- Email: [email protected]
Studies on composite coatings prepared by plasma spraying Fe2O3–Al self-reaction composite powders
Surface and Coatings Technology 179 (2004) 223–228
Studies on composite coatings prepared by plasma spraying Fe2O3 –Al self-reaction composite powders Yanchun Dong*, Dianran Yan, Jining He, Xiangzhi Li, Wenran Feng, Hai Liu School of Material Science and Engineering, Hebei University of Technology, Tianjin 300130, PR China Received 13 January 2003; accepted in revised form 5 June 2003
Abstract Fe2O3 –Al composite powders were prepared using ferric oxide agent powders, aluminum powders and polyvinyl alcohol. Selfreaction composite coatings containing ceramic and metal multi-phases were fabricated by plasma spraying Fe2 O3 –Al composite powders. This technology successfully combines self-propagating high-temperature synthesis with plasma spraying. The morphology of the composite powders was examined by scanning electron microscope (SEM). The chemical composition, microstructure, Vickers hardness, density, porosity and wear resistance of the composite coating were studied. The wear resistance of the ceramic and metal multi-phase composite coating was significantly improved under heavy load. 䊚 2003 Elsevier B.V. All rights reserved. Keywords: Plasma spraying; Self-reaction; Ceramic coating; Composite coating
1. Introduction Self-propagating high-temperature synthesis or combustion synthesis (denoted as SHS) is a fairly simple technology with a high reaction temperature. It is difficult to control the reaction of SHS w1,2x because the process of SHS is very fast. The density of the material prepared by SHS is so low that the wear resistance and corrosion resistance of the coating is reduced w3–5x. It is noticeable that SHS cannot synthesise coatings on the surface of the axle or plane. For plasma spray, plasma efflux has the higher temperature (above 10 000 K) w6,7x and the higher velocity, which can almost melt all kinds of solid materials w8x. The density of plasma sprayed coatings is higher than that of coatings sprayed by other methods w9x. Polyvinyl alcohol was used to bind Al and Fe2O3 composite powders. Multi-phases self-reaction (denoted as MPSR) composite coating possessing excellent mechanical properties can be prepared by spraying these composite powders that can react in the plasma efflux. It is possible to prepare sintered composite coatings with the low power equipment. MPSR composite coating can also be made on *Corresponding author. Tel.: q86-22-2656-4581; fax: q86-222656-4774. E-mail address: [email protected] (Y. Dong).
surfaces of the axle and plane. The metal phase in the MPSR composite coating can improve the toughness of the MPSR composite coating. 2. Experiment 2.1. Experimental procedure The raw powders used in making composite powders were commercially available Fe2O3 and Al powders according to Fe2O3q2Als2FeqAl2 O3 q836 kJ. The sizes of Fe2O3 and Al particles are 30 mm and 50 mm, respectively. The polyvinyl alcohol was used as binder to bind Fe2O3 and Al powders together. The preparing process of composite powders was as follows: First, Fe2O3 and Al powders were thoroughly mixed for 24 h in a grinding machine. Secondly, the compounded powders were mixed again with polyvinyl alcohol solution. Thirdly, the compound was dried in an oven under 150 8C, shattered in a grinding machine and sifted through y80 and y120 mesh sifters. 2.2. Fabrication of the MPSR coating Samples of 30=25=10 mm were cut from a low carbon steel roller. Prior to spraying the MPSR composite coating, all the samples were sand-blasted to get
0257-8972/04/$ - see front matter 䊚 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0257-8972(03)00815-6
224
Y. Dong et al. / Surface and Coatings Technology 179 (2004) 223–228
Fig. 1. The SEM image of composite powders.
