Carbon-carbon Composite Materials Research Articles

Impact of process parameter on the behavior of pyrocarbon deposition in chemical vapour infiltration (CVI) process

Carbon-carbon composite manufactured by deposition of pyrocarbon (PyC) through chemical vapor infiltration (CVI) has the key issue of being process parametric sensitive which necessitates the detailed study of the effect of process parameters on the rate of PyC deposition. Conventional method of studying the parametric effect by changing one variable at a time keeping the other variables constant has a limitation of more number of experiments and missing the interaction effect among the variables. Here, the effect of process parameters including temperature, pressure, methane gas flow rate, and nitrogen gas flow rate on the mass gain and PyC deposition was studied by Taguchi method, a statistical optimization method, which has the advantage of very few experiments performed at specific pairs of process parameters only. The experiments were performed at three levels of the process parameters. Carbon-Carbon composite material is processed through the CVI process where PyC was deposited on porous carbon fiber preforms at various process conditions as per the Taguchi method. The impact of gas residence time, Reynolds number, Prandtl number, and Peclet number were also investigated. It was observed that the CVI process parameters significantly affect the rate of PyC deposition. Optimized CVI process parameters are essential for achieving a high rate of PyC deposition to reduce the processing time. The findings have revealed that a higher PyC deposition rate arises under high temperatures, pressure, methane gas flow rate, and optimal nitrogen gas flow rate. The effect of the critical interaction of the CVI process parameters on the rate of PyC deposition was also obtained. Based on the experimental studies, process guidelines are proposed for the densification of carbon fibers preform to realize C/C composite products.

An overview of carbon-carbon composite materials and their applications

Carbon-carbon composites are advanced materials known for their high strength, high-temperature stability, and superior thermal conductivity. Mechanical properties such as tensile strength, flexural strength, and compressive strength are examined, as well as thermal properties like the coefficient of thermal expansion and thermal conductivity, to understand the characteristics of the composite. Carbon-carbon composites are ideal for the aerospace industry’s need for lightweight and high-performance materials. Tribological and surface properties are relevant to this discussion, given the use case of carbon-carbon composites in extreme conditions, the effect of exposing the composite to different fluids and the change in friction and wear properties. Coatings can protect the composite from environmental factors such as UV radiation, oxidation, and erosion. Self-healing composites that can repair themselves can increase the lifespan of structures while reducing maintenance costs. These have been used in aerospace applications such as airplane braking systems, rocket nozzles, and re-entry vehicle heat shields. Furthermore, researchers have recently addressed the problem of finishing and drilling without delamination and loss of properties, and this study looks into unconventional methods that can be adopted for the same. This study aims to provide an overview of the current state of carbon-carbon composite materials and their applications.

RESEARCH OF HEAT RESISTANCE OF CARBON-CARBON COMPOSITE MATERIALS WITH PROTECTIVE COATINGS OBTAINED USING FUNCTIONALLY ACTIVE CHARGES

