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The macrokinetic characteristics of combustion of the quaternary Ti-Zr-B-C mixture as well as the mechanism and stages of phase formation for the synthesis products were investigated. The mechanical and thermophysical properties of the hot-pressed boride/carbide ceramics with eutectic composition (Ti,Zr)B 2 -43%at.(Zr,Ti)C were measured. Preliminary mechanical alloying (MA) of the (Zr + Ti) mixture was shown to yield Ti/Zr granules having a laminar structure and consisting of alternating layers of titanium, zirconium, and (Zr,Ti) ss solid solution. The method used to prepare reaction mixtures and the initial temperature T 0 increased within the range of 20–370 °C have virtually no effect on combustion temperature, which is 2260–2400 °C, while higher T 0 increases the combustion rate by a factor of 1.5–2. The use of MA Ti/Zr granules reduces the combustion rate as well as the specific heat release amount and the heat release rate. Time-resolved X-ray diffraction data showed that binary carbides (Zr 1-x Ti x)C and diborides (Ti 1-y Zr y)B 2 of variable stoichiometry are formed in the combustion wave of the Ti-Zr-B-C reaction mixtures within less than 0.25 s. The carbide and diboride phases are formed simultaneously; the use of MA Ti/Zr granules in the reaction mixtures reduces the content of solid solutions of variable stoichiometry among the reaction products. The ceramics fabricated using a combination of combustion synthesis and hot pressing have a dense and homogeneous structure that consist of bonded grains of the diboride (Ti 0.80 Zr 0.20)B 2 and carbide (Zr 0.83 Ti 0.17)C phases having the following properties: density, 5.3 g/cm3; hardness, 22.9 GPa; fracture toughness, 4.7 MPa m0.5; heat capacity, 0.52 J/(g·K); thermal diffusivity, 11.67 mm2/s; and thermal conductivity, 33.28 W/(m·K). [ABSTRACT FROM AUTHOR]

This paper focuses on the effect of mechanical activation (MA) of Fe–Al–B reaction mixtures on the macrokinetic characteristics of combustion and structure formation of the synthesis products calculated for the formation of the Fe 2 AlB 2 MAB phase. Phase diagrams of the ternary system in question are constructed at different temperatures using the AFLOW and Materials Project databases. The effect of initial temperature (T 0) on the key SHS parameters is demonstrated. The combustion temperature varies within the 1110–1220 °C range; autoignition of the MA mixture occurs at T 0 > 200 °C. The impact of MA on heat release and structural phase transformations in reaction mixtures is investigated. The optimal modes of MA and SHS that allow one to synthesize a product containing up to 99% of the Fe 2 AlB 2 phase are identified. The ceramics produced in the layerwise SHS combustion mode inherit the structure of the mechanocomposite and consist of composite agglomerate particles sized up to 30 μm with grain size up to 2 μm. The stages of structural phase transformations taking place in the combustion wave during the production of the MAB phase are studied by the quenching of the combustion front and dynamic X-ray diffraction. Fe 2 AlB 2 is formed from the metallic boron-containing melt, without intermediate formation. [ABSTRACT FROM AUTHOR]

