在ZL117鋁活塞零件表面制備金屬間化合物TiAl3增強(qiáng)的Al基復(fù)合涂層。借助XRD、EDS和XPS分析涂層的物相組成和結(jié)構(gòu)特征，通過OM和SEM觀察涂層的表面宏觀形貌及其內(nèi)部顯微組織，運(yùn)用馬弗爐測試了熔覆涂層在靜態(tài)空氣中的高溫抗氧化性能。結(jié)果表明，復(fù)合涂層主要由淺灰色網(wǎng)狀組織TiAl3、暗灰色網(wǎng)狀間隙相α(Al)和少量晶須狀Si組成。復(fù)合涂層中Ti以TiAl3形式存在，在TiAl3中結(jié)合能分別為460.53 eV (Ti2p1峰)和454.96 eV (Ti2p3峰)；Al則以TiAl3、Al2O3和Al的形式存在，3種物相中Al的結(jié)合能分別為73.60、75.82和72.90 eV。600℃恒溫80 h下的氧化動力學(xué)曲線顯示，相同氧化條件下，涂層氧化增質(zhì)較為平緩，氧化速率小，具有較好的相對高溫抗氧化性能，相對高溫抗氧化值最大為2.64。熔覆涂層表面氧化產(chǎn)物為Al2O3和TiO2，鋁合金基體表面氧化產(chǎn)物為Al2O3和少量SiO2。
關(guān)鍵字: 激光熔覆；金屬間化合物；復(fù)合涂層；顯微組織；抗氧化
（School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China）
Abstract:In order to improve high temperature oxidation resistance of aluminum alloy, according to the chemical reaction thermodynamic conditions of Ti and Al at high temperature, TiAl3 intermetallic compound particles reinforced Al-based composite coatings were fabricated on ZL117 aluminum piston parts by laser cladding. The chemical composition, phase characteristics and microstructure of the composite coatings were analyzed using X-ray diffractometry (XRD), energy dispersive spectrum (EDS), optical microscopy (OM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The high temperature oxidation resistance of the composite coatings was tested by Muffle furnace in static air. The results show that the composite coatings are mainly composed of light gray meshwork phase TiAl3, dark gray mesh interstitial phase α(Al) and a small amount crystal whisker phase Si. Ti in the laser cladding composite coating is in the form of TiAl3 intermetallic compound, the binding energy of Ti in TiAl3 are 460.53 eV (Ti2p1 peak) and 454.96 eV (Ti2p3 peak), respectively. Al in the laser cladding composite coating is in the form of TiAl3, Al2O3 and Al, the binding energy of Al in three kinds of phases are 73.60, 75.82 and 72.90 eV, respectively. Compared with the aluminum alloy substrate, the oxidation kinetics curves at 600 ℃ for 80 h exhibit that the oxidation mass gain of the laser cladding coatings is more slowly, and the oxidation rate is low. The laser cladding coating has a good oxidation resistance at relatively high temperature and the maximum value of relatively high-temperature oxidation is 2.64. The surface oxidation products of laser cladding coatings are Al2O3 and TiO2, but the aluminum substrate surface oxidation products are Al2O3 and a small amount of SiO2.
Key words: laser cladding; intermetallic compound; composite coating; microstructure; oxidation resistance