This study focuses on the development of protective coatings for carbon-carbon composite materials (CCСM) used in high-temperature processes in aerospace engineering. CСCM have limitations due to their susceptibility to oxidation, erosion, and burnout in gas streams. Our research is aimed at creating protective coatings using functionally active charges (FAC) obtained under non-stationary temperature conditions and improving the performance of composites. The aim of our study is to identify the optimal compositions of powders for chromium-alloyed protective coatings using functionally active charges to increase the heat resistance of the working surface. We analyzed various methods of obtaining protective coatings, including chemical-thermal and liquid-phase saturation methods, to find out their peculiarities in interaction with the CCСM matrix and changes in their mechanical properties. In addition to the traditional methods, we have investigated the method of saturating the surface with a solid phase in an active gas environment using FAС, which are obtained under non-stationary temperature conditions. This method provides high quality coatings, reduces processing time and makes it possible to work at high temperatures depending on the composition of the spray coatings. Much attention was paid to the problem associated with chemical interaction and formation of carbide phases, which are important for ensuring the stability of coatings under high temperature conditions. Experimental studies include a factorial experiment to determine the compositions of powder mixtures that provide high heat resistance. Various independent variables, such as the content of chromium, silicon, titanium, and aluminum, were considered, taking into account their influence on the physical and mechanical properties of coatings. Particular attention was paid to the optimization of the parameters of thermal autoinitiation of the functionally active charge under process conditions. Regression equations are presented to evaluate the dependence of the wear resistance of coatings on the autoinitiation parameters and the content of alloying elements. The analysis of the study results includes the construction of three-dimensional graphical dependencies for optimizing the composition of powdered CBA in the Cr-Al-Ti and Cr-Al-Si systems. In practice, chromium-aluminum-siliconized coatings obtained under isothermal conditions, when tested for heat resistance, have a more porous surface through which oxygen penetrates to the surface of the HCCM. Compared to the coatings obtained using FAS, the heat resistance is 1.5-1.7 times higher, which can be explained by the higher concentration of chromium, aluminum, silicon, and titanium, which contribute to the formation of protective oxide membraness. The low-porosity surface of the coatings obtained using functionally active layers prevents oxygen from entering the material, contributing to the formation of oxide protective membranes such as SiO2, TiO2, Cr2O3, Al2O3.

Fluid-solid-ablation coupled calculation of hypersonic vehicle based on rbf grid deformation method

The ablative phenomenon of the thermal protection system happens when the hypersonic vehicle suffers serious challenges of aerothermal due to high Mach number. To determine whether the thermal protection system is destroyed, the fluid-solid-ablation loosely coupled method for Carbon-Carbon composite materials is proposed to calculate the deformation of ablation and acquire the deformed shape. Navier-Stokes equation, heat conduction equation, and linear ablation model are applied to calculate the fluid field, the solid field, and the ablation receding amount. As one of the most widely applicable dynamic mesh methods, the Radial Basis Functions (RBF) dynamic method is used to get the deformed solid mesh. The ablation of a missile is computed and analyzed. It could be found that the surface temperature of the head increases during flight and the ablation of the surface results in the change of the vehicle’s shape. The ablative layer thickness of the thermal protection system should be greater than the max ablative deformation, reaching 4.4 mm of the missile. The proposed fluid-solid coupling method could effectively predict the ablation deformation of the vehicle and guide the design of hypersonic vehicle thermal protection systems.

Advantages and disadvantages of carbon-carbon composite materials in the field of shells and structural materials

Since contemporary information-retrieval systems rely heavily on the content of titles and abstracts to identify relevant articles in literature searches, great care should be taken in constructing both. Carbon-carbon composites are advanced materials with excellent performance and a wide range of application prospects. In the aerospace sector, carbon-carbon composites are widely used in housings and structural materials, where their excellent mechanical, thermal and heat resistance make them ideal choices. This article applies two methods of literature review and case study and reviews the application of carbon-carbon composites in the aerospace field, focuses on their application in shells and structural materials, and analyzes and discusses their advantages and challenges in depth. Carbon-carbon composite materials have broad application prospects in the aerospace field, and their advantages lie in lightweight design, thermal resistance, mechanical properties, and oxidation resistance.

The influence of thermal expansion of carbon-carbon composite materials on the stability of their tribological parameters

The influence of thermal expansion of disk specimens made of carbon-carbon composite materials on the stability of their tribological characteristics in a friction pair with a ceramic ring counterbody is studied theoretically and experimentally. The temperature characteristics of composites with two different structures — fibrous and fabric — are studied. The experimental dependences of the load change on time during frictional heating are compared with the calculation model obtained by methods of contact interaction mechanics. A relation is established between changes in interface stiffness and the dependence of the coefficient of thermal expansion on temperature for the materials under study. Uneven wear of the fabric composite is revealed at the initial stage with destruction of fabric layers and tearing out of structural components. Keywords:carbon-carbon composite material, contact interaction, friction, temperature, frictional heating, coefficient of thermal expansion, wear ivan.yu.tsukanov@gmail.com, lyubicheva@mail.ru, bukovskiy.pavel@gmail.com

USING OF CARBON-CARBON COMPOSITE MATERIALS FOR CREATION OF THERMAL-RESISTIVE CONVERTER OF THERMAL RADIATION

The article presents the results of work aimed at research of electric-physical properties of carbon-carbon composite material (CCCM) under conditions of heat exchange by radiation in vacuum and creation of a thermalresistive heat radiation converter for measuring temperatures up to 2500 °C.

