Preparation of Titanium Carbide by Carburisation of Titanium Dioxide

Abstract

Titanium carbide has attracted widespread attention due to its excellent properties. This study investigates the process of carbon thermally reducing TiO₂ to prepare TiC through a combination of thermodynamic analysis and experiments. The effects of temperature, TiO₂/C molar ratio, and time on the phase transformation and morphology evolution of the products are investigated. The synthesis of titanium carbide involves the main reduction path of TiO₂–Magnéli–Ti₃O₅–Ti₂O₃–TiC_xO_1−x. With the increase in reaction temperature and TiC content, the microstructure transitions from a smooth disc-like structure to a loose and porous layered structure, while the particle size decreases significantly. The carburisation rate of the reduced product is more affected by temperature, according to chemical analysis. The carburisation rate increased from 18.37% to 36.09% for 2 h–10 h of holding time at 1400 °C, and from 51.43% to 77.57% for 2 h–10 h of holding time at 1500 °C. The quantification of the carburisation rate provides a valuable reference for the preparation of titanium carbide by TiO₂.

1. Introduction

TiO₂, which is an important titanium-containing material, is used to produce sponge titanium and other high-value titanium-containing products, including titanium carbide. Titanium carbide is a typical transition metal carbide with a high melting point, high hardness (28.5–32 GPa), excellent elastic modulus, good conductivity, low density, and good corrosion resistance [1,2,3,4,5,6]. It is widely applied in the fields of metal ceramics, mechanical manufacturing, and electrode materials [7,8,9,10]. Apart from that, TiC serves as an adsorbent for adsorbing gases, such as NH₃, CH₄, CO, etc., for environmental remediation due to its large specific surface area and rich active sites [11]. The broad application prospects of titanium carbide have attracted a large number of scholars to explore various synthetic methods for titanium carbide.

To avoid intermediate products and synthesize high-quality titanium carbide, Dunmead et al. employed direct carbothermal reduction by metallic titanium powder and carbon [12]. It costs a lot to use titanium metal as a raw material. Titanium tetrachloride can react with calcium carbide or methane to produce TiC [13,14,15,16]. Titanium tetrachloride is highly corrosive, so the corrosion resistance of the reaction vessel is crucial. Compared to titanium powder and titanium tetrachloride, titanium dioxide as a raw material is more popular. TiC can be formed by the reaction of solid carbon and titanium dioxide with a high temperature (1700–2000 °C) and long reaction time (10–20 h) [17,18]. The diffusion of carbon is the controlling step in the reaction. Hence, increasing the temperature and time facilitates the formation of carbides [19]. In addition to solid carbon, hydrocarbon gases are alternative reducing agents. Professor Oleg Ostrovski has conducted research on the chemical reactions of Cr₂O₃, MnO, and CH₄. The results have shown that methane, as a carbonizing agent, can facilitate the formation of carbides at lower temperatures and shorter times compared to traditional carbon sources [20,21]. This discovery has opened up a new pathway for the carbothermic reduction of metal oxides. Zhang et al. showed that a mixture of methane and hydrogen can completely reduce TiO₂ to TiC_xO_y at 1350 °C for 8 h [22]. Methane is easily decomposed into carbon and hydrogen with increasing temperature, and carbon deposition causes the reaction to be hindered when the rate of methane decomposition is higher than the reaction [22,23,24]. The decomposition rate of methane cannot be determined, which makes it difficult to control the amount of carbon in the reduction process. In addition, both methane and hydrogen are highly flammable and explosive gases, so the equipment used for storage, transportation, and reaction processes must have high gas tightness requirements. The production cost of hydrogen is also high. Compared to gas reduction, solid carbon reduction is less hazardous and easier to control. Therefore, solid carbon is still dominant as a reducing agent in industrial production.

There have been many studies on the synthesis of carbides by the reduction of titanium oxides, but all of them are confined to the investigation of the reaction conditions and processes [22,23,25], and the degree of carbonisation of titanium oxides into titanium carbide has rarely been reported. Therefore, further research on the carbon thermal reduction of titanium oxides is necessary. The reaction process for the synthesis of titanium carbide was investigated by combining thermodynamic calculations and experiments. The evolutions in the phases and microstructure of the products are investigated by XRD and SEM. Finally, the ratio of carburisation is calculated based on the total titanium and titanium carbide content of the product obtained by chemical analysis, which directly reflects the synthesis of titanium carbide.