rough surfaces. Ni-10 wt.%Al self-melting alloy bond layer with a thickness of approximately 0.1 mm was sprayed onto surfaces of the samples to increase the adhesive strength of the MPSR composite coating and the steel substrate. The coating was sprayed by means of GDP-2 type plasma spraying device, whose power is 50 kW, made by JiuJiang Spraying Device Company China, the spraying gun was self-designed and made. The Fe2O3 –Al composite powders were ignited by the plasma flame and reacted. 2.3. Measurement of the MPSR composite coating properties The morphology of composite powders and MPSR composite coatings were observed by means of XL30y TMP scanning electron microscope (SEM). The X’PertMPD X-ray diffraction instrument was adopted to analyse the phases composition of MPSR composite coating. Measurement of the opening porosity of coatings was carried out by Archimede’s method, referring to the industry standard of commonwealth Germany ‘DIN51056’ w10x. Vickers hardness of the coatings was measured by using the digital Vickers hardness tester made in Shanghai Taiming Optical Instrument Co. Ltd., China. A load weight 100 g was applied to perform the indentation and maintained for 15 s. Sliding wear test was carried out on the MM-200 wear test machine made in Xuanhua Material Test Machine Co. Ltd., China, with a sliding speed of 0.4;0.8 mys. The wear resistance of the MPSR coating was denoted with the volume loss, compared with a Ni-15Cr-3.5B-4.0Si-10Fe (Ni–Cr–B– Si) alloy coating and a pure Al2O3 ceramic coating. The distance of friction was 18 km under 0;2000 N load.
3. Experimental results and discussion 3.1. Morphology of composite powders The morphology of self-made Fe2O3 –Al composite powders is shown in Fig. 1. It can be seen from Fig. 1 that the surfaces of all Al particles were partly or completely enwrapped by Fe2O3 particles. It was found through experiments that approximately 90% Al particles’ surfaces were completely enwrapped by the Fe2O3 particles. Most composite powders are fit for the reaction of Fe2O3q2Als2FeqAl2O3, according to the reaction equation, superfluous Al or Fe2O3 powders attributing to partly enwrapped result in intermediate reaction productions FeAl2O4, FeAl and Fe3Al appeared in MPSR composite coating. 3.2. Microstructural characterization of the MPSR composite coating Fig. 2 shows the SEM microstructure of the MPSR coating and Fig. 3 gives the energy-dispersive spectrum analysis of corresponding phases in Fig. 2. It is shown that four phases appear in the MPSR composite coating. The light phase (zone A) in Fig. 2 is metal Fe, whose spectrum is shown in Fig. 3a, the light grey phase (zone B) shown in Fig. 2 is alloy FeAl, whose spectrum is shown in Fig. 3b, the dark phase (zone C, E) is Al2O3 ceramic shown in Fig. 3c and e, the grey phase (zone D) is FeAl2O4 spinel. Fig. 4 shows the X-ray diffraction patterns of the MPSR composite coating. It is found that the MPSR coating consists of Al2O3, FeAl2O4, metal Fe, FeAl and Fe3Al, which indicates that Al and Fe2O3 in the composite powders have completely reacted. The FeAl2O4 phase came from the chemical equation Al2O3qFeOs
Y. Dong et al. / Surface and Coatings Technology 179 (2004) 223–228
225
Fig. 2. SEM image of the MPSR composite coating.
FeAl2O4, FeO coming from the Fe2O3 reduced w11x. FeAl and Fe3Al came from contiguous Fe and Al melted. It can be seen from Figs. 4 and 2 that Al2O3 ceramic and FeAl2O4 spinel phases form the structure frame of
the MPSR composite coating. Fe, FeAl and Fe3Al are the second phases. It is well known that the Al2O3 ceramic and FeAl2O4 spinel are hard and brittle phases, metal Fe possessed high toughness. As a result, the
Fig. 3. The energy-dispersive spectrums of the MPSR coating.