Carbon-carbon composite material in friction units when lubricated with hydraulic fluid

The paper deals with the issues related to the friction of carbon-carbon composite against steel in the medium of hydraulic fluid. Variation of friction coefficient from load, speed and temperature is analyzed. Comparison of antifriction properties of Hardcarb TP material with fluoroplastic modified by radiation treatment is performed. It is established that under the conditions of the experiments, the carbon composite has a higher friction coefficient than the fluoroplastic, but acceptable (f = 0.12) for use in friction units. Hardcarb TP material is promising for application in sliding friction friction units in lubrication with AMg-10 working fluid under conditions of increased requirements for the reliability and service life of hydraulic pumps.

Friction carbon-carbon composite materials for rolling stock braking systems

Friction carbon-carbon composite materials for rolling stock braking systems

The influence of thermocyclic effects on the tribological properties of a carbon-carbon composite under braking conditions

The article considers the issues of the influence of repeated thermal shock on the frictional properties of a carbon-carbon composite material. For thermal loading, the heat-pulse method was applied, in which the energy of rotating masses is absorbed by a friction couple from samples of the material being studied. The change in the friction coefficient during braking is analyzed. Based on the results of repeated braking, conclusions are drawn about the resistance of the material to thermal cyclic behaviours. Particular attention is paid to the maximum temperature that occurs on friction surfaces and the temperature change during thermal loading. The dependence of the average friction coefficient in each test on the number of loading cycles was obtained. Based on the study, the number of thermal loads at which the frictional properties of the material are stable was established.

Improving the packing and mechanical properties of graphite blocks by controlling filler particle-size distribution

Mechanical qualities play a critical role in increasing the industrial applications of carbon-carbon composite materials as their porosity determines the strength of the material. In this study, carbon blocks with improved packing properties were produced by controlling various particle size distributions of coke particles. Particle-size diversity and geometric packing structure favorably affected the packing properties of the powder. Coke samples with tap densities up to 1.258 g/mL were prepared by controlling the size distribution of the coke particles. The porosity of the carbon block was calculated using three density definitions. The closed pores were reduced by up to 13.68% through the packing density of the particles, and the open pores were controlled by the coke/pitch mixing conditions regardless of the tap density. The carbon block showed a total porosity of 21.61% and a maximum compressive strength of 131 MPa by controlling the tap density of the coke. The proposed technique will be useful in various industries that require appropriate tap density control and will improve the compressive strength of composite materials.