This article presents a study on the manufacturing of three-phase TaSi 2 –TaC–SiC ceramics through self-propagating high-temperature synthesis (SHS) and their subsequent chemical conversion to TaC–SiC carbide composites during transient liquid-phase hot pressing (HP). The effect of carbon black doping, ranging from 0% to 7%, on the degree of chemical conversion, structure, mechanical, and thermophysical properties of the ceramics was investigated. Our results showed that the proportionate increase of carbide content and decrease of TaSi 2 content in hot-pressed samples was achieved through carbon black doping. The increase of TaSi 2 content during hot pressing led to an increase in porosity from 4.3% to 23.8%, while the density decreased from 6.3 to 4.6 g/cm3. Superior mechanical properties were obtained when SHS-powder was doped with 1.5% carbon black (HV = 15.2 GPa, K IC = 4.8 MPa × m1/2, and σ bend = 331 MPa). The structure of the ceramics was characterized by a TaSi 2 –SiC matrix and highly dispersed TaC grains predominantly residing inside TaSi 2 , with the TaC–TaSi 2 and TaSi 2 –SiC interface being incoherent, as demonstrated through TEM studies. Complete conversion of TaSi 2 to TaC and SiC was achieved through 7% carbon black doping, resulting in the hot-pressed sample consisting solely of carbide grains. Two-stage hot pressing was employed to enhance the relative density of the two-phase TaC–SiC sample, resulting in ceramics characterized by HV up to 22.3 GPa, K IC up to 6.1 MPa × m1/2, σ bend up to 256 MPa, and λ up to 36 W/(m × K). [ABSTRACT FROM AUTHOR]

The kinetics and stages of phase formation in the combustion wave of the MoAlB mixture are studied. The phase diagrams in the Mo-Al-B system were built using the AFLOW and Materials Project databases. The time-resolved X-ray diffraction analysis demonstrate that the MoAlB phase crystallizes from the melt without formation of any intermediate compounds. The structure of the synthesized ceramics was MoAlB lamellar grains 0.4 µm thick and ~2–10 µm long. Compact samples characterized by homogeneous structure and low residual porosity were obtained by hot pressing of SHS powders. The ceramic MoAlB has a layered structure, which is consistent with the morphology of the synthesis products. Mechanical and thermophysical properties are measured for samples obtained under optimal HP conditions at 1300 °C. The calculated value of the oxidation rate for MoAlB at 1200 °C for 30 h was 2.21∙10−5 mg/(cm2∙s). Oxide layer ~14 µm thick consists of elongated polygonal Al 2 O 3 grains. [ABSTRACT FROM AUTHOR]

This paper focuses on the kinetics and the mechanism of oxidation (at 1650°C) of the ceramics based on the (Hf 0.8 Ta 0.2)B 2 , β-SiC and LaF 3 (0 and 3.5 wt%) phases fabricated by a combination of self-propagating high-temperature synthesis (SHS) and hot pressing (HP). The physicomechanical and thermophysical properties of the ceramics were determined. The effect of doping with lanthanum on the kinetics and mechanism of oxidation as well as the structural and morphological features of the resulting oxide layers after efficiency of their protective action was analyzed. The evolutionary changes in the structure were studied: the formation of a three-layered heterogeneous oxide film, modification of borosilicate glass with Hf4+, Ta5+ and La3+ cations, formation of Hf4+-doped La 1/3 TaO 3 globules followed by their growth via the Ostwald ripening mechanism, generation and oxidation of the secondary TaB 2 phase, significant reduction of the content of the HfSiO 4 phase, etc. Doping the ceramics with lanthanum was shown to exhibit a negative effect on high-temperature oxidation resistance, and the main reasons for that were analyzed. [ABSTRACT FROM AUTHOR]

• Dense heterophase HfB 2 –SiC ceramics produced by hot pressing of SHS powders. • The best heat resistance was observed for the ceramics with 8 % SiC under gas-dynamic conditions. • A dense protective layer consisting of HfO 2 /HfSiO 4 grains is formed on the surface during oxidation. • Ceramics exhibits: heat capacity - 0.38 J/(g × K), thermal diffusivity - 40.9 mm2/s, and thermal conductivity - 89.7 W/(m × K). The kinetics and the mechanism of oxidation of ceramics based on HfB 2 and SiC, manufactured by elemental self-propagating high-temperature synthesis followed by hot pressing were investigated. The synthesis product contained HfC (x) and HfO 2 as impurity phases. Depending on the ratio between the main components, the samples were characterized by high structural and chemical homogeneity, porosity of 3–6 vol%, hardness up to 29 GPa, bending strength of 500–600 MPa, fracture toughness of 5.6–8.9 MPa × m1/2, and thermal conductivity of 86.0–89.7 W/(m × K). The oxidation was performed under static conditions at 1650 °C and upon exposure to a high-enthalpy gas flow. A dense layer consisting of HfO 2 /HfSiO 4 grains formed on the surface of the ceramics during both oxidation conditions; the space between the grains was filled with amorphous SiO 2 –B 2 O 3. The best heat resistance was observed for the ceramics with 16 wt% SiC for static conditions and 8 wt% SiC for gas-dynamic conditions. [ABSTRACT FROM AUTHOR]