2. Materials and Methods

The pigment-grade TiO₂ and graphite powder are both analytical-grade reagents (99.9%, Aladdin Reagent Co., Ltd., Shanghai, China). Anhydrous ethanol is used as a dispersant (99.99%, Aladdin Reagent Co., Ltd., Shanghai, China). Argon gas is used as a protective gas (99.999%, Kunming Pengyida Gas Co., Ltd., Kunming, China). X-ray diffraction (XRD) of raw material is shown in Figure 1, which displays the diffraction peaks of rutile TiO₂. The scanning electron microscopy (SEM) of raw materials in Figure 1 shows that TiO₂ presents a smooth and dense disc-like structure. These disc-like particles are stacked and bonded to each other, meaning that TiO₂ is viscous and not easily dispersed.

Raw materials, TiO₂ and graphite, are mixed in a certain molar ratio. To prevent material stratification, anhydrous ethanol is added to the mixed powder as a dispersing agent, and the mixture is stirred in a magnetic stirrer to ensure uniform blending. Uniformly mixed material is then removed and dried in a drying oven at 120 °C for 6 h. Next, (3.0 ± 0.1) g of the mixture is removed and transferred to a pellet mould with a diameter of 15 mm. Subsequently, the mold is positioned onto a hydraulic press, applying a pressure of 2 MP to compact the powder into a sphere. Then, they are placed in a basket made of woven alloy wire as a substitute for a crucible. In addition, the basket is suspended in the temperature-controlled zone of the reaction furnace to maintain a constant temperature during the reduction process and adhere to the principle of controlling variables consistently. Argon gas does not participate in the reaction but serves as a protective gas. In addition to its role as a protective gas, argon can also be used to cool down the samples after the insulation time is completed. Argon is maintained at a constant flow rate of 300 sccm/min throughout the experiment.

The detection of the physical phase, micro-morphology, and elemental distribution of the products makes it possible to understand the course of the entire reaction process. The phase of the reduced product was determined using X-ray diffraction (XRD) with Cu Kα radiation. Scanning electron microscopy (SEM) was employed to observe the microscopic morphology of the samples. Microanalysis was performed using energy-dispersive spectroscopy (SEM/EDS) with an accelerating voltage of 10 kV. The product obtained from titanium oxide by carbothermal reduction is titanium oxycarbide rather than pure titanium carbide, which means that the degree of carbonisation of titanium oxide to titanium carbide needs to be obtained by calculation. Carburisation rate can directly reflect the synthesis of titanium carbide and be used as an important indicator for evaluating the degree of product carbonisation. A higher carburisation rate indicates higher amount of titanium carbide. Carburisation rate is the ratio of titanium carbonate (TiC) to total titanium (TTi) as in Equation (1) [26].

$$\eta =\frac{TiC}{TTi}\times 100\%$$

(1)

$TiC$ is the amount of titanium carbide in the product, wt%; $TTi$ is the amount of total titanium in the product, wt%; $\eta$ is the carburisation rate of the product percentage.

3. Results

3.1. Thermodynamic Calculation

Thermodynamic analysis is an important tool for predicting the reduction conditions and pathways. In this study, thermodynamic analysis was conducted by the equilibrium and reaction modules of the Factsage 8.1 software, with a database provided by Cao et al. [27]. The results of the calculation are displayed in Figure 2. From the graph, it can be observed that synthesizing titanium carbide from titanium dioxide occurs stepwise. As the temperature increases, titanium dioxide is progressively reduced to lower titanium oxides until Ti₃O₅ is formed, followed by the appearance of TiC. Interestingly, the occurrence of carbide reaction is not only dependent on temperature but also closely related to the carbon content. When the molar ratio of TiO₂/C is 1:2 at 1400 °C, the final product consists of both Ti₃O₅ and TiC. There is a reserve of Ti₃O₅ in the product, and insufficient carbon causes incomplete carburisation. Increasing the amount of carbon, the molar ratio of TiO₂/C = 1:3, and titanium carbide was the only product at 1400 °C, indicating that Ti₃O₅ is completely carburised to TiC. Further increasing the molar ratio to 1:4 leads to the coexistence of TiC and residual carbon in the product. A molar ratio of 1:3 results in the complete carburisation of the titanium oxide to TiC, whereas a molar ratio of 1:4 has residual carbon, resulting in a waste of carbon. The thermodynamic analysis suggests that the molar ratio of TiO₂/C is 1:3 and a temperature of 1400 °C are favorable for synthesizing TiC.