CURRENT LEADS FOR RESISTIVE CCCM HEATERS

The article justifies the necessity of taking into account the transient electrical resistance of the welding contact between the titanium current lead and the resistive element of the heater made of carbon-carbon composite material (CCCM) during its manufacturing.
 Carbon-carbon composite material possesses a unique set of technical characteristics that make it suitable as a structural material for manufacturing resistive heaters operating in the temperature range from 400°C to 2500°C in a vacuum or protective atmosphere. The use of CCCM heaters in the thermal chambers of electrothermal engines to convert electrical energy into thermal energy allows them to be employed for temperature measurement inside the engine's thermal chamber. The utilization of an integrated temperature assessment of the CCCM heater, which relies on the resistance change of the heater with increasing temperature and essentially involves measuring the electrical current passing through the heater, requires ensuring accurate values of both the electrical resistance of the heater itself and the electrical resistance at the point of contact with the current lead.
 The design of the heater has a particular feature, which is the need to supply electrical current to two lamellas of the resistive element of the CCCM heater, located on one side of the heater. For welding the joints between the titanium wire and the resistive element of the heater, TIG welding with a surface arc in an argon environment was applied, with argon being supplied between the welding point and the non-consumable tungsten electrode.
 Laboratory tests revealed that detachable connections of the titanium wire to the resistive element of the CCCM heater and separable connections (such as bolts, screws, and wedges) cannot meet the requirements for contact resistance stability for various reasons. Among non-detachable connections, only welded joints demonstrated stable electrical contact resistance characteristics.
 The electrical resistance of the heater with current leads should be 3.8±0.2 Ohms. The tolerance value for resistance is determined by several factors, including the physical properties of CCCM, the technology of mechanical processing, the method of applying protective coatings, the resistance of the welding joint, and others.
 During mechanical tests of the welding joint between the titanium wire and the heater, it was observed that the wire detachment from the heater occurs with residues of CCCM and a transitional layer of titanium carbide, which forms during welding and can contribute to additional electrical resistance of the heater. Thermal deformation of the CCCM heater in the welding zone does not occur.
 The results of the conducted research demonstrate that the installation of titanium current leads by welding increases the resistance value of the resistive element of the CCCM heater due to the chemical reaction between the titanium alloy and the resistive element, leading to the formation of an additional layer of titanium carbide. Therefore, the electrical resistance of the resistive element of the CCCM heater during its manufacturing, before welding two titanium wires for current leads, should be reduced, taking into account the transitional electrical resistance of the two welding contacts.

APPLICATION OF CARBON-CARBON COMPOSITE MATERIALS FOR THE MANUFACTURE OF HIGH-TEMPERATURE HEATERS OF HEAT EXCHANGERS WITH AUTOMATIC TEMPERATURE CONTROL


 The article justifies the use of high-temperature heaters made of carbon-carbon composite material (CCCM) for the thermal unit of a silicon single crystal growth chamber. The conducted analysis confirms that the electrical properties of composite materials, specifically their specific resistance, allow for the creation of heating elements for high-temperature vacuum furnaces or furnaces operating in inert atmospheres at temperatures up to 2200°C.
 The use of heaters made from carbon-carbon composite material eliminates the main drawback of graphite heaters - uncontrolled energy dissipation during resistive heating due to the presence of transient electrical resistance at the junctions of graphite plates, and ensures a more uniform temperature field throughout the chamber volume. The capabilities in terms of the maximum permissible temperature of such a CCCM heater exceed the working temperature by more than two times, which also positively affects the service life.
 The modes of thermal processes occurring during crystal growth are determined by the technological process depending on the composition of the raw material and require high uniformity of heating in the working zone, high precision, and stability of the heater's temperature control. For precise temperature regulation, it is proposed to additionally measure the integral temperature in the chamber indirectly, which is based on measuring the electrical current passing through the heater, which is in thermodynamic equilibrium with the object. Thus, the heater is considered as a system susceptible to various thermal influences that determine the heat transfer process and the temperature change within the chamber and in the zone of the thermal unit's bricks.
 An improved structural diagram of a step-type extremal control system is proposed for automatic temperature control of a high-temperature heater using modern power electronics, sensors, microprocessors. To ensure speed and accuracy in temperature control, the pulse-phase control method implemented with modern specialized thermoregulator with PID-regulation was applied.
 Experimental tests conducted on the «Redmet-30» installation under factory conditions confirm the energy efficiency of using high-temperature heaters made of CCCM.

