Polycrystalline Cr2AlC coatings were prepared on M38G superalloy using a two-step method consisting of magnetron sputtering from Cr-Al-C composite targets at room temperature and subsequent annealing at 620 ℃. Partic...Polycrystalline Cr2AlC coatings were prepared on M38G superalloy using a two-step method consisting of magnetron sputtering from Cr-Al-C composite targets at room temperature and subsequent annealing at 620 ℃. Particularly, various targets synthesized by hot pressing mixture of Cr, Al, and C powders at 650-1000 ℃ were used. It was found that regardless of the phase compositions and density of the com- posite targets, when the molar ratio of Cr：Al：C in the starting materials was 2：1：1, phase-pure crystalline Cr2AlC coatings were prepared by magnetron sputtering and post crystallization. The Cr2AIC coatings were dense and crack-free and had a duplex structure. The adhesion strength of the coating deposited on M38G superalloy from the 800 ℃ hot-pressed target and then annealed at 620 ℃ for 20 h in Ar exceeded 82 ± 6 MPa, while its hardness was 12 ± 3 GPa.展开更多
以Cr、Al、Cr3C2为原料,在700～1350℃温度范围内氩气环境下,采用无压烧结法合成Cr2AlC陶瓷粉体。研究了原料组成、烧结温度对合成Cr2AlC的影响。结果表明,原料摩尔比为1 Cr3C2/2.2Al/1Cr,温度1250℃时,样品中含有少量Cr7C3杂质,温度升...以Cr、Al、Cr3C2为原料,在700～1350℃温度范围内氩气环境下,采用无压烧结法合成Cr2AlC陶瓷粉体。研究了原料组成、烧结温度对合成Cr2AlC的影响。结果表明,原料摩尔比为1 Cr3C2/2.2Al/1Cr,温度1250℃时,样品中含有少量Cr7C3杂质,温度升高到1350℃时,获得高纯的Cr2AlC陶瓷。温度低于800℃时,Cr3C2和Al反应生成Cr2AlC和Al4C3。950℃时Cr2Al和C反应得到Cr2AlC。1350℃Cr2Al、Cr3C2和Al反应生成目标相Cr2AlC。用Kissinger方法和Owaza方法计算得到反应的表观活化能分别为362.24 k J/mol和389.01 k J/mol。展开更多
基金supported by the National Natural Science Foundation of China under Grant Nos.51271191,51571205 and 51401209
文摘Polycrystalline Cr2AlC coatings were prepared on M38G superalloy using a two-step method consisting of magnetron sputtering from Cr-Al-C composite targets at room temperature and subsequent annealing at 620 ℃. Particularly, various targets synthesized by hot pressing mixture of Cr, Al, and C powders at 650-1000 ℃ were used. It was found that regardless of the phase compositions and density of the com- posite targets, when the molar ratio of Cr：Al：C in the starting materials was 2：1：1, phase-pure crystalline Cr2AlC coatings were prepared by magnetron sputtering and post crystallization. The Cr2AIC coatings were dense and crack-free and had a duplex structure. The adhesion strength of the coating deposited on M38G superalloy from the 800 ℃ hot-pressed target and then annealed at 620 ℃ for 20 h in Ar exceeded 82 ± 6 MPa, while its hardness was 12 ± 3 GPa.
文摘以Cr、Al、Cr3C2为原料,在700～1350℃温度范围内氩气环境下,采用无压烧结法合成Cr2AlC陶瓷粉体。研究了原料组成、烧结温度对合成Cr2AlC的影响。结果表明,原料摩尔比为1 Cr3C2/2.2Al/1Cr,温度1250℃时,样品中含有少量Cr7C3杂质,温度升高到1350℃时,获得高纯的Cr2AlC陶瓷。温度低于800℃时,Cr3C2和Al反应生成Cr2AlC和Al4C3。950℃时Cr2Al和C反应得到Cr2AlC。1350℃Cr2Al、Cr3C2和Al反应生成目标相Cr2AlC。用Kissinger方法和Owaza方法计算得到反应的表观活化能分别为362.24 k J/mol和389.01 k J/mol。