226
Y. Dong et al. / Surface and Coatings Technology 179 (2004) 223–228
Fig. 3 The energy spectrum of MPSR coatings.
coexistence of metal phases and ceramic phases can effectively improve the toughness of the coating. 3.3. Vickers hardness, porosity and density of the MPSR composite coating The Vickers hardness of different phases of the MPSR composite coating is listed in Table 1. It can be known
from Table 1 that the Vickers hardness of Al2O3 ceramic is 1310HV0.1. The Vickers hardness of FeAl2O4 spinel is lower than that of Al2O3. The Vickers hardness of the metal and alloy is the lowest among the phases, only 252HV0.1. Stress concentration and fine cracks easily form in the hard and brittle Al2O3 ceramic when the MPSR composite coating sustains impact and stress. Metal and alloy, which have excellent toughness, can
Y. Dong et al. / Surface and Coatings Technology 179 (2004) 223–228
227
Fig. 4. X-ray diffraction pattern of the MPSR composite coating.
restrain fine cracks expanding owing to the stress releasing. To a certain extent, the multiphase metal and ceramic coexistence can decrease the brittleness and increase the toughness of the MPSR composite coating. The opening porosity of the MPSR composite coating is shown in Table 2. The porosity of the MPSR composite coating is the lowest of the three because the reaction products of composite powders were fully melted by heat from plasma flame and the exothermic reaction of Fe2O3 –Al, while forming a high temperature and a high speed jet flow with little gas remaining in the MPSR coating. As a result, the density of the MPSR coating is the highest. For the SHS coating, reaction products were also fully melted and formed a pool before they solidified. The gas in reaction productions did not release because of the quick solidification. Therefore, the gas formed holes in the SHS coating.
the opposition. It indicates that the wear resistance of MPSR composite coating is better than that of pure Al2O3 coating and better than that of Ni–Cr–B–Si alloy coating under higher loads. The reason of the MPSR coating can endure heavy loads wear is that it has superior mechanical properties to the pure ceramic coating. Despite the fact that pure Al2O3 coating has higher Vickers hardness, it is brittle phase, in which micro-cracks easily come into being and expand under higher loads. In addition, heat produced by friction during testing is difficult to diffuse, raising the temperature of the coating quickly and accelerating the wear of the ceramic coating. However, metal and alloy phases in the MPSR coating are excellent conductors of heat, so the temperature of the MPSR coating remains low, even when the load rises to 490 N, thus the MPSR coating has excellent wear resistance under high loads.
3.4. Wear resistance of MPSR composite coating
4. Conclusions
Fig. 5 shows the volume loss of various wear-resistant coatings without lubrication. According to the results, volume losses of all coatings increase with increasing loads. The results show that the volume loss of the MPSR composite coating is lower than that of the pure Al2O3 coating under the same test condition. Compared with Ni–Cr–B–Si alloy coating, the volume loss of the MPSR composite coating is higher under lower loads; but when the load is higher than 392 N, the results are
1. According to Fe2O3q2Als2FeqAl2O3 q836 kJ, Al–Fe2O3 composite powders were produced, which were fit for plasma spraying. Fe2O3 and Al react adequately in plasma efflux forming the MPSR composite coating. 2. MPSR composite coatings were fabricated by plasma spraying Fe2O3 –Al composite powders. Hard Al2O3 ceramic and FeAl2O4 spinel are main phases forming
Table 1 Vickers hardness of different phase in the MPSR composite coating Phase
Ceramic Spinel Metal (Al2O3) (FeAl2O4) (Fe–Al alloy)
Vickers hardness (HV0.1 kgf) 1310
985
252
Table 2 Density and opening porosity of different coatings Coatings
Density (gymm3)
Opening porosity
MPSR coating SHS coating Al2O3 coating
4.3702 3.9518 3.7420
0.063 0.079 0.075
228
Y. Dong et al. / Surface and Coatings Technology 179 (2004) 223–228
Fig. 5. Curve of volume loss of different coatings.