Merely utilizing the equilibrium module is not sufficient for predicting the reduction pathway. The sequence of the reactions can be deduced based on the Gibbs free energy of the reactions. It is highlighted that all reactions have the potential to occur within the designated temperature range in Figure 2d. It is also demonstrated that TiO₂ is initially reduced to Ti₃O₅. The temperatures for the carbonation of Ti₃O₅ and Ti₂O₃ to TiC are very similar, as seen from the Gibbs free energies. However, in comparison to the reduction reaction, the carburisation of Ti₃O₅ is more likely to occur. The reduction of Ti₃O₅ to Ti₂O₃ requires a temperature of 1460 °C, while direct carburisation only requires 1350 °C, which leads to a preference for carburisation over the reduction of Ti₂O₃. This clarifies why the calculation results of the equilibrium module do not show Ti₂O₃. Combining the above thermodynamic calculations, including the physical phase transition and the Gibbs-free energy of the reaction, it is easy to obtain the pathway for the synthesis of TiC by the reaction of TiO₂ and C as TiO₂–Magnéli–Ti₃O₅–TiC (TiC_xO_1−x).

3.2. Effect of Temperature

Thermodynamic analysis results indicate that carbon and temperature are important factors for the preparation of titanium carbide. The influence of temperature on the reduction process is investigated with a molar ratio of TiO₂/C of 1:3 and a holding time of 10 h. The X-ray diffraction (XRD) results displayed in Figure 3 illustrate the outcomes of various reduction temperatures. Carbon and TiO₂ are a solid–solid reaction, and contact between the reactants and reaching the required temperature are prerequisites for the reaction to occur. The dominant phases are Ti₂O₃ and carbon, while a little of TiO₂ is present at 1300 °C, implying that TiO₂ is not completely reduced. A reduction reaction can occur, but the rate is very slow, leading to incomplete reduction. No carbide is detected at this temperature, meaning the carburising reaction has not yet started, or the carburising reaction is weak and the amount of carbide produced is too low to be detected. Raising the temperature to 1400 °C, signs of carbide are observed, suggesting that Ti₂O₃ is carburized to form carbides, but the carburization rate is slow. Thermodynamic calculations predict that complete carburisation into TiC is achievable at 1400 °C, but there is a discrepancy with the experimental results, which is attributed to the impeded diffusion of gaseous products and the reduced contact area of titanium oxide with carbon as the reaction proceeds. The reduction of TiO₂ leads to pores hindering the contact between carbon and reactants and decreasing the reaction rate [28]. At 1500 °C, the predominant phase is TiC_xO_1−x, meaning that higher temperatures enhance the rate of carbide formation. Higher temperatures are an effective way to increase the rate of carburization. When the temperature increases from 1300 °C to 1500 °C, the diffraction peaks of titanium oxides decreases and the diffraction peaks of carbides are enhanced, indicating that there is a shift from a reduction-dominated reaction to a carbonation-dominated reaction in the TiO₂–C system. Additionally, the diffraction peak strength of carbon decreases sharply with a diffraction peak of carbide increases, signaling that a higher amount of carbon is required for carbide compared to reduction.

3.3. Carbon Content

The effects of carbon content were investigated at 1500 °C and 10 h of holding time. The evolution of phases is shown in Figure 4. When the molar ratio of TiO₂ to C is 1:1, the reduction products consist of Ti₂O₃, a little carbon, and carbides. The primary function of carbon is to reduce TiO₂ to low-valence titanium oxide. The desired TiC_xO_1−x phase appears at TiO₂/C = 1:1, indicating that the carbide reaction has started. Although the presence of carbides can be detected, the low intensity of the diffraction peaks shows that the amount of carbon is crucial for the formation of TiC_xO_1−x. Increasing the carbon content enhances the diffraction peaks of TiC_xO_1−x, while simultaneously decreasing the diffraction peaks of Ti₂O₃. This observation suggests that the reaction for carbide formation is intensified at the molar ratio of 1:2 TiO₂ to C. The characteristic peaks of TiC_xO_1−x dominate, leaving a few Ti₂O₃ phases at TiO₂/C = 1:3. Further increasing the molar ratio of TiO₂ to C does not result in any change apart from excess carbon, which leads to increased costs associated with subsequent carbon separation. When compared to other phases, the diffraction peaks of carbon exhibit a higher intensity at TiO₂/C = 1:4, a result that aligns with the findings of thermodynamic calculations. The appropriate amount of carbon is one of the key factors for synthesizing TiC_xO_1−x. In addition, carbon can be detected due to its high oxidation resistance and thermal stability [29]. Carbon does not readily oxidize or decompose at high temperatures and remains relatively stable, making it an important reducing and carbonizing agent.