Composites MoSi 2 –ZrB 2 –SiC and MoSi 2 –HfB 2 –SiC were investigated in this study as the prospective materials for high-temperature industrial heaters. The composites with relative density 97–98% were produced by combustion synthesis followed by hot pressing. The macrokinetic features of combustion, as well as phase and structure formation mechanisms in the combustion waves, were analyzed and their influence on the structure, mechanical properties, and performance of heaters were ascertained. The mechanical and electrical properties of the heating elements produced in this work are considerably higher as compared to conventional MoSi 2 counterparts. Among the investigated compositions, the MoSi 2 –HfB 2 –SiC demonstrated the highest resistance to high-temperature oxidation. Both compositions featured the formation of a stable continuous oxide layer consisting of crystalline α-quartz (high-temperature modification of SiO 2) reinforced by ZrO 2 , ZrSiO 4 , HfO 2 , and HfSiO 4 precipitates. [ABSTRACT FROM AUTHOR]

This study focuses on the kinetics and mechanisms of oxidation at 1200 and 1650 °C for the ceramics based on (Hf,Ta)B 2 -SiC. The effect of primary phase content on structural and morphological features of the nascent oxide layers and the efficiency of their protective action is analyzed. The evolutionary changes in the structure at the micro and nanolevels are studied. Doping the ceramics with Ta is found to negatively or positively affect their oxidation resistance, and substantiation for this effect is provided. Ceramics containing 8% SiC are shown by their maximum high-temperature oxidation resistance at 1200 °C and 25% SiC at 1650 °C. [Display omitted] • (Hf 0.8 Ta 0.2)B 2 -SiC ceramics were obtained by combination of SHS and HP technologies. • XRD, SEM, TEM have been used to explain the mechanisms of (Hf,Ta)B 2 -SiC oxidation. • The Ta 1.5 O 4.55 and Hf 6 Ta 2 O 17 precipitates are perfect single crystals. • Secondary TaB 2 , TaC, (Hf,Ta)C phases are formed between oxide film and substrate. • Substitution of Hf by Ta in HfO 2 lattice makes to decrease in anion conductivity. [ABSTRACT FROM AUTHOR]

In this work, the influence of modifications of SHS-process on the microstructure and performance characteristics of composite ceramics MoSi 2 -HfB 2 -MoB with two-level structure was studied. Partial texturing of MoSi 2 grains in samples obtained by force SHS pressing technology was revealed. The effect of preliminary mechanical activation on the macrokinetic parameters of combustion and on the microstructure of the synthesized ceramics was studied. A significant grinding of the synthesized ceramics grain and an increasing of physical-mechanical properties are achieved by increasing the velocity and lowering the combustion temperature of the activated mixtures. The sample obtained by hot pressing of SHS powder from MA reaction mixture showed the most optimal combination of hardness (19.5 GPa), porosity (0.4%) and oxidation resistance (1.82∙10-6 mg/(cm2∙s)). [ABSTRACT FROM AUTHOR]