the structure frame of the MPSR composite coating. Toughness metal Fe and FeAl alloy are the second phases. 3. The opening porosity of the MPSR composite coating is lower than that of the SHS coating. Wear resistance of the MPSR composite coating performs better than that of the plasma sprayed Al2O3 coating under different loads and better than that of the Ni–Cr–B– Si coating when load is up to 392 N. Acknowledgments The work was financially supported by the Natural Science Foundation of Hebei China (Grant No. 599031). References w1x J.B. Holt, Z.A. Munir, Combustion synthesis of titanium carbide: theory and experiment, J. Mater. Sci. 21 (1986) 251. w2x A.G. Merzhanov, B.G. Khaikin, Prog. Energy Combust. Sci. 14 (1) (1988) 1.
w3x A.G. Merzhanov, I.P. Borosinskaya, New class of combustion processes, Combust. Sci. Technol. 10 (1975) 195. w4x A.A. Zenin, A.G. Merzhanov, G.A. Nersisyan, Thermal Ware Structure in SHS Process (by the example of boride synthesis), Com. Explos. Shock Ware 17 (1) (1981) 63, (Engl Trans). w5x W.L. Frankhouse et al. Gasless Combustion synthesis of Refractory compounds, published by Noyes Publications in USA (1985). w6x X. Fan, Ishigakit, Fabrication of Composite SiC-MoSi2 Powders through Plasma Reaction Process Proceedings of the 15th International Thermal Spray Conference, Nice, France, 25–29 May 1998. w7x Foliot, Lacoura, Reactive Plasma Spray Forming for Ferromagnetic Materials Synthesis on Al Substrate Proceedings of the 15th International Thermal Spray Conference, Nice, France, 25–29 May 1998. w8x Wang Jiansheng, Toughness and adhesion of ceramic coatings, Trans. Mater. Heat Treatment 2 (2000) 24–35. w9x R.W. Smith, Plasma spraying process: proceedings of the 2nd Plasma-Technik Symposium, Vol. l, 1991, p. 17. w10x DIN51056: Bestinmung des offenens Porenranines Sept. 1959s. w11x YinSheng, Combustion Synthesis, 7, China, Metallurgical Industry Publishing Company, 1999, pp. 98–253.
Studies on composite coatings prepared by plasma spraying Fe2O3 –Al self-reaction composite powders Yanchun Dong*, Dianran Yan, Jining He, Xiangzhi Li, Wenran Feng, Hai Liu School of Material Science and Engineering, Hebei University of Technology, Tianjin 300130, PR China Received 13 January 2003; accepted in revised form 5 June 2003
Abstract Fe2O3 –Al composite powders were prepared using ferric oxide agent powders, aluminum powders and polyvinyl alcohol. Selfreaction composite coatings containing ceramic and metal multi-phases were fabricated by plasma spraying Fe2 O3 –Al composite powders. This technology successfully combines self-propagating high-temperature synthesis with plasma spraying. The morphology of the composite powders was examined by scanning electron microscope (SEM). The chemical composition, microstructure, Vickers hardness, density, porosity and wear resistance of the composite coating were studied. The wear resistance of the ceramic and metal multi-phase composite coating was significantly improved under heavy load. 䊚 2003 Elsevier B.V. All rights reserved. Keywords: Plasma spraying; Self-reaction; Ceramic coating; Composite coating
1. Introduction Self-propagating high-temperature synthesis or combustion synthesis (denoted as SHS) is a fairly simple technology with a high reaction temperature. It is difficult to control the reaction of SHS w1,2x because the process of SHS is very fast. The density of the material prepared by SHS is so low that the wear resistance and corrosion resistance of the coating is reduced w3–5x. It is noticeable that SHS cannot synthesise coatings on the surface of the axle or plane. For plasma spray, plasma efflux has the higher temperature (above 10 000 K) w6,7x and the higher velocity, which can almost melt all kinds of solid materials w8x. The density of plasma sprayed coatings is higher than that of coatings sprayed by other methods w9x. Polyvinyl alcohol was used to bind Al and Fe2O3 composite powders. Multi-phases self-reaction (denoted as MPSR) composite coating possessing excellent mechanical properties can be prepared by spraying these composite powders that can react in the plasma efflux. It is possible to prepare sintered composite coatings with the low power equipment. MPSR composite coating can also be made on *Corresponding author. Tel.: q86-22-2656-4581; fax: q86-222656-4774. E-mail address: [email protected] (Y. Dong).