3.4. Holding Time

Figure 5 displays the reduction products at various holding times with a molar ratio of 1:3 at 1500 °C. After 2 h, high-valent titanium oxides are rapidly reduced to low-valent titanium oxides and carburisation occurs. The product is composed of carbon, Ti₂O₃, and carbide. That is, when the temperature and the amount of carbon are appropriate, the carburisation reaction occurs rapidly. Diffraction peaks of TiC_xO_1−x became stronger and the diffraction peaks of Ti₂O₃ decreased after 4 h, indicating that more and more oxides were transformed into carbide. At a holding time of 6 h, TiC_xO_1−x emerged as the predominant phase, demonstrating that carbide increases with prolonged holding time. At 8 h, the diffraction peak intensity of titanium oxide and carbon decreased. Continuing the extension of holding time to 10 h, the phase composition of the products remained unchanged and the peak intensities of carbon and Ti₂O₃ decreased, while the peak intensity of TiC_xO_1−x increased. After 12 h of holding, there was no significant change, meaning that there was no sense in extending the holding time. At 2 h–6 h, carbon diffraction peaks decreased sharply, the number of diffraction peaks for Ti₂O₃ decreased, and the diffraction peaks of carbide increased gradually, indicating that there was sufficient carbon around the oxide and that the rate of the carburisation reaction was fast. However, at 8 h–12 h, the product diffraction peaks show little change and the rate of the carburisation reaction decreases, which is attributed to the lower amount of carbon and its non-uniform distribution. Reduced contact between the carbon and the oxide causes the reaction to be more difficult. The reduction process can be described as TiO₂–Magnéli–Ti₃O₅–Ti₂O₃–TiC_xO_1−x based on our experimental findings. However, these results differ from the reduction process predicted by thermodynamic calculations, which will be discussed in the following sections.

3.5. Carburisation Rate

The content of total titanium and titanium carbide in the product was obtained based on chemical analysis as shown in

Table 1. Content of titanium carbide and total titanium (1400 °C and 1500 °C), holding time is 2–10 h.

Temperature (°C)	Time (h)	TiC (wt%)	TTi (wt%)
1400	2	11.02	48
1400	4	15.57	51
1400	6	20.74	52
1400	8	23.62	53
1400	10	23.91	53
1500	2	36	56
1500	4	50	61
1500	6	56	63
1500	8	62	65
1500	10	64	66

. The amount of both titanium carbide and total titanium increased with increasing temperature and holding time, which demonstrated enhanced carburisation. Combined with Table 1 and Equation (1), the carburisation rate is calculated as shown in Figure 6, which increases with temperature and holding time. At 1400 °C, the carburisation reaction has occurred, and the rate of carburisation is relatively low. After a 2 h insulation period, the carburisation rate is measured to be 18.4%. Despite the potential benefits of prolonging the insulation time for carbide formation, even after a 10 h insulation period, the carburisation rate only reaches 36.1%. This suggests that there are still numerous titanium oxides remaining that have not undergone carburisation. At 1500 °C, the carburisation rate is 51.43% after 2 h. This finding strongly suggests that temperature plays a crucial role in influencing the carburisation reaction, and higher temperatures result in more vigorous carburisation reactions. By further extending the incubation time to 10 h, an impressive carburisation rate of 77.6% is achieved. In other words, at 1500 °C, a prolonged holding time is favourable to improve the degree of carburisation of titanium oxides. Interestingly, the carburisation rate does not uniformly increase as the incubation time is extended. The carburisation rate increases rapidly during the insulation period of 2 to 8 h, but afterwards, the rate of increase slows down. The intensification of the carbon gasification reaction leads to an increase in the partial pressure of CO with temperature rising. The gas fills the pores hindering direct contact between carbon and titanium oxide, which slows down the carburisation reaction. Additionally, the diffusion of carbon also serves as a factor influencing the carburisation reaction. The diffusion of unreacted carbon to regions in direct contact with titanium oxide is crucial for the continuation of the carburisation process. As the carburisation reaction progresses, the required time for carbon to diffuse to the target locations increases, resulting in a slower increase in the carburisation rate.