IMPROVING THE THERMAL STABILITY OF CARBON-CARBON COMPOSITE MATERIALS USING SELF-PROPAGATINGHIGH-TEMPERATURE SYNTHESIS

Abstract.This research focuses on the development of effective protective coatings for carbon-carbon composite materials (CCСM), which are important components in high-temperature processes in aerospace engineering. The application of CCСM is limited by their sensitivity to oxidation, erosion and burnout in gas streams. In light of these limitations, our work is aimed at creating protective coatings using the method of self-propagating high-temperature synthesis, which provide increased performance and extend the service life of composites. The main task of the research is to identify the optimal compositions of powders for chromium-doped protective coatings through the SHS process. Various methods of obtaining protective coatings were analyzed, including chemical-thermal methods and methods of saturation from the liquid phase, revealing the peculiarities of the interaction of coatings with the CCСM matrix and changes in their mechanical characteristics. In addition to the classical methods of obtaining coatings, the method of surface saturation from the solid phase in an active gas environment as part of the SHS process was investigated. This method provides high-quality coating surfaces, reduction of processing time and the possibility of reaching high temperatures, depending on the composition of the SHS mixture. An important element of the research is the analysis of modern publications and research in the field of protective coatings. Special attention is paid to the problems associated with chemical interaction with the matrix of CCСM and uneven formation of carbide phases along the cross-section of the material. Experimental studies include a factorial experiment to identify the compositions of powder mixtures that provide high wear resistance. Various independent variables, such as chromium, silicon, titanium and aluminum content, are considered for their effect on the physical and mechanical properties of the coatings. The study focuses on the optimization of the parameters of thermal autoinitiation of SHS mixtures under process conditions. The regression equation for evaluating the dependences of the wear resistance of coatings on auto-initiation parameters and the content of alloying elements is given. The analysis of the research results includes the construction of three-dimensional graphic dependencies to optimize the wear resistance of coatings in the Cr-Al-Ti and Cr-Al-Si systems. Chromoalumosilicization of the coating showed better wear resistance, exceeding the wear resistance of untreated samples by 2.6-3.2 times, which allows the use of this technology for parts of aerospace equipment. It is interesting that the porous surface of coatings obtained by the SHS method prevents the penetration of oxygen into the material, contributing to the formation of oxide protective membranes, such as SiO2, TiO2, Cr2O3, Al2O3.

Results of a clinical trial of humeral neck osteosynthesis with carbon – carbon composite material

The metals utilized in the production of various implants in traumatology possess all the required mechanical properties. However, these materials are susceptible to oxidation. Carbon-carbon composites, on the other hand, exhibit X-ray transparency and are easily machinable. Thanks to their intricate yet essential physical, mechanical, and chemical properties, they find effective application in osteosynthesis and endoprosthesis procedures for bone structures. The aim of this study is to comparative view of the treatment outcomes for patients with fractures of the proximal part of the humerus by carbon-carbon composite material plates and titanium plates. Materials and methods. In this study, a carbon-carbon composite material plate was conducted osteosynthesis of the proximal part of the shoulder. In the comparison group, a titanium plate was employed. The study group comprised 20 patients, while the comparison group included 15 patients. The analysis of the results was carried out utilizing the Constant–Murley scale and the Quick DASH questionnaire. Results. A comparative study of treatment outcomes between the main and comparison groups revealed a more significant positive treatment effect in the group that underwent osteosynthesis of the humeral neck by a carbon-carbon composite material plate. This effect was observed at the 3-month, 6-month, and 12-month evaluation points. It was characterized by reduced shoulder pain, alleviated dysfunction manifestations, enhanced daily activities, and improved overall quality of life among patients in this group. Conclusions. The analysis of long-term treatment outcomes for proximal humerus fractures, utilizing both carbon-carbon composite material plates and titanium plates, by the Constant–Murley scale and the Quick DASH questionnaire, demonstrated statistically confirmed improvements in shoulder joint function for both treatment methods.

Robust Micro-Sized and Defect-Rich Carbon-Carbon Composites as Advanced Anodes for Potassium-Ion Batteries.

