摘要
C/C复合材料具有优异的力学性能,在航天航空、核能、化工、汽车、医疗等多个领域具有较高的应用潜力,但由于高温下会被迅速氧化,限制了其应用极限,在C/C复合材料表面制备抗氧化陶瓷涂层是提高其高温抗氧化性能的有效手段之一。本文依据不同抗氧化机理对当前C/C复合材料高温陶瓷防护涂层进行了归类讨论,并对C/C复合材料高温陶瓷抗氧化涂层的未来发展方向进行了适当展望。
C/C composite materials have several advantages,i.e.,low density,high thermal conductivity,low thermal expansion coefficient,and resistance to ablation,which can be used in various fields such as aerospace and nuclear chemical engineering.However,the susceptibility of C/C composite materials to oxidation in high-temperature environments is a primary concern for their further application.One effective solution is the fabrication of high-temperature oxidation-resistant ceramic coatings on the surface of C/C composite materials.The existing high-temperature oxidation-resistant ceramic coatings for C/C composites are gradually transited from single-layer to multi-layer.Typically,these composite coatings consist of three components,i.e.,a mitigating layer,an intermediate layer and a sealing layer.The mitigating layer serves to alleviate the thermal expansion coefficient mismatch between the substrate and the coating,while an oxygen-blocking layer characterized by a low oxygen diffusion rate prevents external oxygen from penetrating the substrate.The sealing layer with low porosity,high-temperature fluidity,and self-healing properties protects against environmental medium erosion.This review categorizes the existing high-temperature oxidation-resistant coatings of C/C composites based on different oxidation resistance mechanisms of ceramic coatings,i.e.,ceramic coatings based on self-healing glass phase protection mechanisms,ceramic coatings based on enhanced glass phase protection mechanisms,and antioxidant coatings based on composite glass phases.The ceramic coatings based on enhanced glass phase protection mechanisms are further divided into ion-enhanced glass phases,microporous-inclusion structure enhanced glass phases,and particle-enhanced glass phases.In the self-healing glass phase protection mechanism coatings,SiO_(2) and B_(2)O_(3) are the most common glass phases.However,single-layer SiO_(2) or B_(2)O_(3) coatings are restricted in their application at>1000℃due to the volatilization of the generated B_(2)O_(3) glass phase.It is thus necessary to incorporate both silicides and borides into the coating to facilitate the formation of a silicon-boron glass phase from their high-temperature oxidation products(i.e.,SiO_(2) and B_(2)O_(3)),thereby enhancing the oxidation resistance at>1000℃.In addition,SiOC glass phases can also improve oxidation resistance at>1000℃.In ion-enhanced glass phases,Ta and Hf ions exhibit significant reinforcement effects on the glass phase.Specifically,Ta ions due to its intense ionic complexation form a coral-like oxide framework with Hf ions,acting as a supporting scaffold in the Ta-Hf-Si-O glass phase.This enhances the viscosity and strength of the glass layer and the oxygen barrier capability of the coating.Hf cations diffuse into the SiO_(2) lattice,creating more stable chemical bonds that increase the thermal stability of SiO_(2) glass,allowing the glass phase to continue protecting the substrate from oxidation in a wider temperature range for an extended period.In microporous-inclusion structure enhanced glass phases,the microporous structure can inhibit crack propagation,while the inclusion structure can suppress the tendency for coating cracking,thereby also enhancing oxidation resistance.A research indicates that SiC-Si coatings with microporous structures can protect C/C composites from oxidation at 1500℃for 846 h,with a mass loss of only 0.16%.In particle-enhanced glass phases,the SiO_(2) glass phase generated upon oxidation of the coating becomes stable due to the incorporation of Zr compound particles as reinforcing phases,reducing the formation of cracks in the glass phase.This results in superior high-temperature oxidation resistance.For instance,La2O3-modified ZrB2-SiC coatings yield a Zr compound particle distribution in La-Si-O glass that forms a dense oxidation film,demonstrating the oxidation resistance at 1500℃for 550 h and at 1600℃for 107 h,while enduring 50 thermal cycles from 1500℃to room temperature with a mass gain of 0.35%.Researchers develop the coatings that can resist oxidation at 1700℃for 415 h based on the aforementioned antioxidant mechanism.In coatings based on composite glass phases,silicate and aluminate composite glass phases synergistically utilize the advantages of different glass phases.In addition to exhibiting self-healing functions,they also possess a superior oxidation resistance,remaining stable under high-temperature and oxidative conditions.Moreover,elements such as Zr,Y,and Al can capture oxygen molecules,forming a stable oxide layer that further protects the C/C substrate from oxidation damage.In addition,this review also represents the specific preparation processes and oxidation resistance effects for coatings based on oxide-generated glass phase protection mechanisms,enhanced glass phase protection mechanisms,and silicate glass phase coatings.Summary and Prospects This review offers a prospective outlook on the development of oxidation-resistant coatings for C/C composites.Firstly,novel reinforcing phases,such as one-dimensional and two-dimensional materials,can be doped to design and optimize the synthesis of ultra-high-temperature oxidation-resistant ceramic materials via efficient artificial intelligence approaches.This involves more complex combinations of the existing oxidation-resistant coatings or mechanisms to actively explore new systems of oxidation-resistant coatings for C/C composites capable of withstanding at>1700℃.Secondly,constructing a complete and reliable performance database for the existing C/C composite oxidation-resistant coatings can elucidate the related protective mechanisms,establish reasonable evaluation mechanisms,and explore key control methods,thereby providing design parameters and theoretical support for practical applications.Finally,a research should focus on the adaptability of oxidation-resistant coatings on C/C composite components of various sizes and configurations,optimizing preparation processes,revealing critical control factors,forming stable process control pathways,and developing relevant process standards.
作者
王麓焱
刘荣军
王衍飞
李端
缪花明
WANG Luyan;LIU Rongjun;WANG Yanfei;LI Duan;MIAO Huaming(School of Materials Science and Engineering,Nanchang Hangkong University,Nanchang 330063,China;Science andTechnology on Advanced Ceramic Fibers and Composites Laboratory,College of Aerospace Science and Engineering,NationalUniversity of Defense Technology,Changsha 410073,China)
出处
《硅酸盐学报》
北大核心
2025年第3期688-699,共12页
Journal of The Chinese Ceramic Society
基金
新型陶瓷纤维及其复合材料重点实验室基金(6142907220301)。
关键词
碳/碳复合材料
抗氧化
表面涂层
抗氧化机理
carbon/carbon composites
antioxidant
surface coating
antioxidation mechanism