4. Discussion

4.1. Reduction Route

TiC_xO_1−x was prepared at a molar ratio of TiO₂/C = 1:3, at 1500 °C and 10 h. However, there are discrepancies between the thermodynamic calculations and experimental results regarding the path for synthesizing carbide. The presence of TiO₂, Magnéli, Ti₃O₅, and TiC, based on thermodynamic calculations, suggests that Ti₃O₅ is a precursor of carbide. Nevertheless, Ti₃O₅ was not detected in the experimental results, with the main phases being TiO₂, Ti₂O₃, and TiC_xO_1−x. Therefore, it can be inferred that the precursor for carbide is Ti₂O₃. The reason for the absence of Magnéli and Ti₃O₅ is that the rate of reduction from TiO₂ to Ti₃O₅ is very fast, and it is fully reduced under these experimental conditions. To explain the discrepancy between theoretical and experimental results, some clues can be drawn from the reaction equations. From the Reaction Equations (2)–(4), Ti₃O₅ directly carburizes into TiC, requiring eight moles of carbon. However, the pathway through Ti₃O₅–Ti₂O₃–TiC only requires 5.5 moles of carbon. Although the amount of carbon is sufficient to generate titanium carbide, during the reduction process, a portion of the carbon that comes into contact with the titanium oxide is consumed. As a result, the carbon content around the titanium oxide is reduced, causing Ti₃O₅ to be preferentially reduced rather than directly carburized. Koc and Folmer proposed that there are two pathways for the carbon thermal reduction of titanium oxide. When there is an excess of carbon and CO, Ti₃O₅ directly carburizes into carbide. However, if there is a deficiency of carbon and CO, it first undergoes a reduction to Ti₂O₃ and then carburizes into carbide [17]. In addition, the crystal structure is also one of the important factors influencing carburisation reduction. TiO₂ has a tetragonal crystal structure, Ti₃O₅ has a monoclinic crystal structure, Ti₂O₃ has a hexagonal crystal structure, and TiC has a cubic crystal structure. The reaction is related to the crystal structure of the material, according to Welham [25]. When oxygen in the reactants is removed, the product undergoes minor rearrangement, resulting in an increase in symmetry. This increase in symmetry facilitates the subsequent formation of the cubic phase. The reduction of Ti₃O₅ to TiC may be limited by crystallographic constraints. It is more advantageous in terms of kinetics to conduct the carburization process using the intermediate phase Ti₂O₃, which possesses symmetry. The process of synthesising carbide in this work is shown in Figure 7. Firstly, there is a reduction stage, where TiO₂ is reduced until Ti₂O₃. Then, there is a carburisation stage. Ti₂O₃ undergoes a carburisation reaction to produce carbide. Based on the above analysis, it is suggested that the reduction pathway for carbon thermal reduction of titanium oxide in this experiment is TiO₂–Magnéli–Ti₃O₅–Ti₂O₃–TiC_xO_1−x.

Ti₃O₅ + 0.5C = 1.5Ti₂O₃ + CO

(2)

Ti₃O₅ + 8C = 3TiC + 5CO

(3)

Ti₂O₃ + 5C = 2TiC + 3CO

(4)

