Hostname: page-component-7bb8b95d7b-fmk2r Total loading time: 0 Render date: 2024-09-12T13:34:58.275Z Has data issue: false hasContentIssue false
  • English
  • Français

Compositionally graded mullite-based chemical vapor deposited coatings

Published online by Cambridge University Press:  31 January 2011

Tushar Kulkarni ,
H.Z. Wang ,
S.N. Basu  and
V.K. Sarin
Tushar Kulkarni*
Affiliation:
Division of Materials Science and Engineering, Boston University, Brookline, Massachusetts 02446
H.Z. Wang
Affiliation:
Division of Materials Science and Engineering, Boston University, Brookline, Massachusetts 02446; and Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467
V.K. Sarin
Affiliation:
Division of Materials Science and Engineering, Boston University, Brookline, Massachusetts 02446; and Department of Mechanical Engineering, Boston University, Boston, Massachusetts 02215
*
a) Address all correspondence to this author. e-mail: tushark@bu.edu
Get access

Abstract

Dense, crystalline mullite (3Al2O3ċ2SiO2) coatings have been deposited by chemical vapor deposition on Si-based substrates using the AlCl3–SiCl4–CO2–H2 system. A graded coating composition has been achieved in the coatings, with the Al/Si ratio being stoichiometric (∼3) at the coating/substrate interface, and increasing monotonically toward the outer coating surface. The highest reported Al-rich mullite has been deposited in the process. At high Al/Si ratios, the mullite structure breaks down and an aluminosilicate phase similar to the metastable δ* Al2O3 is nucleated. Experimental evidence is presented in this study that this phase has some Si-incorporation in it and has been called δ*(Si)Al2O3. Like the other known aluminosilicates, δ*(Si)Al2O3 converts to mullite on heating at elevated temperatures.

Keywords

CeramicChemical vapor deposition (CVD) (deposition)Coating
Type
Articles
Information
Journal of Materials Research , Volume 24 , Issue 2 , February 2009 , pp. 470 - 474
Copyright
Copyright © Materials Research Society 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Shepherd, E.S., Rankin, G.A., Wright, W.: The binary systems of alumina with silica, lime and magnesia. Am. J. Sci. 28, 293 (1909)Google Scholar
2.Bowen, N.L., Greig, J.W.: The system Al2O3 SiO2. J. Am. Ceram. Soc. 7, 238 (1924)Google Scholar
3.Basu, S.N., Kulkarni, T., Wang, H.Z., Sarin, V.K.: Functionally graded chemical vapor deposited environmental barrier coatings for Si-based ceramics. J. Eur. Ceram. Soc. 28, (2)437 (2008)Google Scholar
4.Kulkarni, T., Basu, S.N., Sarin, V.K.: Advanced environmental barrier coatings. Key Eng. Mater. 333, 59 (2007)Google Scholar
5.Mulpuri, R.P., Sarin, V.K.: Synthesis of mullite coatings by chemical vapor deposition. J. Mater. Res. 11, 1315 (1996)CrossRefGoogle Scholar
6.Auger, M.L., Sarin, V.K.: The development of CVD mullite coatings for high temperature corrosive applications. Surf. Coat. Technol. 94–95, 46 (1997)CrossRefGoogle Scholar
7.Cameron, W.E.: A substituted alumina. Am. Mineral. 62, 747 (1977)Google Scholar
8.Schneider, H., Komarneni, S.: Mullite(WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Germany 2005)61Google Scholar
9.Burnham, C.W.: Composition limits of mullite, and the sillimanite mullite solid solution problem. Carnegie Inst. Washington Year Book 63, 227 (1964)Google Scholar
10.Fischer, R.X., Schneider, S., Schmucker, M.: Crystal structure of Al-rich mullite. Am. Mineral. 79, 983 (1994)Google Scholar
11.Mulpuri, R.P., Sarin, V.K.: Chemical vapor deposition of mullite coatings. U.S. Patent No. 576008 (June 9,1998)Google Scholar
12.Auger, M.L., Sarin, V.K.: A kinetic investigation of CVD mullite coatings on silicon based substrates. Int. J. Refract. Met. Hard Mater. 19, 479 (2001)Google Scholar
13.Hou, P., Basu, S.N., Sarin, V.K.: Nucleation mechanisms in chemically vapor deposited mullite coatings on SiC. J. Mater. Res. 14, 2952 (1999)Google Scholar
14.Wang, H.Z., Kulkarni, T., Basu, S.N., Sarin, V.K.: Ordered and twinned multidomain structure in highly Al-rich mullite. J. Mater. Res. 22, 3211 (2007)Google Scholar
15.Argeot, D., Mercurio, D., Dauger, A.: Structural characterization of alumina metastable phase in plasma sprayed deposits. Mater. Chem. Phys. 24, 299 (1990)CrossRefGoogle Scholar
16.Doppalapudi, D.: Development of CVD mullite coatings for Si-based ceramics. MS Thesis Boston University Boston, MA 1995Google Scholar
17.Schneider, H., Majdic, A.: Kinetics of the thermal decomposition of kyanite. Ceramurgia Int. 6, 32 (1981)Google Scholar
18.Schneider, H., Majdic, A.: Kinetics and mechanism of the solid-state high temperature transformation of andalusite (Al2SiO5) into 3/2 mullite (3Al2O3.2SiO2) and silica (SiO2). Ceramurgia Int. 5, 31 (1979)CrossRefGoogle Scholar
19.Schneider, H., Majdic, A.: Preliminary investigations on the kinetics of the high temperature transformation of sillimanite to 3/2 mullite plus silica and comparison with the behavior of andalusite and kyanite. Sci. Ceram. 11, 191 (1981)Google Scholar
20.Oliver, W.C., Pharr, G.M.: An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J. Mater. Res. 7, 1564 (1992)Google Scholar
21.Saif, M.T.A., Zhang, S., Haque, A., Hsia, K.J.: Effect of native Al2O3 on the elastic modulus of thin Al films. Acta Mater. 50, 2779 (2002)CrossRefGoogle Scholar
22.Ledbetter, H., Kim, S., Balzar, D., Crudele, S., Kriven, W.: Elastic properties of mullite. J. Am. Ceram. Soc. 81, 1025 (1998)Google Scholar