Abstract This study focuses on the investigation of the macrokinetic features of SHS (combustion synthesis) of elemental mixtures Mo–Hf–Si–B, in particular the mechanisms of structure and phase formation in the combustion front as well as the structure and properties of consolidated ceramics. Two routes for the fabrication of the composite SHS powder in system MoSi 2 –HfB 2 –MoB were used: (1) synthesis using Mo–Si–B and Hf–B mixtures followed by mixing of the combustion products and (2) synthesis using the four-component Mo–Hf–Si–B mixture. Dense ceramic samples with a homogeneous structure and low residual porosity (0.8–3.6%) were prepared by hot pressing of SHS powders. Although the particles size distribution and phase composition of SHS powders are similar for both synthesis routes, the structure and properties of both the composite SHS powders and hot-pressed ceramics differ considerably. Synthesis using the four-component Mo–Hf–Si–B mixture allows one to produce hierarchically ordered nanocomposite material with improved mechanical properties: hardness up to 17.6 GPa and fracture toughness up to 7.16 MPa m1/2. [ABSTRACT FROM AUTHOR]

The aim of this work was to study the kinetics and oxidation mechanism of MoSi 2 -MoB SHS-ceramics in the temperature range of 600–1200 °C. Due to the low rate of change in the mass of samples during the initial stage of oxidation, the kinetic curves at 600 °C suggest that the oxidation process occurs according to a parabolic rate law. At this temperature, MoO 2 and MoO 3 are formed in samples with the greatest MoB content due to its oxidation, and their intensive evaporation only begins after 700 °C. A thin film consisting of a mixture of Mo, Si and B oxides forms on the sample surface as a result of oxidation with a minimum MoB content. The presence of B 2 O 3 in the oxide film leads to the formation of a borosilicate barrier layer, which prevents oxygen diffusion to the sample surface and MoO 3 evaporation. At temperatures of 900 and 1200 °C, the oxidation process proceeds according to a logarithmic law. At these temperatures, an oxide film based on SiO 2 is formed on the surface layer, which in the case of the maximum MoB content sample, is a mixture of B 2 O 3 -SiO 2 oxides in an amorphous state. At lower MoB concentrations, the formed SiO 2 film has a crystalline structure and contains boron. In addition, during oxidation of the materials at the maximal temperature, a Mo 5 Si 3 silicide layer is formed at the interface between the oxide layer of B 2 O 3 -SiO 2 or B-SiO 2 and the sample material due to the oxidation of MoSi 2 , whose thickness and continuity increase with increases of the temperature and duration of oxidation. [ABSTRACT FROM AUTHOR]

Time-resolved X-ray diffraction was used to study the dynamics of phase formation in magnesium diboride produced by self-propagating high-temperature synthesis in the thermal explosion mode. The MgB 2 phase was demonstrated to emerge without the formation of intermediate compounds. The effect of the mixture heating rate on the formation mechanism of the MgB 2 phase was established. The presence of oxygen impurities has a significant impact on the kinetics and formation mechanism of MgB 2 . If the heating rate exceeds 150 °/min, the oxide coating is not formed around the magnesium particles, which results in the solid-phase reaction of Mg+2B=MgB 2 through a reaction diffusion mechanism. Moreover, the self-ignition temperature of the mixture is lower than the melting point for magnesium. Mechanical activation of the mixture leads to variations in the kinetics of MgB 2 formation, significantly increases the period of simultaneous existence of Mg and MgB 2 , and reduces the temperature at which the reaction occurs. [ABSTRACT FROM AUTHOR]

The results of a study focused on combustion synthesis of the biocompatible ceramic material TiC–Ti 3 PO x –CaO is reported. The effect of tricalcium phosphate (TCP) additives on the combustion process of the (100% – X )(Ti+0.5C)+ X % Ca 3 (PO 4 ) 2 mixture, and the phase and structure formation of synthesis products, was studied. Parallel chemical reactions between Ti and C and between Ti and Ca 3 (PO 4 ) 2 occur in the combustion wave. It was shown that the resulting melt is based on titanium, and TCP forms the reactionary surface by capillary spreading onto the carbon black surface. The SHS product consists of an interconnected skeleton of nonstoichiometric titanium carbide grains with the titanium phosphate (Ti 3 PO x ) phase distributed uniformly along the grain boundaries, with inclusions of calcium oxide (CaO). The presence of the CaTiO 3 phase is indicative of the interaction between calcium oxide and unreacted titanium in the post-reaction zone. Dense ceramic materials consisting of round-shaped grains of nonstoichiometric titanium carbide TiC 0.55 –TiC 0.6 , titanium phosphate (Ti 3 PO x ) and calcium oxide (CaO) were produced using the forced SHS- pressing technology. Increasing the TCP concentration reduces the size and hardness, but increases the residual porosity of structural components. [ABSTRACT FROM AUTHOR]