4.2. Micro-Morphology

To facilitate the observation of changes in the morphology of the products, the reduced material was ground into a powdered form. Figure 8a,b show the micrographs of the raw material, while the TiO₂ surface is smooth and dense, presenting a disc-shaped structure. At 1300 °C, the surface of the samples starts to become rough, while the microstructure still retains the disc-shaped structure of the raw material. Upon further magnification, as shown in Figure 8d, the surface of the product exhibits a number of gas pores, which are caused by the release of CO during reduction. At this temperature, the main process occurring is the reduction of titanium oxides. The high-valence titanium oxides lose some oxygen and transform into low-valence titanium oxides. The reduction reaction cannot alter the original microstructure of the reactants; it only results in the generation of a rough and porous surface through the release of gas. When continuing to rise the temperature to 1400 °C, the samples completely deviate from the disc-shaped dense structure and exhibit a loose surface state. Titanium oxide undergoes carbide formation, which completely changes the original microstructure of the material at 1400 °C. As shown in Figure 8f, the surface of the product becomes porous and exhibits a layered structure. However, at this temperature, the carburisation rate is not high and there still exists a significant portion of densely structured titanium oxide. After grinding, the particle size of the product changes minimally. At 1500 °C, Figure 8g indicates that not only does the surface of the product become porous, but the particle size also decreases dramatically, which is attributable to the intensified carburisation reaction. The product, TiC_xO_1−x, exhibits a porous structure, and the particle size decreases after grinding. In other words, at this point, carbides become the main phase. By further increasing the magnification, it can be observed that the sample exhibits a layered structure, indicating that carbides grow layer by layer [30]. Figure 9 presents the Energy Dispersive X-ray Spectroscopy (EDS) results for different temperatures. EDS results show the elemental composition, and the product consists of three elements: Ti, C, and O. The differences in temperature result in variations in the elemental proportions. At 1300 °C, a small amount of carbon is distributed at the edges of the particles, while the denser regions of the product lack carbon distribution. The distribution of carbon elements reflects the locations of the carbides, showing that only a small amount of titanium oxide undergoes carbide formation. Furthermore, the atomic proportion of oxygen, which is 50.9%, further confirms that the primary constituent in the product is titanium oxide. At a temperature of 1400 °C, the particles exhibit a layered structure on their surface. The distribution of carbon elements throughout the entire particle indicates that the carburisation reaction is enhanced as the temperature increases. Simultaneously, there is a decrease in the proportion of oxygen atoms, due to a gradual transformation of oxides into carbides. At 1500 °C, three elements are evenly distributed. Firstly, the oxygen in the titanium oxide is removed by the carbon in the form of gas. After the reduction reaction is mostly completed, carbon slowly diffuses towards the edges of the titanium oxide, depleting oxygen and infiltrating into oxygen vacancies to form titanium oxycarbide. With the progress of the carburisation reaction, the oxygen in titanium oxycarbide gradually decreases, and the corresponding amount of titanium carbide increases. The rate of carbide formation is primarily determined by the diffusion of carbon. In addition, higher temperatures promote carbon diffusion, thereby facilitating the formation of carbides.

5. Conclusions

This study combines thermodynamics and experiments to investigate the process of preparing titanium carbide through the thermal reduction of TiO₂ and carbon (C). The following conclusions have been obtained:

• The temperature, carbon content, and time are three important factors in the preparation of TiC_xO_1−x. Increasing the temperature provides heat for the reaction and promotes the diffusion of carbon into the surrounding titanium oxide, triggering the reaction. The appropriate carbon content is crucial for the preparation of carbides. A lower amount of carbon content yields only a small quantity of carbides, whereas an excessive carbon content results in a surplus of carbon and subsequently increased costs for separation. In addition, TiC_xO_1−x was prepared with a molar ratio of TiO₂/C = 1:3 at a temperature of 1500 °C for a duration of 10 h.
• The intermediate phases Magnéli and Ti₃O₅ were not detected; they were attributed to the fast reduction rate of TiO₂ to Ti₂O₃, which does not mean that Magnéli and Ti₃O₅ were not produced during the reaction, and the titanium oxides were reduced stepwise. All of TiO₂ was reduced to Ti₂O₃, suggesting that the reduction ended and was followed by the carburisation of Ti₂O₃. In addition, the synthesis of titanium carbide involves the main reduction path: TiO₂–Magnéli–Ti₃O₅–Ti₂O₃–TiC_xO_1−x.
• As the temperature rises from 1300 °C to 1500 °C, the amount of carbide increases. The microscopic morphology of the material gradually deviates from the original smooth and dense cake-like structure, which becomes rough and porous. After the abundant formation of carbides, the material displays a porous layered structure of carbides, which is completely separate from the original structure.
• Temperature has a greater effect on the carburisation ratio compared to time. At a temperature of 1400 °C, with a holding time ranging from 2 h to 10 h, the carburisation ratio increases from 18.37% to 36.09%. At 1500 °C, the carburisation ratio increases from 51.43% to 77.57%. Overall, increasing the temperature and time favours the generation of titanium carbide.