surfaces of the axle and plane. The metal phase in the MPSR composite coating can improve the toughness of the MPSR composite coating. 2. Experiment 2.1. Experimental procedure The raw powders used in making composite powders were commercially available Fe2O3 and Al powders according to Fe2O3q2Als2FeqAl2 O3 q836 kJ. The sizes of Fe2O3 and Al particles are 30 mm and 50 mm, respectively. The polyvinyl alcohol was used as binder to bind Fe2O3 and Al powders together. The preparing process of composite powders was as follows: First, Fe2O3 and Al powders were thoroughly mixed for 24 h in a grinding machine. Secondly, the compounded powders were mixed again with polyvinyl alcohol solution. Thirdly, the compound was dried in an oven under 150 8C, shattered in a grinding machine and sifted through y80 and y120 mesh sifters. 2.2. Fabrication of the MPSR coating Samples of 30=25=10 mm were cut from a low carbon steel roller. Prior to spraying the MPSR composite coating, all the samples were sand-blasted to get
0257-8972/04/$ - see front matter 䊚 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0257-8972(03)00815-6
224
Y. Dong et al. / Surface and Coatings Technology 179 (2004) 223–228
Fig. 1. The SEM image of composite powders.
rough surfaces. Ni-10 wt.%Al self-melting alloy bond layer with a thickness of approximately 0.1 mm was sprayed onto surfaces of the samples to increase the adhesive strength of the MPSR composite coating and the steel substrate. The coating was sprayed by means of GDP-2 type plasma spraying device, whose power is 50 kW, made by JiuJiang Spraying Device Company China, the spraying gun was self-designed and made. The Fe2O3 –Al composite powders were ignited by the plasma flame and reacted. 2.3. Measurement of the MPSR composite coating properties The morphology of composite powders and MPSR composite coatings were observed by means of XL30y TMP scanning electron microscope (SEM). The X’PertMPD X-ray diffraction instrument was adopted to analyse the phases composition of MPSR composite coating. Measurement of the opening porosity of coatings was carried out by Archimede’s method, referring to the industry standard of commonwealth Germany ‘DIN51056’ w10x. Vickers hardness of the coatings was measured by using the digital Vickers hardness tester made in Shanghai Taiming Optical Instrument Co. Ltd., China. A load weight 100 g was applied to perform the indentation and maintained for 15 s. Sliding wear test was carried out on the MM-200 wear test machine made in Xuanhua Material Test Machine Co. Ltd., China, with a sliding speed of 0.4;0.8 mys. The wear resistance of the MPSR coating was denoted with the volume loss, compared with a Ni-15Cr-3.5B-4.0Si-10Fe (Ni–Cr–B– Si) alloy coating and a pure Al2O3 ceramic coating. The distance of friction was 18 km under 0;2000 N load.
