%0 Journal Article %1 Gallet2006 %A Gallet, S. Le %A Rebillat, F. %A Guette, A. %A Naslain, R. %D 2006 %J High Temperature Ceramic Matrix Composites %K BCl3-NH3-H2 BN air; ambient ceramic coatings composites; from gas high in matrix mixtures; stability temperature %R 10.1002/3527605622.ch30 %T Stability in Air at Ambient Temperature of BN Coatings Processed from BCl$_3$-NH$_3$-H$_2$ Gas Mixtures %X Generally, BN coatings processed from BCl3-NH3-H2 gas mixtures display a poor degree of crystallisation under commonly used CVD/CVI conditions (low pressure and temperature). The crystallisation of these coatings requires a post-deposition heat treatment. Some authors 1,2 have noticed the poor stability of as-processed coatings, at ambient temperature. The BN stability must be improved to limit the ageing of the interphase in CMCs at ambient temperature and therefore to maintain the properties of the composites at high temperatures 3. Furthermore, the presence of oxygen within the as-processed coatings influences the crystallisation behaviour of BN during heat treatment 2. The stability in air at ambient temperature of the coatings before and after heat treatment was studied through: (i) the weight gain as a function of time (from few days to 2 months), (ii) the quantity of oxygen or moisture absorbed (as measured by AES) and (iii) the characterisation of new compounds formed at the surface of the coatings by XRD. The oxidation resistance and the crystallisation degree of the aged coatings before and after heat treatment were related to the quantity of oxygen absorbed.

@article{Gallet2006, abstract = {Generally, BN coatings processed from BCl3-NH3-H2 gas mixtures display a poor degree of crystallisation under commonly used CVD/CVI conditions (low pressure and temperature). The crystallisation of these coatings requires a post-deposition heat treatment. Some authors [1,2] have noticed the poor stability of as-processed coatings, at ambient temperature. The BN stability must be improved to limit the ageing of the interphase in CMCs at ambient temperature and therefore to maintain the properties of the composites at high temperatures [3]. Furthermore, the presence of oxygen within the as-processed coatings influences the crystallisation behaviour of BN during heat treatment [2]. The stability in air at ambient temperature of the coatings before and after heat treatment was studied through: (i) the weight gain as a function of time (from few days to 2 months), (ii) the quantity of oxygen or moisture absorbed (as measured by AES) and (iii) the characterisation of new compounds formed at the surface of the coatings by XRD. The oxidation resistance and the crystallisation degree of the aged coatings before and after heat treatment were related to the quantity of oxygen absorbed.}, added-at = {2009-11-05T12:01:24.000+0100}, author = {Gallet, S. Le and Rebillat, F. and Guette, A. and Naslain, R.}, biburl = {https://www.bibsonomy.org/bibtex/2078f9ba52f9fbb4eef5679ba5553ba31/ghuot}, doi = {10.1002/3527605622.ch30}, interhash = {cd949a0130f65b92e0e5fca4f825c529}, intrahash = {078f9ba52f9fbb4eef5679ba5553ba31}, journal = {High Temperature Ceramic Matrix Composites}, keywords = {BCl3-NH3-H2 BN air; ambient ceramic coatings composites; from gas high in matrix mixtures; stability temperature}, owner = {Guillaume}, timestamp = {2009-11-05T12:01:28.000+0100}, title = {Stability in Air at Ambient Temperature of BN Coatings Processed from BCl$_{3}$-NH$_{3}$-H$_{2}$ Gas Mixtures}, year = 2006 }