Pitch-derived carbon (PC) anode features the merits of low-cost, rich edge-defect sites, and tunable crystallization degree for potassium ion batteries (PIBs). However, gaining the PC anode with both rich edge-defect sites and robust structure remains challenging. Herein, micro-sized and robust PC/expanded-graphite (EG) composites (EGC) with rich edge-defect sites are massively synthesized via melting impregnation and confined pyrolysis. The PC is in situ encapsulated in micro-sized EG skeleton with robust chemical bonds between PC and EG after thermal treatment, endowing the structural stability as micro-sized carbon-carbon composites. The confinement effect originating from EG skeleton could suppress the crystallization degree of the PC and contribute rich edge-defect sites in EGC composites. Additionally, the EG skeleton inside EGC could form continuous electronic conduction nets and establish low-tortuosity carbonaceous electrodes, facilitating rapid electron/ion migration. While applied in PIBs, the EGC anode delivers a reversible capacity that up to 338.5mAhg-1 at 0.1Ag-1 , superior rate performance of 127.5mAhg-1 at 5.0Ag-1 , and long-term stability with 204.8mAhg-1 retain after 700 cycles at 1.0Ag-1 . This novel strategy highlights an interesting category of heterogeneous carbon-carbon composite materials to keep pace with the demand for the future PIBs industry.

Масштабные эффекты в резьбовых деталях из пространственно-армированных углерод-углеродных композиционных материалов

The paper presents results of studying the impact of the strength and stiffness scaling effects in modern spatially reinforced carbon-carbon composite materials on bearing capacity of the products made from them. These materials are widely used in equipment operating under extreme conditions of simultaneous loading with force and temperature factors. When designing such products, it becomes necessary to understand the influence degree of the frame damaged during machining on observed properties of the material used, including dimensions, at which it is required to consider reduction in strength and stiffness, as well as the value, which could reduce the considered properties.

Experimental studies of truck transport brake pads materials friction properties

The work presents the results of experimental systematic studies of "wheel-brake pad" friction pairs wear resistance and the effect of the wear-resistant coating on the wear, in particular, from metal-ceramic friction materials (ФМК-8), carbon composite materials (ВВКМ) in comparison with carbon steel of grade 45. It was established that the instantaneous values of brake pads friction coefficients during the tests on inertial stand are random in nature and require the use of mathematical statistics methods for their analysis. Change nature in pads and wheels friction force instantaneous values is determined by pressing forces. It is shown that the mathematical expectation of the friction coefficients values is within the normalized permissible interval. The probability of friction coefficients instantaneous values matching into the normalized interval at a pressing force of 10kN is 0,6-0,8 for speeds up to 60 km/h, for the rest is more than 0,8 at pressing force of 20kN, the specified probability exceeds 0,85 for the entire range of speeds. With a pressing force of 20kN, the probability of values exceeding the normalized interval does not exceed 0,15, with a pressing force of 10kN, the friction coefficients exceeded the maximum normative values more than 0,35 for speeds up to 40 km/h. It has been established that the most wear-resistant pads are coated with metal-ceramic material (ФМК-8) and carbon-carbon composite materials (ВВКМ). It is shown that the described technique based on the mathematical statistic application allows to perform more in-depth analysis of freight wheeled road trains brake pads frictional properties.

Possibilities of Using Low-Density C–C Composites for Thermal Protection of Small Unmanned Aerial Vehicles

Abstract The study demonstrates the possibilities of using, as well as the features associated with the use of, unmanned aerial vehicles (UAVs) for military and peaceful purposes. Information is provided on the need to use components that would contribute towards ensuring thermal protection against modern laser weapons. The requirements for such materials are given, according to the field of application of the UAV. An analysis of the available materials that can be used to create thermal protection of UAVs against laser weapons is provided. The thermophysical characteristics of various materials are presented. The work presents technological features of production and properties of low-density carbon–carbon composite materials (CCCM). It is proposed to consider the prospects of using CCCM materials for not only the UAV structural components but also other purposes.

THE USE OF CCCM FOR THE CREATION OF THE HIGH-TEMPERATURE DETECTORS OF THE WATER WAPOR

A technique for assessing the presence of water vapor in a mixture using high-temperature detectors made of carbon-carbon composite material (CCCM) is proposed. The change in the electrical resistance of CCCM in a mixture containing water vapor at a temperature of 1000 °C is presented. The efficiency of such detectors has been tested and experimentally confirmed.