Kinetics of the SHS process, stages of chemical transformations and structure formation of ceramic materials in the Cr–Al–Si–B multicomponent system were investigated. The effect of reaction mixtures composition and initial temperature on the combustion rate U c and combustion temperature T c , which reduce with increasing Al content, was studied. An increase in the initial temperature of the SHS process causes a linear increase of U c and T c in the range of T 0 =290–750 K. This is evidence to the fact that each composition is characterized by the similar combustion mechanism, when the stages of chemical reactions of product formation remain unchanged. However, an increase in T 0 above 750 K, probably, may lead to exponential character of U c growth. Furthermore, an increase in Al content increases the proportion of the Al–Si eutectic melt. The dissolution of Cr particles in this melt becomes the rate-limiting stage of the combustion process, thus reducing the effective activation energy approximately from ~290 to ~110 kJ/mol. The stages of chemical transformations in the combustion wave were studied; the mechanism of structure formation was proposed. Firstly, the Al–Si eutectic mixture undergoes contact melting followed by formation of the reactionary surface as the melt spreads over the Cr and B particles surface. The melt is saturated with these elements followed by crystallization of CrB and Cr(Si,Al) 2 grains. In the Cr- and B-rich areas and low melt concentration, the formation of CrB may occur by solid-phase interaction supported via gas-transport reaction. Dynamic X-ray diffraction confirmed the sequential formation of chromium monoboride CrB and after chromium silicide Cr 5 Si 3 or chromium alumosilicide Cr(Si,Al) 2 . Force SHS–pressing was used to fabricate ceramic targets for magnetron sputtering of multicomponent coatings. [ABSTRACT FROM AUTHOR]

• Dense heterophase single-level (SLS) and two-level (TLS) structured MoSi 2 –HfB 2 –MoB ceramics produced by SHS. • Steady-state oxidation at temperatures up to 1650 °С and plasma torch testing at 2000 °С. • Formation of multi-layered and nano-strengthened oxide films. • SLS ceramics perform better under steady-state oxidation, TLS ceramics – under plasma torch testing. Influence of the composition and structure of the heterophase ceramics in system MoSi 2 –HfB 2 –MoB on the thermal conductivity, kinetics and mechanisms of oxidation at 1200 °C and 1650 °C, including the plasma torch testing at 2000 °C, was investigated. Dense ceramics with heterogeneous single-level structure (SLS) and two-level structure (TLS) were obtained by the hot pressing of powders produced by self-propagating high-temperature synthesis (SHS) in combustion mode. TLS ceramics have a lower thermal conductivity as compared to the SLS ceramics with similar elemental composition. Addition of hafnium diboride leads to the increase of mass change during the oxidation due to the formation of HfO 2 and HfSiO 4 , which are denser than SiO 2. In the case of the SLS ceramics, at 1200 °C a two-layered oxide film is formed. The upper layer is comprised of amorphous Hf-doped oxide layer, and the lower layer is crystalline crystoballite α-SiO 2. TEM investigation of samples oxidized at 1650 °C revealed the formation of HfSiO 4 precipitates in the α-SiO 2 matrix. In the case of the TLS ceramics, regardless of oxidation temperature two-layered oxide film consists of upper SiO 2 and lower HfSiO 4. TLS ceramics demonstrated the highest oxidation resistance under the plasma torch and kept its structural integrity during 180 s at 2000 °C. [ABSTRACT FROM AUTHOR]