3. Experimental results and discussion 3.1. Morphology of composite powders The morphology of self-made Fe2O3 –Al composite powders is shown in Fig. 1. It can be seen from Fig. 1 that the surfaces of all Al particles were partly or completely enwrapped by Fe2O3 particles. It was found through experiments that approximately 90% Al particles’ surfaces were completely enwrapped by the Fe2O3 particles. Most composite powders are fit for the reaction of Fe2O3q2Als2FeqAl2O3, according to the reaction equation, superfluous Al or Fe2O3 powders attributing to partly enwrapped result in intermediate reaction productions FeAl2O4, FeAl and Fe3Al appeared in MPSR composite coating. 3.2. Microstructural characterization of the MPSR composite coating Fig. 2 shows the SEM microstructure of the MPSR coating and Fig. 3 gives the energy-dispersive spectrum analysis of corresponding phases in Fig. 2. It is shown that four phases appear in the MPSR composite coating. The light phase (zone A) in Fig. 2 is metal Fe, whose spectrum is shown in Fig. 3a, the light grey phase (zone B) shown in Fig. 2 is alloy FeAl, whose spectrum is shown in Fig. 3b, the dark phase (zone C, E) is Al2O3 ceramic shown in Fig. 3c and e, the grey phase (zone D) is FeAl2O4 spinel. Fig. 4 shows the X-ray diffraction patterns of the MPSR composite coating. It is found that the MPSR coating consists of Al2O3, FeAl2O4, metal Fe, FeAl and Fe3Al, which indicates that Al and Fe2O3 in the composite powders have completely reacted. The FeAl2O4 phase came from the chemical equation Al2O3qFeOs
Y. Dong et al. / Surface and Coatings Technology 179 (2004) 223–228
225
Fig. 2. SEM image of the MPSR composite coating.
FeAl2O4, FeO coming from the Fe2O3 reduced w11x. FeAl and Fe3Al came from contiguous Fe and Al melted. It can be seen from Figs. 4 and 2 that Al2O3 ceramic and FeAl2O4 spinel phases form the structure frame of
the MPSR composite coating. Fe, FeAl and Fe3Al are the second phases. It is well known that the Al2O3 ceramic and FeAl2O4 spinel are hard and brittle phases, metal Fe possessed high toughness. As a result, the
Fig. 3. The energy-dispersive spectrums of the MPSR coating.
226
Y. Dong et al. / Surface and Coatings Technology 179 (2004) 223–228
Fig. 3 The energy spectrum of MPSR coatings.
coexistence of metal phases and ceramic phases can effectively improve the toughness of the coating. 3.3. Vickers hardness, porosity and density of the MPSR composite coating The Vickers hardness of different phases of the MPSR composite coating is listed in Table 1. It can be known
from Table 1 that the Vickers hardness of Al2O3 ceramic is 1310HV0.1. The Vickers hardness of FeAl2O4 spinel is lower than that of Al2O3. The Vickers hardness of the metal and alloy is the lowest among the phases, only 252HV0.1. Stress concentration and fine cracks easily form in the hard and brittle Al2O3 ceramic when the MPSR composite coating sustains impact and stress. Metal and alloy, which have excellent toughness, can
Y. Dong et al. / Surface and Coatings Technology 179 (2004) 223–228
227
Fig. 4. X-ray diffraction pattern of the MPSR composite coating.
restrain fine cracks expanding owing to the stress releasing. To a certain extent, the multiphase metal and ceramic coexistence can decrease the brittleness and increase the toughness of the MPSR composite coating. The opening porosity of the MPSR composite coating is shown in Table 2. The porosity of the MPSR composite coating is the lowest of the three because the reaction products of composite powders were fully melted by heat from plasma flame and the exothermic reaction of Fe2O3 –Al, while forming a high temperature and a high speed jet flow with little gas remaining in the MPSR coating. As a result, the density of the MPSR coating is the highest. For the SHS coating, reaction products were also fully melted and formed a pool before they solidified. The gas in reaction productions did not release because of the quick solidification. Therefore, the gas formed holes in the SHS coating.
the opposition. It indicates that the wear resistance of MPSR composite coating is better than that of pure Al2O3 coating and better than that of Ni–Cr–B–Si alloy coating under higher loads. The reason of the MPSR coating can endure heavy loads wear is that it has superior mechanical properties to the pure ceramic coating. Despite the fact that pure Al2O3 coating has higher Vickers hardness, it is brittle phase, in which micro-cracks easily come into being and expand under higher loads. In addition, heat produced by friction during testing is difficult to diffuse, raising the temperature of the coating quickly and accelerating the wear of the ceramic coating. However, metal and alloy phases in the MPSR coating are excellent conductors of heat, so the temperature of the MPSR coating remains low, even when the load rises to 490 N, thus the MPSR coating has excellent wear resistance under high loads.