The study focuses on investigation of the combustion kinetics and mechanisms, as well as the phase- and structure formation processes, during elemental synthesis of ceramics based on zirconium diboride and silicide doped with aluminum. The effect of the degree of dilution with an inert component and initial temperature T 0 on the combustion kinetics of the Zr–Si–Al–B mixture is studied. An increase in T 0 in the range of 298–700 K causes a directly proportional rise in the combustion temperature T c and rate U c , which demonstrates that staging of the reactions of formation of zirconium boride and silicide remains invariant. The effective activation energy E eff of the combustion process is 225 kJ/mol, suggesting that the liquid-phase processes have a decisive effect on the reaction kinetics. The interaction of zirconium with boron and silicon runs through the Zr–Si–Al–B melt that is formed in the combustion zone. Staging of chemical transformations during phase and structure formation of SHS products is studied. The primary ZrB 2 grains crystallize from the melt in the combustion zone; the ZrSi silicide phase is formed with a delay of no longer than 0.5 s. Compact ceramics with composition ZrB 2 –ZrSi–ZrSi 2 –ZrSiAl 2 synthesized by forced SHS- pressing showing a great potential for high-temperature applications both as a construction material and as a precursor for ion-plasma deposition of coatings. [ABSTRACT FROM AUTHOR]

In this study, the effect of mechanical treatment on the structure and phase composition of Ti+10% Ca 3 (PO 4 ) 2 powder mixtures was investigated. Ceramic Ti–Ti 3 P–CaO electrode materials with a high component homogeneity and a residual porosity of 5–7% were obtained in a process involving cold pressing and vacuum sintering. The erosive power of the sintered ceramic-metal Ti–Ti 3 P–CaO electrode during the electrospark treatment of titanium substrates was examined, and a comparison with the SHS TiC 0.5 –Ti 3 PO x –CaO electrodes was performed. Both the Ti–Ti 3 P–CaO and TiC 0.5 –Ti 3 PO x –CaO coatings exhibited high denseness with a width of approximately 20 μm, a hardness of 3.6 GPa, a roughness of 3.3–4.6 μm and a uniform distribution of bioactive calcium and phosphorus elements. [ABSTRACT FROM AUTHOR]

Abstract: The goal of this work is to investigate the combustion mechanisms of reactions in the Mo–Si–B system and to obtain ceramic materials using the SHS method. It is concluded that the following processes are defined by the SHS for Si-rich Mo–Si–B compositions: silicon melting, its spreading over the surfaces of the solid Mo and B particles, followed by B dissolution in the melt, and formation of intermediate Mo3Si-phase film. The subsequent diffusion of silicon into molybdenum results in the formation of MoSi2 grains and molybdenum boride phase forms due to the diffusion of molybdenum into B-rich melt. The formation of MoB phase for B-rich compositions may occur via gas-phase mass transfer of MoO3 gaseous species to boron particles. The stages of chemical interaction in the combustion wave are also investigated. The obtained results indicate the possibility of both parallel and consecutive reactions to form molybdenum silicide and molybdenum boride phases. Thus the progression of combustion process may occur through the merging reaction fronts regime and splitting reaction fronts regime. Molybdenum silicide formation leads the combustion wave propagation during the splitting regime, while the molybdenum boride phase appears later. Finally, targets for magnetron sputtering of promising multi-phase Mo–Si–B coatings are synthesised by forced SHS compaction method. [Copyright &y& Elsevier]

• Combination of SHS and HP use to obtain ceramics in the ZrSi 2 -MoSi 2 -ZrB 2 system. • Kinetics of oxidation at 1400 °C described using a power function with index n > 2. • Mostly the ZrSi 2 phase were oxidized. • Two-layer film formed during oxidation consist of silicate glass and ZrSiO 4 sublayer. • ZrSiO 4 with scheelite-type structure encapsulate the ZrB 2 and MoSi 2. The results of a study of the kinetics and mechanism of heterogeneous and compact ceramics oxidation in the ZrSi 2 -MoSi 2 -ZrB 2 system at air temperature of 1400 °C are presented. The ceramics were obtained by the hot-pressing of composite powders that were manufactured by self-propagating high-temperature synthesis following the magnesiothermal recovery approach. Oxidation kinetics are described using a power function with index n > 2 , confirming the significant influence on the evolution process in the structure of the formed oxidation coating. The oxidation mechanism includes the formation of a two-layer structure consisting of a continuous silicate film, of which the outer part contains magnesium and a sublayer based on the ZrSiO 4 phase, with the scheelite structure encapsulating the ZrB 2 and MoSi 2 grains. The influence of the ZrSi 2 , MoSi 2 and ZrB 2 phases on the structural-morphological peculiarities of the appearing oxide films and the effectiveness of its protective action are revealed. [ABSTRACT FROM AUTHOR]

Abstract The kinetics and mechanism of high-temperature oxidation of dense heterophase ZrSi 2 -MoSi 2 -ZrB 2 ceramics at a temperature of 1650 °C are studied. The ceramics were fabricated by hot pressing of composite powders prepared by self-propagating high-temperature synthesis with magnesiothermic reduction. The oxidation kinetic curve is described by the power-law function, which indicates that the evolutionary changes in the structure of the formed oxide films significantly affect the course of the oxidation process. The oxidation mechanism involves formation of a multi-layered structure of heterogeneous oxide film, partial dissociation of the ZrSiO 4 phase, and formation of secondary MoB and Mo 5 Si 3 compounds. The influence of the ZrSi 2 , MoSi 2 and ZrB 2 phases on the structural and morphological features of the formed oxide films and the efficiency of their protective action are shown. Silicon is reduced and zirconium is simultaneously oxidized to ZrO 2 in the ZrSi 2 -ZrSiO 4 system at temperatures above 1620 °C in the absence of oxygen or in low-oxygen environment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Coatings on C f /C-SiC were obtained by melting of ZrSi 2 -MoSi 2 -ZrB 2 SHS-powder layers. • The oxidation kinetics at 1650 °C in static air obeys the logarithmic law. • Heterogeneous borosilicate glass, ZrO 2 and SiO 2 layers are formed during oxidation. • The glass phase was doped with Zr and the secondary Mo/MoO 2 , Mo 3 Si, Mo 5 Si 3 phases were formed. • The ZrSi 2 end-to-end oxidation determines the exhaustion of the coatings protective effect. In this work, we investigate the oxidation resistance of the coatings manufactured by reactive impregnation of C f /C-SiC composites with a melt derived from layers of ZrSi 2 -MoSi 2 -ZrB 2 powder composition synthesized by SHS and alternating layers of SHS powders and elemental Si. Oxidation resistance tests were conducted in static conditions at 1650 °C in air and under an air plasma torch at 2200 °C. The performance of the coatings in these conditions is defined by the emergence and evolution of the heterogeneous oxide films based on zirconia-modified borosilicate glass. The protective oxide layers effectively inhibit the oxygen influx and further oxidation of the substrate. The increase of temperature above 1750−1800 °C resulted in evaporation of the glass phase from the surface and formation of porous thermally insulating ZrO 2 -based layer with Mo/MoO 2 , Mo 3 Si, and Mo 5 Si 3 inclusions. The gradient of temperature across the coatings' thickness allows for a partial retainment of the glassy phase in the coatings' lower layers due to the decrease of partial pressures of boron and silicon suboxides, resulting in an additional degree of protection against oxygen diffusion. The specimens were characterized in terms of the temperature and time boundaries of their performance, mass loss kinetics, catalytic activity, and spectral emissivity of the coatings. The limiting factors of the coatings' performance are outlined. [ABSTRACT FROM AUTHOR]