3.4. Wear resistance of MPSR composite coating
4. Conclusions
Fig. 5 shows the volume loss of various wear-resistant coatings without lubrication. According to the results, volume losses of all coatings increase with increasing loads. The results show that the volume loss of the MPSR composite coating is lower than that of the pure Al2O3 coating under the same test condition. Compared with Ni–Cr–B–Si alloy coating, the volume loss of the MPSR composite coating is higher under lower loads; but when the load is higher than 392 N, the results are
1. According to Fe2O3q2Als2FeqAl2O3 q836 kJ, Al–Fe2O3 composite powders were produced, which were fit for plasma spraying. Fe2O3 and Al react adequately in plasma efflux forming the MPSR composite coating. 2. MPSR composite coatings were fabricated by plasma spraying Fe2O3 –Al composite powders. Hard Al2O3 ceramic and FeAl2O4 spinel are main phases forming
Table 1 Vickers hardness of different phase in the MPSR composite coating Phase
Ceramic Spinel Metal (Al2O3) (FeAl2O4) (Fe–Al alloy)
Vickers hardness (HV0.1 kgf) 1310
985
252
Table 2 Density and opening porosity of different coatings Coatings
Density (gymm3)
Opening porosity
MPSR coating SHS coating Al2O3 coating
4.3702 3.9518 3.7420
0.063 0.079 0.075
228
Y. Dong et al. / Surface and Coatings Technology 179 (2004) 223–228
Fig. 5. Curve of volume loss of different coatings.
the structure frame of the MPSR composite coating. Toughness metal Fe and FeAl alloy are the second phases. 3. The opening porosity of the MPSR composite coating is lower than that of the SHS coating. Wear resistance of the MPSR composite coating performs better than that of the plasma sprayed Al2O3 coating under different loads and better than that of the Ni–Cr–B– Si coating when load is up to 392 N. Acknowledgments The work was financially supported by the Natural Science Foundation of Hebei China (Grant No. 599031). References w1x J.B. Holt, Z.A. Munir, Combustion synthesis of titanium carbide: theory and experiment, J. Mater. Sci. 21 (1986) 251. w2x A.G. Merzhanov, B.G. Khaikin, Prog. Energy Combust. Sci. 14 (1) (1988) 1.
w3x A.G. Merzhanov, I.P. Borosinskaya, New class of combustion processes, Combust. Sci. Technol. 10 (1975) 195. w4x A.A. Zenin, A.G. Merzhanov, G.A. Nersisyan, Thermal Ware Structure in SHS Process (by the example of boride synthesis), Com. Explos. Shock Ware 17 (1) (1981) 63, (Engl Trans). w5x W.L. Frankhouse et al. Gasless Combustion synthesis of Refractory compounds, published by Noyes Publications in USA (1985). w6x X. Fan, Ishigakit, Fabrication of Composite SiC-MoSi2 Powders through Plasma Reaction Process Proceedings of the 15th International Thermal Spray Conference, Nice, France, 25–29 May 1998. w7x Foliot, Lacoura, Reactive Plasma Spray Forming for Ferromagnetic Materials Synthesis on Al Substrate Proceedings of the 15th International Thermal Spray Conference, Nice, France, 25–29 May 1998. w8x Wang Jiansheng, Toughness and adhesion of ceramic coatings, Trans. Mater. Heat Treatment 2 (2000) 24–35. w9x R.W. Smith, Plasma spraying process: proceedings of the 2nd Plasma-Technik Symposium, Vol. l, 1991, p. 17. w10x DIN51056: Bestinmung des offenens Porenranines Sept. 1959s. w11x YinSheng, Combustion Synthesis, 7, China, Metallurgical Industry Publishing Company, 1999, pp. 98–253.